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Print Quality Troubleshooting Guide
This guide is a great place to start if you are trying to improve the quality of your 3D printed parts. We have compiled an extensive list of the most common 3D printing issues along with the software settings that you can use to solve them. Best of all, the guide uses a large collection of real-world images to make each issue easy to identify when examining your own 3D printed parts. So let’s get started!
Use the thumbnails below to identify the picture that most closely represents the quality issue that you are seeing in your own 3D printed parts. You can click on the thumbnail to jump that that portion of the guide for immediate recommendations on how to resolve the issue. If you are not able to locate your issues from the thumbnails, feel free to scroll down and read through each section of the guide in more detail. There are plenty of useful tips to learn that can help improve your 3D printed results!
Sagging, drooping, or gaps between the extruded segments of your bridging regions
Each issue will now be listed one-by-one with details about what causes the problem and instructions for troubleshooting it. If you want to read more about a particular section, just click on the plus sign (“+”) to expand the section.
This issue is a very common one for new 3D printer owners, but thankfully, it is also very easy to resolve! If your extruder is not extruding plastic at the beginning of your print, there are four possible causes. We will walk through each one below and explain what settings can be used to solve the problem.
Most extruders have a bad habit of leaking plastic when they are sitting idle at a high temperature. The hot plastic inside the nozzle tends to ooze out of the tip, which creates a void inside the nozzle where the plastic has drained out. This idle oozing can occur at the beginning of a print when you are first preheating your extruder, and also at the end of the print while the extruder is slowly cooling. If your extruder has lost some plastic due to oozing, the next time you try to extrude, it is likely that it will take a few seconds before plastic starts to come out of the nozzle again. If you are trying to start a print after you nozzle has been oozing, you may notice the same delayed extrusion. To solve this issue, make sure that you prime your extruder right before beginning a print so that the nozzle is full of plastic and ready to extrude. A common way to do this in Simplify3D is by including something called a skirt. The skirt will draw a circle around your part, and in the process, it will prime the extruder with plastic. If you need extra priming, you can increase the number of skirt outlines on the Additions tab in Simplify3D. Some users may also prefer to manually extrude filament from their printer using the Jog Controls in Simplify3D’s Machine Control Panel prior to beginning the print.
If the nozzle is too close to the build table surface, there will not be enough room for plastic to come out of the extruder. The hole in the top of the nozzle is essentially blocked so that no plastic can escape. An easy way to recognize this issue is if the print does not extrude plastic for the first layer or two, but begins to extrude normally around the 3rd or 4th layers as the bed continues to lower along the Z-axis. To solve this problem, you can use the very handy G-Code offsets which can be found on the G-Code tab of Simplify3D’s process settings. This allows you to make very fine adjustments to the Z-axis position without needing to change the hardware. For example, if you enter a value of 0.05mm for the Z-axis G-Code offset, this will move the nozzle 0.05mm further away from the print bed. Keep increasing this value by small increments until there is enough room between the nozzle and the build platform for the plastic to escape.
Most 3D printers use a small gear to push the filament back and forth. The teeth on this gear bite into the filament and allow it to accurately control the position of the filament. However, if you notice lots of plastic shavings or it looks like there is a section missing from your filament, then it’s possible that the drive gear has removed too much plastic. Once this happens, the drive gear won’t have anything left to grab onto when it tries to move the filament back and forth. Please see the Grinding Filament section for instructions on how to fix this issue.
If none of the above suggestions are able to resolve the issue, then it is likely that your extruder is clogged. This can happen if foreign debris is trapped inside the nozzle, when hot plastic sits inside the extruder too long, or if the thermal cooling for the extruder is not sufficient and the filament begins to soften outside of the desired melt zone. Fixing a clogged extruder may require disassembling the extruder, so please contact your printer manufacturer before you proceed. We have had great success using the “E” string on a guitar to unclog extruders by feeding it into the nozzle tip, however, your manufacturer should also be able to provide recommendations.
It is very important that the first layer of your print is strongly connected to the printer’s build platform so that the remainder of your part can be built on this foundation. If the first layer is not sticking to the build platform, it will create problems later on. There are many different ways to cope with these first layer adhesion problems, so we will examine several typical causes below and explain how to address each one.
Many printers include an adjustable bed with several screws or knobs that control the position of the bed. If your printer has an adjustable bed and you’re having trouble getting your first layer to stick to the bed, the first thing you will want to verify is that your printer’s bed is flat and level. If the bed is not level, one side of your bed may be too close to the nozzle, while the other side is too far away. Achieving a perfect first layer requires a level print bed. Simplify3D already includes a useful bed leveling wizard that you guide you through the bed leveling process. You can find this wizard by going to Tools > Bed Leveling Wizard, and following the on-screen instructions.
Once your bed has been properly leveled, you still need to make sure that the nozzle is starting at the correct height relative to the build platform. Your goal is to locate your extruder the perfect distance away from the build plate — not too far and not too close. For good adhesion to the build plate, you want your filament to be slightly squished against the build plate. While you can adjust these settings by modifying the hardware, it is typically much easier (and much more precise!) to make these changes from Simplify3D. To do this, click “Edit Process Settings” to open your process settings and then go to the G-Code tab. You can use the Z-Axis global G-Code Offset to make very fine adjustments to your nozzle position. For example, if you enter -0.05mm for the Z-axis G-Code offset, the nozzle will begin printing 0.05mm closer to your build platform. Be careful to only make small adjustments to this setting. Each layer of your part is usually only around 0.2mm thick, so a small adjustment goes a long way!
As you extrude the first layer of plastic on top of the build platform, you want to make sure that plastic can properly bond to the surface before starting the next layer. If you print the first layer too fast, the plastic may not have time to bond to the build platform. For this reason, it is typically very useful to print the first layer at a slower speed so that the plastic has time to bond to the bed. Simplify3D provides a setting for this exact feature. If you click on “Edit Process Settings” and go to the Layer tab, you will see a setting labeled “First Layer Speed”. For example, if you set a first layer speed of 50%, it means that your first layer will print 50% slower than the rest of your part. If you feel that your printer is moving too fast on the first layer, try reducing this setting.
Plastic tends to shrink as it cools from a warm temperature to a cool temperature. To provide a useful example, imagine a 100mm wide part that is being printed with ABS plastic. If the extruder was printing this plastic at 230 degrees Celsius, but it was being deposited onto a cold build platform, it is likely that the plastic would quickly cool down after leaving the hot nozzle. Some printers also include cooling fans that speed up this cooling process when they are being used. If this ABS part cooled down to a room temperature of 30C, the 100mm wide part would shrink by almost 1.5mm! Unfortunately, the build platform on your printer is not going to shrink this much, since it is typically kept at a fairly constant temperature. Because of this fact, the plastic will tend to separate from the build platform as it cools. This is an important fact to keep in mind as you print your first layer. If you notice that the layer seems to stick initially, but later separates from the print bed as it cools, it is possible that your temperature and cooling settings are to blame.
Many printers that are intended to print high-temperature materials like ABS include a heated bed to help combat these problems. If the bed is heated to maintain a temperature of 110C for the entire print, it will keep the first layer warm so that it does not shrink. So if your printer has a heated bed, you may want to try heating the bed to prevent the first layer from cooling. As a general starting point, PLA tends to adhere well to a bed that is heated to 60-70C, while ABS generally works better if the bed is heated to 100-120C. You can adjust these settings in Simplify3D by clicking on “Edit Process Settings” and then selecting the Temperature tab. Choose your heated build platform from the list on the left-hand side and then edit the temperature setpoint for the first layer. You can just double-click on the value to change it.
If your printer has a cooling fan, you may also want to try disabling that cooling fan for the first few layers of your printer so that the initial layers do not cool down too quickly. You can do this by clicking “Edit Process Settings” and going to the Cooling tab. You can adjust the fan speed setpoints on the left-hand side. For example, you may want the first layer to start with the fan disabled and then turn on the fan to full power once you reach the 5th layer. In that case, you will need to add two setpoints into that list: Layer 1 at 0% fan speed, and Layer 5 at 100% fan speed. If you are using ABS plastic, it is common to disable the cooling fan for the entire print, so entering a single setpoint would suffice (Layer 1 at 0% fan speed). If you are working in a breezy environment, you may also want to try to insulate your printer to keep the wind away from your part.
Different plastics tend to adhere better to different materials. For this reason, many printers include a special build platform material that is optimized for their materials. For example, several printers use a BuildTak sheet on the top of their bed that tends to stick very well to PLA. Other manufacturers opt for a heat treated glass bed such as Borosilicate glass, which tends to work very well for ABS when heated. If you are going to print directly onto these surfaces, it is always a good idea to make sure that your build platform is free of dust, grease, or oils before starting the print. Cleaning your print bed with some water or isopropyl rubbing alcohol can make a big difference.
