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Troubleshooting Guide to 14 Common 3D Printing Problems

3D printing problems

Frustrated with Fused Filament Fabrication? Read our 3D printer troubleshooting guide to the most common 3D printing problems and their solutions.

It’s amazing what your 3D printer can produce. But we’ve all had those infuriating moments when, despite everything, a seemingly simple model just refuses to print successfully.

You’ve checked the model, seen countless others print it without issue, but try as you might it just won’t print. What is it that keeps going wrong?

Here at ALL3DP, we’ve had our fair share of print failures. But the upside to those failures is that we’ve become finely tuned to recognizing and solving many common 3D printing problems.

Direct from our 3D printer troubleshooting experience, we’ve collected together 12 of the most common 3D printing problems we’ve had and replicated them here.

This article will help you to quickly diagnose your 3D printing issues, and find the solution with our 3D printer troubleshooting guide. Discover how and when these 3D printing problems occur, and the steps you can take to avoid them in future.

3D Printing Problems: Overview

  1. Warping
  2. Elephant Foot
  3. More First Layer Problems
  4. Layer Misalignment
  5. Missing Layers
  6. Cracks In Tall Objects
  7. Pillowing
  8. Stringing
  9. Under-Extrusion
  10. Over-Extrusion
  11. Shifting Layers
  12. Blocked Bowden Nozzle
  13. Snapped Filament
  14. Stripped Filament

3D Printing Problems #1: Warping

3D Printing Problems: Warping

What’s the 3D Printing Problem?

At the base of the model, the print bends upwards until it’s no longer level with the print platform. This can also result in horizontal cracks in upper parts.

What’s Causing this 3D Printing Problem?

Warping is common as it’s caused by a natural characteristic of the plastic. As the ABS or PLA filament cools it starts to contract very slightly; the problem of warping arises if the plastic is cooled too quickly.

3D Printer Troubleshooting: Warping

  1. Use a heated print platform. The easiest solution is to use a heated print platform and to set the temperature to a point just below the plastics melting point. This is called the “glass transition temperature”. If you get that temperature right then the first layer will stay flat on the print platform. The print platform temperature is often set by the slicer software. You’ll normally find the recommended temperature for your filament printed on the side of the packaging or on the spool.
  2. Apply glue. If you still find your print lifting at the edges then apply a tiny amount of stick glue evenly on the bed to increase adhesion.
  3. Try a different platform type. Change your print bed to one that offers better adhesion. Manufacturers such as Lulzbot use a PEI (Polyetherimide) print surface that offers excellent adhesion without glue. XYZPrinting supply a textured tape in the box with some of their printers, basically a large sheet of masking tape, and again adding this works excellently, although only with nonheated print platforms. Zortrax 3D printers have a perforated print bed, models weld themselves to this surface eliminating the issue completely.
  4. Level the Print platform. Print platform calibration can be another cause, run through the calibration process to check that the bed is level and nozzle height is correct.
  5. Increase contact. Increasing the contact between the model and bed is an easy fix and most print software has the option to add rafts or platforms.
  6. Adjust advanced temperature settings. If all else fails then you’ll need to take a look at your advanced print settings both on your printer and in your print software. Try increasing the print bed temperature by increments of 5 degrees.
    In the slicer software take a look at the fan cooling, this is usually set so the cooling fans switch to full power at a height of around 0.5mm, try extending this to 0.75 to give the base layers a little more time to cool naturally.
    Even if your printer has a heated print platform, it’s always recommended that you use glue and regularly calibrate the bed level.

3D Printing Problem Checklist: Warping

  • Use a heated print platform
  • Add Stick glue to the print platform
  • Swap from glass to an adhesive print bed
  • Calibrate print bed
  • Add platforms or rafts
  • Adjust advance the temperature and fan settings

Back to overview

3D Printing Problems #2: Elephant Foot

3D Printing Problems: Elephant Foot

What’s the 3D Printing Problem?

The base of the model is slightly bulging outwards, otherwise known as “elephant foot”

What’s Causing this 3D Printing Problem?

This ungainly effect can also be caused by the weight of the rest of the model pressing down the first layers when the lower layers haven’t had time to cool back into a solid – particularly when your printer has a heated bed.