If your printer does not include a special build platform material to help with adhesion, you still have options! Thankfully, there are several types of tape that stick well to common 3D printing materials. Strips of tape can be applied to the build platform surface and easily removed or replaced if you want to print with a different material. For example, PLA tends to stick well to blue painter’s tape while ABS tends to stick better to Kapton tape (otherwise known as Polyimide film). Many users have also had great success using a temporary glue or spray on the top of their build platforms. Hair spray, glue sticks, and other sticky substances tend to work very well if everything else has failed. Feel free to experiment to see what works best for you!
Sometimes you are printing a very small part that simply does not have enough surface area to stick to the build platform surface. Simplify3D includes several options that can help increase this surface area to provide a larger surface to stick to the print bed. One of these options is called a “brim.” The brim adds extra rings around the exterior of your part, similar to how a brim of a hat increases the circumference of the hat. This option can be enabled by going to the “Additions” tab end enabling the “Use Skirt/Brim” option. Simplify3D also allows users to add a raft under their part, which can also be used to provide a larger surface for bed adhesion. If you are interested in these options, please take a look at our Rafts, Skirts, and Brims tutorial which explains things in greater detail.
Each profile in Simplify3D includes settings that are used to determine how much plastic the 3D printer should extrude. However, because the 3D printer does not provide any feedback about how much plastic actually leaves the nozzle, it’s possible that there may be less plastic exiting the nozzle than what the software expects (otherwise known as under-extrusion). If this happens, you may start to notice gaps between adjacent extrusions of each layer. The most reliable way to test whether or not your printer is extruding enough plastic is to print a simple 20mm tall cube with at least 3 perimeter outlines. At the top of the cube, check to see if the 3 perimeters are strongly bonded together or not. If there are gaps between the 3 perimeters, then you are under-extruding. If the 3 perimeters are touching and do not have any gaps, then you are likely encountering a different issue. If you determine that you are under-extruding, there are several possible causes for this, which we have summarized below.
The first thing you want to verify is that the software knows the filament diameter that you are using. You can find this setting by clicking “Edit Process Settings” and going to the Other tab. Check to make sure that this value matches the filament that you purchased. You may even want to measure your filament yourself using a pair of calipers to make sure that you truly have the correct diameter specified in the software. The most common values for the filament diameter are 1.75mm and 2.85mm. Many spools of plastic also include the correct diameter on the packaging.
If your filament diameter is correct, but you are still seeing under-extrusion issues, then you need to adjust your extrusion multiplier. This is a very useful setting in Simplify3D that allows you to easily modify the amount of plastic that is extruded (otherwise known as the flow rate). You can find this setting by clicking “Edit Process Settings” and going to the Extruder tab. Each extruder on your printer can have a unique extrusion multiplier, so if you are trying to modify the flow rate for a specific extruder, make sure to select it from the list on the left to load the settings for that extruder. As an example, if your extrusion multiplier was 1.0 previously and you change it to 1.05, it means you will be extruding 5% more plastic than you were previously. It is typical for PLA to print with an extrusion multiplier near 0.9, while ABS tends to have extrusion multipliers closer to 1.0. Try increasing your extrusion multiplier by 5%, and then reprint the test cube to see if you still have gaps between your perimeters.
The software is constantly working together with your printer to make sure that your nozzle is extruding the correct amount of plastic. This precise extrusion is an important factor in achieving good print quality. However, most 3D printers have no way of monitoring how much plastic is actually extruded. If your extrusion settings are not configured properly, the printer may extrude more plastic than the software expects. This over-extrusion will result in excess plastic that can ruin the outer dimensions of your part. To resolve this issue, there are only a few settings you need to verify in Simplify3D. Please see the Not Extruding Enough Plastic section for a more detailed description. While those instructions are for under-extrusion, you will adjust the same settings for over-extrusion, just in the opposite direction. For example, if increasing the extrusion multiplier helps with under-extrusion, then you should decrease the extrusion multiplier for over-extrusion issues.
To save plastic, most 3D printed parts are created to have a solid shell that surrounds a porous, partially hollow interior. For example, the interior of the part may use a 30% infill percentage, which means that only 30% of the interior is solid plastic, while the rest is air. While the interior of the part may be partially hollow, we want the exterior to remain solid. To do this, Simplify3D allows you to specify how many solid layers you want on the top and bottom of your part. For example, if you were printing a simple cube with 5 top and bottom solid layers, the software would print 5 completely solid layers at the top and bottom of the print, but everything else in the middle would be printed as a partially hollow layer. This technique can save a tremendous amount of plastic and time, while still creating very strong parts thanks to Simplify3D’s great infill options. However, depending on what settings you are using, you may notice that the top solid layers of your print are not completely solid. You may see gaps or holes between the extrusions that make up these solid layers. If you have encountered this issue, here are several simple settings that you can adjust to fix it.
The first setting to adjust is the number of top solid layers that are used. When you try to print a 100% solid layer on top of your partially hollow infill, the solid layer has to span across the hollow air pockets of your infill. When this happens, the extrusions for the solid layer have a tendency to droop or sag down into the air pocket. Because of this, you generally want to print several solid layers at the top of your print to ensure a nice flat, completely solid surface. As a good rule of thumb, you want the solid section at the top of your print to be at least 0.5mm thick. So if you are using a 0.25mm layer height, you would need at least 2 top solid layers. If you are printing at a lower layer height such as 0.1mm, you may need 5 solid layers at the top of your print to achieve the same effect. If you are noticing gaps between the extrusions in your top surface, the first thing you should try is increasing the number of top solid layers. For example, if you noticed the problem using only 3 top solid layers, try printing with 5 top solid layers to see if the problem is improved. Note that additional solid layers will occur within your part dimension and do not add size to the exterior of your part. You can adjust the solid layer settings by clicking “Edit Process Settings” and selecting the Layer tab.
The infill on the inside of your part will act as the foundation for the layers above it. The solid layers at the top of your part will need to print on top of this foundation. If your infill percentage is very low, there will be large air gaps in your infill. For example, if you are using an infill percentage of only 10%, the remaining 90% of the interior of your part would be hollow, and this would create some very large air gaps that the solid layers would need to print on top of. If you have tried increasing the number of top solid layers and you are still seeings gaps in the top of your print, you may want to try increasing your infill percentage to see if the gaps go away. For example, if your infill percentage was previously 30%, try using a 50% infill percentage, as this would provide a much better foundation for the solid layers at the top of your print.
If you have tried increasing the infill percentage and the number of top solid layers, yet you are still seeing gaps in the tops of your print, then you likely have an under-extrusion issue. This means that your nozzle is not extruding as much plastic as the software expects. For a full description of this issue and how to correct it, please read the Not Extruding Enough Plastic section.
Stringing (otherwise known as oozing, whiskers, or “hairy” prints) occurs when small strings of plastic are left behind on a 3D printed model. This is typically due to plastic oozing out of the nozzle while the extruder is moving to a new location. Thankfully, there are several settings within Simplify3D that can help with this issue. The most common setting that is used to combat excessive stringing is something that is known as retraction. If retraction is enabled, when the extruder is done printing one section of your model, the filament will be pulled backwards into the nozzle to act as a countermeasure against oozing. When it is time to begin printing again, the filament will be pushed back into the nozzle so that plastic once again begins extruding from the tip. To ensure retraction is enabled, click “Edit Process Settings” and click on the Extruder tab. Ensure that the retraction option is enabled for each of your extruders. In the sections below, we will discuss the important retraction settings as well as several other settings that can be used to combat stringing, such as the extruder temperature settings.
The most important retraction setting is the retraction distance. This determines how much plastic is pulled out of the nozzle. In general, the more plastic that is retracted from the nozzle, the less likely the nozzle is to ooze while moving. Most direct-drive extruders only require a retraction distance of 0.5-2.0mm, while some Bowden extruders may require a retraction distance as high as 15mm due to the longer distance between the extruder drive gear and the heated nozzle. If you encounter stringing with your prints, try increasing the retraction distance by 1mm and test again to see if the performance improves.
The next retraction setting that you should check is the retraction speed. This determines how fast the filament is retracted from the nozzle. If you retract too slowly, the plastic will slowly ooze down through the nozzle and may start leaking before the extruder is done moving to its new destination. If you retract too quickly, the filament may separate from the hot plastic inside the nozzle, or the quick movement of the drive gear may even grind away pieces of your filament. There is usually a sweet spot somewhere between 1200-6000 mm/min (20-100 mm/s) where retraction performs best. Thankfully, Simplify3D has already provided many pre-configured profiles that can give you a starting point for what retraction speed works best, but the ideal value can vary depending on the material that you are using, so you may want to experiment to see if different speeds decrease the amount of stringing that you see.
Once you have checked your retraction settings, the next most common cause for excessive stringing is the extruder temperature. If the temperature is too high, the plastic inside the nozzle will become less viscous and will leak out of the nozzle much more easily. However, if the temperature is too low, the plastic will still be somewhat solid and will have difficulty extruding from the nozzle. If you feel you have the correct retraction settings, but you are still encountering these issues, try decreasing your extruder temperature by 5-10 degrees. This can have a significant impact on the final print quality. You can adjust these settings by clicking “Edit Process Settings” and selecting the Temperature tab. Select your extruder from the list on the left, and then double-click on the temperature setpoint you wish to edit.
As we discussed above, stringing occurs when the extruder is moving between two different locations, and during that move, plastic starts to ooze out of the nozzle. The length of this movement can have a large impact on how much oozing takes place. Short moves may be quick enough that the plastic does not have time to ooze out of the nozzle. However, long movements are much more likely to create strings. Thankfully, Simplify3D includes an extremely useful feature that can help minimize the length of these movements. The software is smart enough that it can automatically adjust the travel path to make sure that nozzle has a very short distance to travel over an open space. In fact, in many cases, the software may be able to find a travel path that avoids crossing an open space all together! This means that there is no possibility to create a string, because the nozzle will always be on top of the solid plastic and will never travel outside the part. To use this feature, click on the Advanced tab and enable the “Avoid crossing outline for travel movement” option.
Finally, you may also find that increasing the movement speed of your machine can also reduce the amount of time that the extruder can ooze when moving between parts. You can verify what movement speeds your machine is using by clicking on the Speeds tab of your process settings. The X/Y Axis Movement Speed represents the side-to-side travel speed, and is frequently directly related to the amount of time your extruder spends moving over open air. If your machine can handle moving at higher speeds, you may find that increasing this settings can also reduce stringing between parts.
The plastic that exits your extruder may be anywhere from 190 to 240 degrees Celsius. While the plastic is still hot, it is pliable and can easily be formed into different shapes. However, as it cools, it quickly becomes solid and retains its shape. You need to achieve the correct balance between temperature and cooling so that your plastic can flow freely through the nozzle, but it can quickly solidify to maintain the exact dimensions of your 3D printed part. If this balance is not achieved, you may start to notice some print quality issues where the exterior of your part is not as precise and defined as you would like. As you can see in the image on the left, the filament extruded at the top of the pyramid was not able to cool quickly enough to retain its shape. The section below will examine several common causes for overheating and how to prevent them.
The most common cause for overheating is that the plastic is not being cooled fast enough. When this happens, the hot plastic is free to change shapes as it slowly cools. For many plastics, it is much better to quickly cool the layers to prevent them from changing shape after being printed. If your printer includes a cooling fan, try increasing the power of the fan to cool the plastic faster. You can do this by clicking “Edit Process Settings” and selecting the Cooling tab. Simply double-click on the fan speed setpoint you wish to edit. This additional cooling will help the plastic retain its shape. If your printer does not include an integrated cooling fan, you may want to try installing an aftermarket fan or using a small handheld fan to cool down the layers faster.
If you are already using a cooling fan and you are still seeing this issue, you may want to try printing at a lower temperature. If the plastic is extruded at a lower temperature it will be able to solidify faster and retain its shape. Try lowering the print temperature by 5-10 degrees to see if it helps. You can do this by clicking “Edit Process Settings” and selecting the Temperature tab. Simply double-click the temperature setpoint you wish to change. Be careful not to lower the temperature too far, as otherwise the plastic may not be hot enough to extrude through the small opening in your nozzle.
If you are printing each layer very quickly, you might not allow enough time for the previous layer to properly cool before you are trying to deposit the next layer of hot plastic on top of it. This is particularly important for very small parts where each layer only requires a few seconds to print. Even with a cooling fan, you may still need to decrease the printing speed for these small layers to ensure you provide enough time for the layer to solidify. Thankfully, Simplify3D includes a very simple option to do exactly that. If you click on “Edit Process Settings” and select the Speeds tab, you will see a section labeled “Speed Overrides.” This section is used to automatically slow down the printing speed for small layers to ensure they have enough time to cool and solidify before printing the next layer. For example, if you allow the software to adjust the printing speed for layers that take less than 15 seconds to print, the program will automatically slow down the printing speed for these small layers. This is a vital feature for combating these overheating issues.
If you have already tried the 3 items above and you are still having trouble achieving sufficient cooling, there’s one more thing you can try. Create a copy of the part you are trying to print (Edit > Copy/Paste) or import a second object that can be printed at the same time. By printing two objects at once, you can provide more cooling time for each individual part. The hot nozzle will need to move to a different location on the build platform to print the second part, which provides a short relief for your first part to cool down. This is a simple, yet very effective strategy for fixing overheating problems.
Most 3D printers use an open-loop control system, which is a fancy way to say that they have no feedback about the actual location of the toolhead. The printer simply attempts to move the toolhead to a specific location, and hopes that it gets there. In most cases, this works fine because the stepper motors that drive the printer are quite powerful, and there are no significant loads to prevent the toolhead from moving. However, if something does go wrong, the printer would have no way to detect this. For example, if you happened to bump into your printer while it was printing, you might cause the toolhead to move to a new position. The machine has no feedback to detect this, so it would just keep printing as if nothing had happened. If you notice misaligned layers in your print, it is usually due to one of the causes below. Unfortunately, once these errors occur, the printer has no way to detect and fix the problem, so we will explain how to resolve these issues below.
If you are printing at a very high speed, the motors for your 3D printer may struggle to keep up. If you attempt to move the printer faster than the motors can handle, you will typically hear a clicking sound as the motor fails to achieve the desired position. If this happens, the remainder of the print will be misaligned with everything that was printed before it. If you feel that your printer may be moving too fast, try to reduce the printing speed by 50% to see if it helps. To do this, click “Edit Process Settings” and select the Speeds tab. Adjust both the “Default Printing Speed” and the “X/Y Axis Movement Speed.” The default printing speed controls the speed of any movements where the extruder is actively extruding plastic. The X/Y axis movement speed controls the speed of rapid movements where no plastic is being extruded. If either of those speeds are too high, it can cause shifting to occur. If you are comfortable adjusting more advanced settings, you may also want to consider lowering the acceleration settings in your printer’s firmware to provide a more gradual speed up and slow down.
If the layer misalignment continues, even after reducing your print speed, then it is likely due to mechanical or electrical issues with the printer. For example, most 3D printers use belts that allow the motors to control the position of the toolhead. The belts are typically made of a rubber material and reinforced with some type of fiber to provide additional strength. Over time, these belts may stretch, which can impact the belt tension that is used to position the toolhead. If the tension becomes too loose, the belt may slip on top of the drive pulley, which means the pulley is rotating, but the belt is not moving. If the belt was originally installed too tight, this can also cause issues. An overtightened belt can create excess friction in the bearings that will prevent the motors from spinning. Ideal assembly requires a belt that is somewhat tight to prevent slipping, but not too tight to where the system is unable to rotate. If you start noticing issues with misaligned layers, you should verify that your belts all have the appropriate tension, and none appear to be too loose or too tight. If you think there may be a problem, please consult the printer manufacturer for instructions on how to adjust the belt tension.
Many 3D printers also include a series of belts that are driven by pulleys attached to a stepper motor shaft using a small set-screw (otherwise known as a grub screw). These set-screws anchor the pulley to the shaft of the motor so that the two items spin together. However, if the set-screw loosens, the pulley will no longer rotate together with the motor shaft. This means that the motor may be spinning, but the pulley and belts are not moving. When this happens, the toolhead does not get to the desired location, which can impact the alignment of all future layers of the print. So if layer misalignment is a reoccurring problem, you should verify that all of the motor fasteners are properly tightened.
There are also several other common electrical issues that can cause the motors to lose their position. For example, if there is not enough electrical current getting to the motors, they won’t have enough power to spin. It is also possible that the motor driver electronics could overheat, which causes the motors to stop spinning temporarily until the electronics cool down. While this is not an exhaustive list, it provides a few ideas for common electrical and mechanical causes that you may want to check if layer shifting is a persistent problem.