3D Printer Troubleshooting: Elephant Foot

  1. The right balance. To stop elephant foot appearing in your 3D prints the base layers of the model need to be cooled sufficiently so that they can support the structure above, but if you apply too much cooling to the base layers you can create warping. Getting the balance right can be tricky, start by lowering the temperature of the print platform by intervals of 5 degrees, (within +/- 20 degrees of the recommended temperature). If your  Bottom / Top Thickness is set to 0.6mm then start the fan after the fan at a slightly lower height.
  2. A level base. More often than not the majority of print issues can be traced back to the level of the print platform. Each printer has a slightly different technique for print platform leveling. Start by using your printers manufacturers recommended procedure. Then print a calibration cube and just watch how the filament is laid down. From printing of the cube you should be able to see if the filament is being laid down evenly, if the nozzle is too close to the print platform and scraping through the molten filament or too high and causing the filament to blob.
  3. Raise the nozzle. Just raising the height of the nozzle slightly can often help, but be careful too high and it won’t stick to the platform.
  4. Chamfer the base. If all else fails then another option is to chamfer the base of your model. Of course, this is only possible if you have either designed the model yourself or you have access to the original file. Start with a 5mm and 45º chamfer, and experiment to get the best result.

3D Printing Problem Checklist: Elephant Foot

  • Balance print platform temperature and fan speed
  • Level the print platform
  • Check the nozzle height
  • Chamfer the model base

Back to overview

3D Printing Problems #3: More First Layer Problems

3D Printing Problems: More First Layer Problems

What’s the 3D Printing Problem?

The first layer does not stick properly, and some parts come loose. There are unwanted lines at the bottom.

What’s Causing this 3D Printing Problem?

These 3D printing problems are typical signs that the print bed hasn’t been leveled properly. If the nozzle is too far away from the bed, the bottom surface often shows unwanted lines, and/or the first layer does not stick. If the nozzle is too close, blobs may be the result.

Also important: the print bed has to be as clean as possible. Fingerprints on the plate can prevent the first layer from sticking to the plate.

3D Printer Troubleshooting: More First Layer Issues

  1. Level the print bed. Every printer has a different process for print platform leveling, some like the latest Lulzbots utilize an extremely reliable auto leveling system, others such as the Ultimaker have a handy step-by-step approach that guides you through the adjustment process and then there’s the Prusa i3 that takes skill and determination.
  2. Adjust the nozzle height. If the nozzle is too high then the filament won’t stick to the platform, to low and the nozzle will actually start to scrape the print off.
  3. Clean the print platform. Every so often it’s a good idea to give the glass print platform a good clean, especially if you apply glue. The grease from your fingerprints and the excessive build up of glue deposits can all contribute to the nonstickiness of the print platform.
  4. Add glue. Applying a thin layer of glue to the print platform will help add a little more adhesion if you do this make sure you give the bed a clean at regular intervals as the over application of glue can have the reverse of the desired effect.
  5. Textured sheet for cold print beds. On cold print platforms, a common solution is to apply a stick-on film or sheet that increases the adhesive properties of the print platform.

3D Printing Problem Checklist: More First Layer Issues

  • Level the print platform
  • Check nozzle height
  • Clean print platform
  • Add Glue
  • Textured sheets for cold platforms

Back to overview

3D Printing Problems #4: Layer Misalignment

3D Printing Problems: Layer Misalignment

What’s the 3D Printing Problem?

Some layers in the middle of the objects have shifted.

What’s Causing this 3D Printing Problem?

The printer belts aren’t well tightened. The top plate isn’t fastened and wobbles around independent of the bottom plate. One of the rods in the Z axis is not perfectly straight.

3D Printer Troubleshooting: Layer Misalignment

  1. Check the belts. Start by checking each of the belts are tight but not over tight. You should feel a little resistance from the two belts as you pinch them together. If you find that the top section of the belt is tighter than the bottom then this is a sure fire sign that they need a tweak and tighten.
  2. Check the top plate. Check the top plate and all rods and attachments at the top of the printer and make sure everything is tight and aligned.
  3. Check the Z axis rods. Many printers use threaded rods rather than lead screws and although these do the job they do have a tendency to bend over time. Don’t worry about dismantling your printer to see if they’re straight, simply use the software such as ‘Printrun’ to move the print head up or down. If one of the Z axis rods is bent you’ll instantly see. Unfortunately, it’s almost impossible to accurately straighten a rod once it’s bent, but on the upside, it’s a good excuse to replace the old threaded rods for lead screws.

3D Printing Problem Checklist: Layer Misalignment

  • Check the tension in the belts
  • Check there’s no movement in the top plate
  • Make sure the Z axis rods are straight

Back to overview

3D Printing Problems #5: Missing Layers

3D Printing Problems: Missing Layers

What’s the 3D Printing Problem?

There are gaps in the model because some layers have been skipped (in part or completely).

What’s Causing this 3D Printing Problem?

The printer failed to provide the amount of plastic required for printing the skipped layers. This is called (temporary) under-extrusion. There may have been a problem with the filament (e.g. the diameter varies), the filament spool, the feeder wheel or a clogged nozzle.

Friction has caused the bed to temporarily get stuck. The cause may be that the vertical rods are not perfectly aligned with the linear bearings.