3D printing works by building the object one layer at a time. Each successive layer is printed on top of the previous layer, and in the end this creates the desired 3D shape. However, for the final part to be strong and reliable, you need to make sure that each layer adequately bonds to the layer below it. If the layers do not bond together well enough, the final part may split or separate. We will examine several typical causes for this below and provide suggestions for resolving each one.
Most 3D printing nozzles have a diameter between 0.3-0.5mm. The plastic squeezes through this tiny opening to create a very thin extrusion that can produce extremely detailed parts. However, these small nozzles also create some limitations for what layer heights can be used. When you print one layer of plastic on top of another, you want to make sure that the new layer is being pressed against the layer below it so that the two layers will bond together. As a general rule of thumb, you want to make sure that the layer height you select is 20% smaller than your nozzle diameter. For example, if you have a 0.4mm nozzle, you can’t go too far past a layer height of 0.32mm, or each layer of plastic will not be able to properly bond to the layer beneath it. So if you notice that your prints are separating and the layers are not sticking together, the first thing you should check is your layer height compared to the size of your nozzle. Try reducing the layer height to see if it helps the layers bond together better. You can do this by clicking “Edit Process Settings” and selecting the Layer tab.
Warm plastic will always bond together much better than cold plastic. If you notice that your layers aren’t bonding together and you are certain that your layer height isn’t too large, then it is possible that your filament needs to be printed at a higher temperature to create a strong bond. For example, if you tried to print ABS plastic at 190C, you would likely find that the layers of your part will easily break apart. This is because ABS typically needs to be printed around 220-235C to create a strong bond between the layers of your print. So if you feel this may be the problem, verify that you are using the correct temperature for the filament you have purchased. Try increasing the temperature by 10 degrees to see if the adhesion improves. You can do this by clicking “Edit Process Settings” and selecting the Temperature tab. Simply double-click the temperature setpoint you wish to change.
Most 3D printers use a small drive gear that grabs the filament and sandwiches it against another bearing. The drive gear has sharp teeth that allow it to bite into the filament and push it forward or backward, depending on which direction the drive gear spins. If the filament is unable to move, yet the drive gear keeps spinning, it can grind away enough plastic from the filament so that there is nothing left for the gear teeth to grab on to. Many people refer to this situation as the filament being “stripped,” because too much plastic has been stripped away for the extruder to function correctly. If this is happening on your printer, you will typically see lots of small plastic shavings from the plastic that has been ground away. You may also notice that the extruder motor is spinning, but the filament is not being pulled into the extruder body. We will explain the easiest way to resolve this issue below.
One of the first things you will want to check are the retraction settings for your extruder. If the retraction speed is too fast, or you are trying to retract far too much filament, it may put excessive stress on your extruder and the filament will struggle to keep up. As an easy test, you can try reducing your retraction speed by 50% to see if the problem goes away. If so, you know that your retraction settings may be part of the problem.
If you continue to encounter filament grinding, try to increase the extruder temperature by 5-10 degrees so that the plastic flows easier. You can do this by clicking “Edit Process Settings” and selecting the Temperature tab. Select your extruder from the list on the left and then double-click on the temperature setpoint you wish to change. Plastic will always flow easier at a higher temperature, so this can be a very helpful setting to adjust.
If you continue to encounter filament grinding, even after increasing the temperature, then the next thing you should do is decrease the printing speed. By doing this, the extruder motor will not need to spin as fast, since the filament is extruded over a longer period of time. The slower rotation of the extruder motor can help avoid grinding issues. You can adjust this setting by clicking “Edit Process Settings” and selecting the Speeds tab. Adjust the “Default Printing Speed,” which controls the speed of any movements where the extruder is actively extruding plastic. For example, if you were previously printing at 3600 mm/min (60 mm/s), try decreasing that value by 50% to see if the filament grinding goes away.
If you are still encountering filament grinding after increasing the temperature and slowing down the print speed, then it’s likely your nozzle is partially clogged. Please read the Clogged Extruder section for instructions on how to troubleshoot this issue.
Your 3D printer must melt and extrude many kilograms of plastic over its lifetime. To make things more complicated, all of this plastic must exit the extruder through a tiny hole that is only as big as a single grain of sand. Inevitably, there may come a time where something goes wrong with this process and the extruder is no longer able to push plastic through the nozzle. These jams or clogs are usually due to something inside the nozzle that is blocking the plastic from freely extruding. While this may be daunting the first time it happens, but we will walk through several easy troubleshooting steps that can be used to fix a jammed nozzle.
One of the first things you may want to try is manually pushing the filament into the extruder. Open Simplify3D’s Machine Control Panel and heat your extruder to the appropriate temperature for your plastic. Next, use the Jog Controls tab to extruder a small amount of plastic, for example, 10mm. As the extruder motor is spinning, lightly use your hands to help push the filament into the extruder. In many cases, this added force will be enough to advance the filament past the problem area.
If the filament still isn’t moving, the next thing you should do is unload the filament. Verify that the extruder is heated to the appropriate temperature, and then use Simplify3D’s machine control panel to retract the filament out of the extruder. As before, you may need to apply some additional force if the filament isn’t moving. Once the filament is removed, use a pair of scissors to cut away the melted or damaged portion of the filament. Then reload the filament and see if you are able to extrude with the new, undamaged section of filament.
If you weren’t able to extrude the new section of plastic through the nozzle, then it’s likely you will need to clean out the nozzle before proceeding. Many users have had success heating their extruder to 100C and then manually pulling the filament out (hopefully along with any debris that was inside!). Others prefer to use the E string from a guitar to push the material backwards through the nozzle tip. There are plenty of other methods and each extruder is different, so please consult your printer manufacturer for precise instructions.
If your printer was extruding properly at the beginning of your print, but suddenly stopped extruding later on, there are typically only a few things that could have caused this problem. We will explain each common cause below and provide suggestions for fixing the issue. If your printer was having trouble extruding at the very beginning of the print, please see the Not Extruding at Start of Print section.
This one is pretty obvious, but before checking the other issues, first verify that you still have filament leading into the nozzle. If the spool has run out, you will need to load a new spool before continuing the print.
During a print, the extruder motor is constantly spinning trying to push the filament into the nozzle so that your printer can keep extruding plastic. If you try to print too quickly or you try to extrude too much plastic, this motor may end up grinding away the filament until there is nothing left for the drive gear to grab onto. If your extruder motor is spinning, but the filament is not moving, then this is likely the cause. Please see the Grinding Filament section for more details on how to resolve the issue.
If none of the above causes apply to you, then it is very likely that the extruder is clogged. If this happens in the middle of the print, you may want to check and make sure that the filament is clean and that there is no dust on the spool. If enough dust is attached to the filament, it can cause a clog as it builds up inside the nozzle. There are several other possible causes for a clogged extruder, so please see the clogged extruder description in the Not Extruding at Start of Print section for more details.
The extruder motor has to work incredibly hard during your print. It is constantly spinning back and forth, pushing and pulling plastic back and forth. This quick motion requires quite a bit of current, and if the printer’s electronics do not have sufficient cooling, it can cause the motor driver electronics to overheat. These motor drivers typically have a thermal cutoff that will cause the driver to stop working if the temperature gets too high. If this happens, the X and Y axis motors will be spinning and moving the extruder toolhead, but the extruder motor will not be moving at all. The only way to resolve this issue is to turn off the printer and allow the electronics to cool down. You may also want to add an extra cooling fan if the problem continues.
The infill inside your 3D printed part plays a very important role in the overall strength of your model. The infill is responsible for connecting the outer shells of your 3D print, and must also support the upper surfaces that will be printed on top of the infill. If your infill appears to be weak or stringy, you may want to adjust a few settings within the software to add additional strength to this section of your print.
One of the first settings you should investigate is the infill pattern that is used for your print. You can find this setting by clicking “Edit Process Settings” and going to the Infill tab. The “Internal Fill Pattern” determines what pattern is used for the interior of your part. Some patterns tend to be more solid than others. For example, Grid, Triangular, and Solid Honeycomb are all strong infill patterns. Other patterns like Rectilinear and Fast Honeycomb may sacrifice some strength for faster printing speeds. If you are having trouble producing strong reliable infill, try a different pattern to see if it makes a difference.
The infill is typically printed faster than any other portion of your 3D print. If you try to print the infill too fast, the extruder won’t be able to keep up and you will start to notice under-extrusion on the inside of your part. This under-extrusion will tend to create weak, stringy infill since the nozzle is not able to extrude as much plastic as the software would like. If you have tried several infill patterns, but continue to have problems with weak infill, try reducing the print speed. To do this, click “Edit Process Settings” and select the Speeds tab. Adjust the “Default Printing Speed”, which directly controls the speed that is used for the infill. For example, if you were previously printing at 3600 mm/min (60 mm/s), try decreasing that value by 50% to see if the infill starts to become stronger and more solid.
Another very powerful feature within Simplify3D is the ability to modify the extrusion width that is used for the infill of your part. For example, you could print the outline perimeters with a very fine 0.4mm extrusion width, but transition to a 0.8mm extrusion width for the infill. This will create thicker, stronger infill walls that greatly improve the strength of your 3D printed part. To adjust this setting, click “Edit Process Settings” and select the Infill tab. The “Infill Extrusion Width” is set as a percentage of the normal extrusion width. For example, if you enter a value of 200%, the infill extrusions will be twice as thick as the outline perimeters. One thing to keep in mind when adjusting this setting is that the software must also maintain the infill percentage that you specify. So if you set the infill extrusion width to 200%, the infill will use twice as much plastic for each line. To maintain the same infill percentage, the infill lines must be spaced further apart. For this reason, many users tend to increase their infill percentage after increasing the infill extrusion width.
During your 3D print, the extruder must constantly stop and start extruding as it moves to different portions of the build platform. Most extruders are very good at producing a uniform extrusion while they are running, however, each time the extruder is turned off and on again, it can create extra variation. For example, if you look at the outer shell of your 3D print, you may notice a small mark on the surface that represents the location where the extruder started printing that section of plastic. The extruder had to start printing the outer shell of your 3D model at that specific location, and then it eventually returned to that location when the entire shell had been printed. These marks are commonly referred to as blobs or zits. As you can imagine, it is difficult to join two pieces of plastic together without leaving any mark whatsoever, but there are several tools in Simplify3D that can be used to minimize the appearance of these surface blemishes.
If you start to notice small defects on the surface of your print, the best way to diagnose what is causing them is to watch closely as each perimeter of your part is printed. Does the defect appear the moment the extruder starts printing the perimeter? Or does it only appear later when the perimeter is completed and the extruder is coming to a stop? If the defect appears right away at the beginning of the loop, then it’s possible your retraction settings need to be adjusted slightly. Click on “Edit Process Settings” and go to the Extruders tab. Right below the retraction distance, there is a setting labeled “Extra Restart Distance.” This option determines the difference between the retraction distance when the extruder is stopping and the priming distance that is used when the extruder is restarting. If you notice a surface defect right at the beginning of the perimeter, then your extruder is likely priming too much plastic. You can reduce the priming distance by entering a negative value for the extra restart distance. For example, if your retraction distance is 1.0mm, and the extra restart distance is -0.2mm (note the negative sign), then each time your extruder stops, it will retract 1.0mm of plastic. However, each time the extruder has to start extruding again, it will only push 0.8mm of plastic back into the nozzle. Adjust this setting until the defect no longer appears when the extruder initially begins printing the perimeter.
If the defect does not occur until the end of the perimeter when the extruder is coming to a stop, then there is a different setting to adjust. This setting is called coasting. You can find it right below the retraction settings on the Extruder tab. Coasting will turn off your extruder a short distance before the end of the perimeter to relieve the pressure that is built up within the nozzle. Enable this option and increase the value until you no longer notice a defect appearing at the end of each perimeter when the extruder is coming to a stop. Typically, a coasting distance between 0.2-0.5mm is enough to have a noticeable impact.
The retraction and coasting settings mentioned above can help avoid defects each time the nozzle retracts, however, in some cases, it is better to simply avoid the retractions all together. This way the extruder never has to reverse direction and can continue a nice uniform extrusion. This is particularly important for machines that use a Bowden extruder, as the long distance between the extruder motor and the nozzle makes retractions more troublesome. To adjust the settings that control when a retraction takes place, go to the Advanced tab and look for the “Ooze Control Behavior” section. This section contains many useful settings that can modify the behavior of your 3D printer. As was mentioned in the Stringing or Oozing section, retractions are primarily used to prevent the nozzle from oozing as it moves between different parts of your print. However, if the nozzle is not going to cross an open space, the oozing that occurs will be on the inside of the model and won’t be visible from the outside. For this reason, many printers will have the “Only retract when crossing open spaces” option enabled to avoid unnecessary retractions.
Another related setting can be found in the “Movement Behavior” section. If your printer is only going to retract when crossing open spaces, then it would be beneficial to avoid these open spaces as much as possible. Simplify3D includes an extremely useful feature that can divert the travel path of the extruder to avoid crossing an outline perimeter. If the extruder can avoid crossing the outline by changing the travel path, then a retraction won’t be needed. To use this feature, simply enable the “Avoid crossing outline for travel movement” option.
Another extremely useful feature in Simplify3D is the ability to perform non-stationary retractions. This is particularly useful for bowden extruders that build up a lot of pressure inside the nozzle while printing. Typically when these types of machines stop extruding, the excess pressure is still likely to create a blob if the extruder is standing still. So Simplify3D has added a unique option that allows you to keep the nozzle moving while it performs its retraction. This means you are less likely to see a stationary blob since the extruder is constant moving during this process. To enable this option, we have to adjust a few settings. First, click “Edit Process Settings” and go to the Extruder tab. Make sure that the “Wipe Nozzle” option is enabled. This will tell the printer to wipe the nozzle at the end of each section when it stops printing. For the “Wipe Distance”, enter a value of 5mm as a good starting point. Next, go to the Advanced tab and enable the option labeled “Perform retraction during wipe movement”. This will prevent a stationary retraction, since the printer has now been instructed to wipe the nozzle while it retracts. This is a very powerful feature and a great option to try if you are still having trouble removing these defects from the surface of your print.
If you are still seeing some small defects on the surface of your print, Simplify3D also provides an option that can control the location of these points. Click on “Edit Process Settings” and select the Layer tab. In most cases, the locations of these start points are chosen to optimize the printing speed. However, you also have the ability to randomize the placement of the start points or align them to a specific location. For example, if you were printing a statue, you could align all of the start points to be on the backside of the model so that they were not visible from the front. To do this, enable the “Choose start point that is closest to specific location” option and then enter the XY coordinate where you want the start points to be placed.
Each layer of your 3D printed part is created using a combination of outline perimeters and infill. The perimeters trace the outline of your part creating a strong and accurate exterior. The infill is printed inside of these perimeters to make up the remainder of the layer. The infill typically uses a fast back-and-forth pattern to allow for quick printing speeds. Because the infill uses a different pattern than the outline of your part, it is important that these two sections merge together to form a solid bond. If you notice small gaps between the edges of your infill, then there are several settings you may want to check.
Simplify3D includes a setting that allows you to adjust the strength of the bond between the perimeter outlines and the infill. This setting is called the “Outline overlap” and determines how much of the infill will overlap with the outline to join the two sections together. This setting can be found by going to “Edit Process Settings” and selecting the Infill tab. The setting is based on a percentage of your extrusion width, so that it easily scales and adjusts for different nozzle sizes. For example, if you are using a 20% outline overlap, it means that the software will instruct the printer so that the infill overlaps with 20% of the inner-most perimeter. This overlap helps to ensure a strong bond between the two sections. As an example, if you were previously using an outline overlap of 20%, try increasing that value to 30% to see if the gaps between your perimeters and infill disappear.
The infill for your part is generally printed much faster than the outlines. However, if the infill is printed too fast, it will not have enough time to bond to the outline perimeters. If you have tried increasing the outline overlap, but you are still seeing gaps between your perimeters and infill, then you should try decreasing the print speed. To do this, click “Edit Process Settings” and select the Speeds tab. Adjust the “Default Printing Speed”, which controls the speed of any movements where the extruder is actively extruding plastic. For example, if you were previously printing at 3600 mm/min (60 mm/s), try decreasing that value by 50% to see if the gaps between your perimeters and infill disappear. If the gaps are no longer present at the lower speed, gradually increase the default printing speed until you find the best speed for your printer.
If you are seeing curling issues later on in your print, it typically points to overheating issues. The plastic is extruded at a very hot temperature, and if it does not cool quickly, it may change shape over time. Curling can be prevented by rapidly cooling each layer so that it does not have time to deform before it has solidified. Please read the Overheating section for a more detailed description of this issue and how to resolve it. If you are noticing the curling at the very beginning of your print, please see the Print Not Sticking to the Bed section to address first layer issues.
One of the benefits of 3D printing is that each part is constructed one layer at a time. This means that for each individual layer, the nozzle can freely move to any portion of your print bed, since the part is still being constructed down below. While this provides for very fast printing times, you may notice that the nozzle leaves a mark when it travels on top of a previously printed layer. This is typically most visible on the top solid layers of your part. These scars and marks occur when the nozzle tries to move to a new location, but ends up dragging across previously printed plastic. The section below will explore several possible causes for this and provide recommendations for what settings can be adjusted to prevent it from happening.
One of the first things you should verify is that you are not extruding too much plastic. If you extrude too much plastic, each layer will tend to be slightly thicker than intended. This means that when the nozzle tries to move across each layer, it may drag through some of the excess plastic. Before you look at any other settings, you should make sure that you are not extruding too much plastic. Please read the Extruding Too Much Plastic section for more details.
If you know you are extruding the correct amount of plastic, but are still having trouble with the nozzle dragging across your top surface, then it might be worth looking at the vertical lift settings in Simplify3D. Enabling this option will cause the nozzle to lift up a set distance above the previously printed layer before moving to a new location. When it arrives at its final location, the nozzle will lower back down to prepare for printing. By moving at an elevated height, this can avoid the nozzle scratch on the top surface of your print. To enable this option, click “Edit Process Settings” and select the Extruder tab. Make sure that retraction is enabled, and then set the “Retraction Vertical Lift” to the distance that you would like the nozzle to raise. For example, if you enter 0.5mm, the nozzle will always raise up 0.5mm before moving to a new location. Please note that this vertical lift will only occur when the nozzle is performing a retraction. If you want to ensure that a retraction is taking place for every single move that the printer does, click on the Advanced tab and make sure that “Only retract when crossing open spaces” and “Minimum travel for retraction” are disabled.
When building a 3D printed part, each layer relies on the foundation from the layer below. However, the amount of plastic that is used for the print is also a concern, so a balance must be achieved between the strength of the foundation and the amount of plastic that is used. If the foundation is not strong enough, you will start to see holes and gaps between the layers. This is typically most obvious in the corners, where the size of the part is changing (for example, if you were printing a 20mm cube on top of a 40mm cube). When you transition to the smaller size, you need to make sure that you have a sufficient foundation to support the sidewalls of the 20mm cube. There are several typical causes for these weak foundations. We will discuss each one below and present the settings that can be used in Simplify3D to improve the print.
Adding more outline perimeters to your part will greatly improve the strength of the foundation. Because the interior of your part is typically partially hollow, the thickness of the perimeter walls has a significant effect. To adjust this setting, click “Edit Process Settings” and click on the Layer tab. For example, if you were previously printing with two perimeters, try the same print with four perimeters to see if the gaps disappear.
Another common cause for a weak foundation is not having enough solid layers for the top surfaces of your print. A thin ceiling will not be able to adequately support the structures that are printed on top of them. This setting can be adjusted by clicking “Edit Process Settings” and selecting the Layer tab. If you were previously using only two top solid layers, try the same print with four top solid layers to see if the foundation is improved.
The final setting you should check is the infill percentage used for your print, illustrated by a slider under the Process Settings or found under the Infill tab. The top solid layers will be built on top of the infill, so it is important that there is enough infill to support these layers. For example, if you were previously using a infill percentage of 20%, try increasing that value to 40% to see if the print quality improves.
The sides of your 3D printed part are composed of hundreds of individual layers. If things are working properly, these layers will appear to be a single, smooth surface. However, if something goes wrong with just one of these layers, it is usually clearly visible from the outside of the print. These improper layers may appear to look like lines or ridges on the sides of your part. Many times the defects will appear to be cyclical, meaning that the lines appear in a repeating pattern (i.e. once every 15 layers). The section below will look at several common causes for these issues.
The most common cause for this issue is poor filament quality. If the filament does not have very tight tolerances, then you will notice this variation on the side walls of your print. For example, if your filament diameter varied by just 5% over the length of the spool, the width of the plastic extruded from the nozzle could change by as much as 0.05mm. This extra extrusion will create a layer that is wider than all the others, which will end up looking like a line on the side of the print. To create a perfectly smooth side wall, your printer needs to be able to produce a very consistent extrusion which requires high-quality plastic. For other possible causes of variation, please read the Inconsistent Extrusion section.
Most 3D printers use a PID controller to regulate the temperature of the extruder. If this PID controller is not tuned properly, the temperature of the extruder may fluctuate over time. Due to the nature of how PID controllers work, this fluctuation is frequently cyclical, meaning that the temperature will vary with a sine wave pattern. As the temperature gets hotter, the plastic may flow differently than when it is cooler. This will cause the layers of the print to extrude differently, creating visible ridges on the sides of your print. A properly tuned printer should be able to maintain the extruder temperature within +/-2 degrees. During your print, you can use Simplify3D’s machine control panel to monitor the temperature of your extruder. If it is varying by more than 2 degrees, you may need to recalibrate your PID controller. Please consult your printer manufacturer for exact instructions on how to do this.
If you know that inconsistent extrusion and temperature variation are not to blame, then there may be a mechanical issue that is causing lines and ridges on the sides of your print. For example, if the print bed wobbles or vibrates while printing, this can cause the nozzle position to vary. This means that some layers may be slightly thicker than others. These thicker layers will produce ridges on the sides of your print. Another common issue is a Z-axis threaded rod that is not being positioned properly. For example, due to backlash issues or poor motor controller micro-stepping settings. Even a small change in the bed position can have a major impact on the quality of each layer that is printed.
Ringing is a wavy pattern that may appear on the surface of your print due to printer vibrations or wobbling. Typically, you will notice this pattern when the extruder is making a sudden direction change, such as near a sharp corner. For example, if you were printing a 20mm cube, each time the extruder changes to printing a different face of the cube, it would need to change directions. The inertia of the extruder can create vibrations when these sudden direction changes occur, which will be visible of the print itself. We will look at the most common ways to address ringing, by examining each cause in the list below.
The most common cause for ringing is that your printer is trying to move too fast. When the printer suddenly changes direction, these quick movements will create additional force that can cause the lingering vibrations. If you feel that your printer may be moving too fast, try to reduce the printing speed. To do this, click “Edit Process Settings” and select the Speeds tab. You will want to make adjustments to the “Default Printing Speed” and the “X/Y Axis Movement Speed”. The first controls the speed of any movements where the extruder is actively extruding plastic, while the second controls the speed of rapid movements where no plastic is being extruded. You may need to adjust both settings to see an effect.
The firmware that runs on your 3D printer’s electronics typically implements acceleration controls to help prevent sudden direction changes. The acceleration settings will cause the printer to slowly ramp up in speed and then to slowly decelerate before changing directions. This functionality is vital for preventing ringing. If you are comfortable working with your printer’s firmware, you may even want to try decreasing the acceleration settings so that the speed changes more gradually. This can help reduce ringing even further.
If nothing else has been able to resolving the ringing issues, then you may want to look for mechanical issues that could be causing the excessive vibrations. For example, there could be a loose screw or a broken bracket that is allowing excessive vibrations to occur. Watch your printer closely while it is running and try to identify where the vibrations are coming from. We’ve had many users that eventually traced these issues back to mechanical problems with the printer, so it’s worth checking if none of the suggestions above were able to help.
Because your 3D printer includes a fixed size nozzle, you may encounter issues when printing very thin walls that are only a few times larger than the nozzle diameter. For example, if you were trying to print a 1.0mm thick wall with a 0.4mm extrusion width, you may need to make some adjustments to ensure your printer creates a completely solid wall and does not leave a gap in the middle. Simplify3D already includes several dedicated settings to help with thin wall printing, so we will describe the relevant settings below.
The first settings that you need to verify are the dedicated thin wall settings that Simplify3D includes. To view these settings, click “Edit Process Settings” and select the Advanced tab. The software includes several different options for the Internal Thin Wall Type. The default option typically uses something called “gap fill” to fill the small gaps between your thin walls. This will create a back-and-forth infill pattern that adjusts to fill the space between these thin gaps. However, the software also includes another useful option that can fill these thin walls with a single pass. To enable this option, change the Internal Thin Wall Type to “Allow single extrusion fill”. This will use a dynamic single extrusion that will adjust in size to perfectly fill the gap between these walls. For more information about single extrusion options, click here to view our detailed article on the subject.
In some cases, you may find that you have better luck changing the size of the plastic that is extruded from the nozzle. For example, if you were printing a 1.0mm thick wall, you could achieve a fast and strong print if your nozzle was setup to create a 0.5mm extrusion. This works best for parts that have fairly consistent wall thicknesses. You can adjust the extrusion width that the software creates by clicking “Edit Process Settings” and selecting the Extruders tab. Choose a manual extrusion width and enter a value of your choosing.
Most 3D printers have a fixed nozzle size that determines the part resolution in the XY direction. Popular nozzle sizes are 0.4mm or 0.5mm in diameter. While this works well for most parts, you may start to encounter issues when trying to print extremely thin features that are smaller than the nozzle size. For example, if you were trying to print a 0.2mm thick wall with a 0.4mm diameter nozzle, you may notice that this thin wall does not show up in the Simplify3D preview. If you frequently need to print extremely thin features, we will explain the best options to consider for these micro-sized prints.
Simplify3D includes a specialty printing mode specifically for very thin walls and exterior features. To enable this special mode, click “Edit Process Settings”, go to the Advanced tab, and change the External Thin Wall Type to “Allow single extrusion walls”. After you save these settings, if you return to the Simplify3D preview, you will notice that many of these thin features are now printed using these specialty single extrusions. For more information about single extrusion options, click here to view our detailed article on the subject.
If you are still having issues printing these thin features, another option is to redesign the part so that it only includes features that are larger than your nozzle diameter. This typically involves editing the 3D model in the original CAD package to modify the size of the small features. Once you have thickened the small features, you can re-import the model into Simplify3D to verify that your printer is capable of reproducing the 3D shape you created.
In many cases, you are not able to modify the original 3D model. For example, it may be a part that someone else designed or one that you downloaded from the internet. In this case, you may want to consider obtaining a second nozzle for your 3D printer that allows it to print smaller features. Many printers have a removable nozzle tip, which makes these aftermarket adjustments quite easy. For example, many users purchase a 0.3mm nozzle as well as a 0.5mm nozzle to provide two options. Consult your printer manufacturer for exact instructions on how to install a smaller nozzle tip size.
For your printer to be able to create accurate parts, it needs to be capable of extruding a very consistent amount of plastic. If this extrusion varies across different parts of your print, it is going to affect the final print quality. Inconsistent extrusion can usually be identified by watching your printer closely as it prints. For example, if the printer is printing a straight line that is 20mm long, but you notice that the extrusion seems rather bumpy or seems to vary in size, then you are likely experiencing this issue. We have summarize the most common causes for inconsistent extrusion, and explained how each one can be addressed.
The first thing you should check is the spool of plastic that is feeding into your printer. You need to make sure that this spool is able to rotate freely and that the plastic is easily being unwound from the spool. If the filament becomes tangled, or the spool has too much resistance to spin freely, it will impact how evenly the evenly the filament is extruded through the nozzle. If your printer includes a Bowden tube (a small hollow tube that the filament is routed through), you should also check to make sure that the filament can easily move through this tube without too much resistance. If there is too much resistance in the tube, you may want to try cleaning the tube or applying some lubrication inside the tube.
If the filament is not tangled and can easily be pulled into the extruder, then the next thing to check is the nozzle itself. It is possible that there is some small debris or foreign plastic inside the nozzle that is preventing proper extrusion. An easy way to check this is to use Simplify3D’s machine control panel to manually extrude some plastic from the nozzle. Watch to make sure that the plastic is extruding evenly and consistently. If you notice problems, you may need to clean the nozzle. Please consult your manufacturer for instructions on how to properly clean the inside of the nozzle.
If the filament is spinning freely and the extruder is not clogged, it may be useful to check a few settings within Simplify3D. For example, if you are trying to print at an extremely low layer height, such as 0.01mm, there is very little room for the plastic to exit the nozzle. This gap below the nozzle is only 0.01mm tall, which means that the plastic may have a difficult time exiting the extruder. Double check to make sure you are using a reasonable layer height for your printer. You can view this setting by clicking “Edit Process Settings” and selecting the Layer tab. If you are printing at a very small layer height, try increasing the value to see if the problem goes away.
Another setting to check within Simplify3D is the extrusion width that you have specified for your extruder. You can find this setting by clicking “Edit Process Settings” and going to the Extruder tab. Each extruder can have its own unique extrusion width, so make sure you select the appropriate extruder from the list of the left to view the settings for that specific extruder. If you extrusion width is significantly smaller than your nozzle diameter, this may cause extrusion issues. As a general rule of thumb, the extrusion width should be within 100-150% of the nozzle diameter. If your extrusion width is far below the nozzle diameter (for example, a 0.2mm extrusion width for a 0.4mm nozzle), then your extruder won’t be able to push a consistent flow of filament.
One of the most common causes for inconstant extrusion that we have not mentioned yet is the quality of the filament that you are printing with. Low quality filament may contain extra additives that impact the consistency of the plastic. Others may have an inconsistent filament diameter, which will also cause inconsistent extrusion. Finally, many plastics also have a tendency to degrade over time. For example, PLA tends to absorb moisture from the air, and over time, this will cause the print quality to degrade. This is why many spools of plastic include a desiccant in the packaging to help remove any moisture from the spool. If you think your filament may be at fault, try swapping the spool for a new, unopened, high-quality spool to see if the problem goes away.
If you have verified everything above and are still having problems with inconsistent extrusion, then you may want to check for mechanical issues with your extruder. For example, many extruders use a drive gear with sharp teeth that bite into the filament. This allows the extruder to move the filament back and forth easily. These extruders also typically include an adjustment that changes how hard the drive gear is pressed into the filament. If this setting is too loose, the drive gear teeth won’t cut far enough into the filament, which impacts the extruder’s ability to accurately control the position of the filament. Check with your manufacturer to see if your printer has a similar adjustment.
As you start printing larger models, you may start to notice that even though the first few layers of your part successfully adhered to the bed, later on the part begins to curl and deform. This curling can be so severe that it actually causes part of your model to separate from the bed, and may cause the entire print to eventually fail. This behavior is particular common when printing very large or very long parts with high temperature materials such as ABS. The main reason for this problem is the fact that plastic tends to shrink as it cools. For example, if you printed an ABS part at 230C and then allowed it to cool to room temperature, it will shrink by almost 1.5%. For many large parts, this could equate to several millimeters of shrinkage! As the print progresses, each successive layer will deform a bit more until the entire part curls and separates from the bed. This can be a challenging issue to solve, but we have several helpful suggestions to get you started.
Many machines come equipped with a heated bed that can help keep the bottom layers of your part warm throughout the print. For materials such as ABS, it is common to set the heated bed temperature to 100-120C, which will significantly reduce the amount of plastic shrinkage in these layers. To adjust your heated bed temperature, click on “Edit Process Settings”, select the Temperature tab, and then choose your Heated Bed from the list on the left-hand side. You can double-click on the temperature setpoint to edit the value.
By now, you probably realize that cooling can be a problem for parts that tend to warp. For this reason, many users prefer to disable any external cooling fans entirely when printing with materials such as ABS. This allows all of the layers to stay warm for a longer period of time, increasing your chance of success. You can verify your fan speed settings by clicking on the Cooling tab of your process settings in Simplify3D.
While a heated bed can keep the bottom layers of your part warm, it may struggle to keep the upper layers of the part from contracting once you start printing taller and taller objects. In this situation, you may find it useful to place your printer inside of an enclosure that can help regulate the temperature of the entire build volume. Some machines may already include an external enclosure specifically for this reason. If your machine does include a heated enclosure, make sure to keep the doors closed during the print, which will keep the heat from escaping.
If you have already tried all of the other suggestions, but your parts are still curling later on in the print, then you can also try including a brim or a raft with your print. These features will help hold the edges down and may warp less, since they are typically only a few layers tall. If you want to learn more about these options, please read our tutorial on Rafts, Skirts and Brims.
One of the major benefits of Simplify3D is the ability to create innovative support structures which allow you to create incredibly complex parts that would be hard to manufacture otherwise. For example, if you have a steep overhang or part of your model with nothing below it, then a support structure can provide a foundation for these layers. The support structures created by Simplify3D are disposable and can be easily separated from the final part. However, depending on your settings, you may find that some adjustments are needed to perfect the surface quality on the underside of your parts, right above the support structure foundation. We will explain the key settings below and how they can affect your prints.
The overhang performance of your printer can be greatly improved by lowering your layer height. For example, if you reduced your layer height from 0.2mm to 0.1mm, your printer will create twice as many layers, which allows your printer to take smaller steps when creating an overhang. For this reason, your may find that you need support structures for any overhang above 45 degrees when using a 0.2mm layer height, but your overhang performance may improve to 60 degrees if you lower your layer height to 0.1mm. This has the obvious advantage of decreasing your print time and reducing the amount of support structures required for the print, but it will also allow you to create a smoother surface on the underside of your parts. If you find that you need to increase the print quality in this area, this is one of the first settings you will want to adjust.
Just like the interior of your part, you can also adjust the density of your support structures by changing the Support Infill Percentage. It is common to use a value around 20-40%, but you may find that you need to increase this value if the bottom layers of your part are drooping too much. Many users also prefer to use Dense Support Structures for this task, as they allow you to use a lower density for the majority of your supports, and only use a higher infill percentage near the very top of the support structures.
Creating removable support structures involves a fine balance between the amount of support provided to the model, and how easy the supports are to remove. If you provide too much support to the model, the support structures may start to bond to the part, making them difficult to separate. If you provide very little support, the disposable support structures will be easy to remove, but the part may not have enough of a foundation to print successfully. Simplify3D allows your to customize the separation settings, so that you can choose the correct balance between these different factors. The first setting you will want to check is the Upper Vertical Separation Layers. This setting determines how many empty layers are left between the support structures and the part. For example, if you are printing your support structures with the same material as your part, it is common to use at least 1-2 vertical separation layers. Otherwise, if you used 0 separation layers and you are printing everything with the same material, the supports may bond to the part and can become difficult to remove. So this is one of the first settings you want to adjust as you try to perfect your print quality.
The next separation setting you should check is the Horizontal Offset from your part. This setting controls the side-to-side distance between your part and the support structures. So while the Vertical Separation Layers can help keep the top of your supports from bonding to the bottom of your part, the Horizontal Offset will keep the sides of your supports from bonding to the side of your model. It is common to use a value between 0.2-0.4mm for this setting, but you may need to experiment and see what works best for your specific extruder and filament.
If your machine comes with 2 or more extruders, you can achieve a significant improvement by using a different material for your support structures. For example, it is quite common to print parts in PLA using water dissolvable PVA for the supports. Because the model and support structures are printed with different materials, they won’t bond together as easily, which allows you to do a better job of supporting the part. If you are using a different material for the support structures, you can frequently decrease your Upper Vertical Separation Layers to zero, and reduce your Horizontal Offset from the part to around 0.1mm. If you are interested in learning more about this technique, you can watch a more detailed video about the process here.
The dimensional accuracy of your 3D printed parts can be extremely important if you are creating large assemblies or parts that need to precisely fit together. There are many common factors that can affect this accuracy such as under or over-extrusion, thermal contraction, filament quality, and even the first layer nozzle alignment. Simplify3D includes several tools to help cope with these common issues, so we will explain each one in more detail below.
Settings for your first layer can have an impact on dimensional accuracy. If your nozzle is too high or too low for the first layer of your print, it can drastically affect the next 10-20 layers of the part. For example, if you are printing a 0.2mm thick layer, but your nozzle is only positioned 0.1mm away from the bed, then this extra plastic may create a first layer that is a bit too large. Future layers can also be affected by the extra plastic on this layer, which creates several oversized layers at the bottom of the part. So before you spend too much time trying to perfect the dimensional accuracy of your prints, you need to verify that your measurements are not being affected by the first layer position. One common way to do this is by printing a model with 50-100 layers and then only measuring the top 20 or so layers. These top layers are far away from the very first layer that was printed on the bed, so it minimizes the impact of nozzle positioning. Before proceeding to the sections below, make sure that your measurements follow these guidelines.
Now that you know you are using accurate measurements that are not affected by the first layer position, the next setting you want to verify is your extrusion multiplier. This setting affects the flow rate for the entire print. If the extrusion multiplier is too low, you may start to see gaps between perimeters, holes in your top surfaces, and parts that are smaller than their intended size. If your extrusion multiplier is too high, you may notice top layers that tend to bulge upwards and parts that are larger than intended. So again, before proceeding to the sections below you will want to verify that your extrusion multiplier is properly calibrated. For more advice on these topics, please see the Under-Extrusion and Over-Extrusion sections.
If you have completed the steps above and the prints are still not sized correctly, Simplify3D offers the ability to precisely offset the edges of your print to account for these differences. This setting is labeled “Horizontal size compensation” and can be found on the Other tab of your Process Settings. For example, setting this value to -0.1mm will shrink your model by 0.1mm in the X and Y directions. This setting works best when the dimensional error is consistent, even when printing models of different sizes. For example, if the part is always 0.1mm too large, regardless of if the model is 20mm wide or 100mm wide, then this setting can easily account for that difference.
If you notice that the dimensional error tends to increase as you print larger parts, then there is a different setting you can adjust. For example, if your print was 0.1mm too small for a 20mm wide part, but increased to 0.5mm too small for a 100mm wide print, then it is likely the problem may be due to thermal contraction. This can be a common issue for high temperature materials like ABS, since plastic tends to shrink as it cools. Simplify3D includes several options to help with this. First, you need to determine the shrinkage percentage. In the above example, the part is shrinking by 0.1mm over a 20mm print, so the shrinkage percentage is 0.1 / 20 = 0.5%. The easiest way to fix this error is to double-click on your model in the Simplify3D interface and set the scale to 100.5%. If you find yourself making these changes consistently, you can also setup an Import Action to perform this scaling automatically each time you import a new model. Please see this video for more details about creating Import Actions.
Bridging is a term that refers to plastic that needs to be extruded between two points without any support from below. For larger bridges, you may need to add support structures, but short bridges can typically be printed without any supports to save material and print time. When you are bridging between two points, the plastic will be extruded across the gap and then quickly cooled to create a solid connection. To get the best bridging results, you will need to make sure that your printer is properly calibrated with the best settings for these special segments. If you notice sagging, drooping, or gaps between the extruded segments, you may need to adjust your settings for the best results. We will cover each of the areas that you want to address to make sure your can print the best bridges possible on your 3D printer.
Bridging segments are identified with a special color in the Simplify3D preview. Click “Prepare to Print” to enter the Preview Mode and then change the coloring mode on the left-hand side to “Feature Type”. This will use a different color for each feature type, with bridging regions shown in yellow. Use the sliders at the bottom of the preview to scroll to the layer where you expect to see bridging extrusions and verify that these lines are shown in yellow. If the bridging area is not shown in yellow, there are a two settings you will want to check. Exit the preview, click “Edit Process Settings”, and go to the Other tab to view your Bridging settings. The first option in this section is the “Unsupported area threshold”. This allows the software to ignore very small bridging areas and focus on the larger bridging regions that may need special settings. If you think your bridging area is not being included, make sure that the area of your bridging region is larger than this threshold value. The second setting to check is towards the bottom of this list. By default, Simplify3D uses special perimeter settings for any perimeters that are printed as part of a bridging region, but you can also choose to use bridging settings for these regions if you wish. To do this, enable the “Apply bridging settings to perimeters” option, save your settings, and then return to the Simplify3D preview to verify your changes.
Simplify3D will automatically calculate the best infill direction to use for your bridging regions. For example, if you are bridging between two pillars aligned on the X-axis, the software will automatically change the infill direction for that area to ensure the infill is also being extruded along the X-axis. This greatly improves your odds of success, so if you notice that you are getting poor bridging results, you want to double-check to make sure the infill is oriented in the correct direction. If you have already verified that your bridging region is properly identified as a yellow bridging region in Simplify3D, then this change should happen automatically. If you ever want to try a different infill angle for these bridging layers, you can also do this by enabling the “Use fixed bridging angle” option in your process settings.
The bridging regions in Simplify3D are printed with special extrusion, speed, and cooling settings to achieve optimal performance. The extrusion and speed adjustments for these regions can be found on the Other tab of your process settings. Typically, you will want to set the “Bridging extrusion multiplier” to 100% or more, as lower values may have trouble properly sealing the bottom of these surfaces. The “Bridging speed multiplier” may require some experimentation, as some printers will perform better with slow bridging, while others get better results by moving quickly. Finally, you can find the bridging fan speed settings on the Cooling tab of your process settings. Typically, you will want to set the “Bridging fan speed override” to a large value to make sure the bridges are cooled as quickly as possible. Experiment with these settings to find the best combination for your specific 3D printer and filament. There are many bridging test models available that can help with this calibration.
In the event that you are unable to get the results you want after tuning the settings mentioned above, you may find that adding support structures will allow you to achieve the best quality. The support structures will provide an extra foundation for the bridging regions, greatly improving their odds of success. You can enable support generation for the entire model, or use Simplify3D’s customizable support structures for extra control. Please see this video for more details about using custom support structures.
Congratulations! You’ve reached the end of our list for the most common print quality issues that you are likely to encounter with 3D printing. If you are experiencing an issue that was not mentioned in this guide, there are still plenty of ways that you can get help and advice. A great place to start is the Simplify3D User Community. You can search for posts from others users with the same issue, or post pictures of your prints and receive suggestions from other experienced users. If you would rather speak with our team directly, you can also Contact Our Support Staff and we would be happy to assist you.