There is a problem with one of the Z axis rods or bearings. The rod could be distorted, dirty or had been oiled excessively.

3D Printer Troubleshooting: Missing Layers

  1. Mechanical check. It’s good practice to give your 3D Printer the once over every now and again and the appearance of gaps in your 3D print are always a good sign that now is the time to give your 3D printer some love and attention. Start off by checking the rods and make sure that they’re all seated into either bearings or clips and haven’t popped out, shifted or moved even slightly.
  2. Rod alignment Check. Make sure that all rods are still in perfect alignment and haven’t shifted. You can often tell by switching off the power (or disabling steppers) and then gently moving the print head through the X and Y axis. If there is any resistance to the movement then something is wrong and it’s usually pretty easy to tell if this is due to misalignment, a slightly bent rod or one the bearings.
  3. Worn bearing. When bearings go they usually let you know about it by creating an audible din. You should also be able to feel uneven motion in the print head and when printing the machine looks like it’s vibrating slightly. If this is the case unplug the power and move the print head through the X and Y to locate the region of the broken bearing.
  4. Check for oil. Lubricating the joints is easy to forget, but keeping everything well oiled is essential to the smooth running of the machine. Sewing machine oil is ideal and can be purchased for almost any haberdashery at a relatively inexpensively price. Before you go applying liberally just check that the rods are clean and free of dirt and printing debris, a quick wipe of the rods before applying fresh coat of oil is always a good idea. When all rods look clean just dab on a little, but not too much. Then use print such as Printrun to move the head through the X and Y axis to make sure that the rods are evenly covered and moving smoothly. If you add a little too much oil don’t worry just wipe some off with a lint free cloth.
  5. Under-Extrusion. The final issue could be under-extrusion and finding the solution for this can cumbersome. See 3D Printing Problems #9: Under-Extrusion.

3D Printing Problem Checklist: Missing Layers

  • Check over the mechanics and make sure everything is tight.
  • Double check the printer’s construction and alignment
  • Listen out for worn bearings and bent rods
  • Add a little oil to keep things running smooth

Back to overview

3D Printing Problems #6: Cracks In Tall Objects

3D Printing Problems: Cracks In Tall Objects

What’s the 3D Printing Problem?

There are cracks on the sides, especially on taller models. This can be one of the most surprising issues in 3D Printing as it tends to manifest itself in larger prints, and usually whilst you’re not looking.

What’s Causing this 3D Printing Problem?

In higher layers, the material cools faster, because the heat from the heated print bed doesn’t reach that high. Because of this, adhesion in the upper layers is lower.

3D Printer Troubleshooting: Cracks In Tall Objects

  1. Extruder temperature. Start by increasing the extruder temperature; a good start would be to increase it by 10ºC. On the side of your filament box you’ll see the working hot end temperatures, try to keep the temperature adjustment within these values.
  2. Fan direction and speed. Double check your fans, make sure that they’re on and aimed at the model. If they are try reducing their speed.

3D Printing Problem Checklist: Cracks In Tall Objects

  • Check the hot end temperature and raise at 10-degree intervals
  • Check the position and speed of the cooling fans

Back to overview

3D Printing Problems #7: Pillowing

3D Printing Problems: Pillowing

What’s the 3D Printing Problem?

The top surface of the print shows unsightly bumps or even holes.

What’s Causing this 3D Printing Problem?

The two most common causes are improper cooling of the top layer and that the top surface isn’t thick enough.

3D Printer Troubleshooting: Pillowing

  1. Filament size. More common with 1.75 mm filament. Pillowing is an issue that can affect all 3D printers, however, it’s far more common on those using 1.75 mm filament over 2.85mm.
  2. Check the fan position. Cooling is normally the issue start by checking your fans. As the print starts your printers fans will be set to low or off, after the first few layers have printed they should kick into action. Check that the fans around the hotend start to spin, then as the print finishes check the fans are all good and working. If all seems OK just double check that the direction of the fans is correct and that they’re pushing cool air towards your print and not elsewhere.
  3. Set fan speed in G-Code. Another cooling issue happens when each successive top layer of molten plastic is applied. As it covers the inner support structure it needs to be cooled quickly to avoid falling into the holes between the supports. The speed of the fans can be adjusted in the G-Code, a common G-Code for Fan On is M106 and is M107 Fan Off. You then just need to the Fan speed to maximum for those top layers.
    An example would for a 1cm x 1cm cube printer at 0.1mm layer height. The G-Code in this case output through CURA for the Prusa i3, we can look through the code and see that there are 97 layers. Knowing that we have a ‘Bottom / Top Thickness setting’ of 0.6mm we can look back to ;LAYER:91 then in the line after add M106 S255. M106 sets the fan going and S255 sets it to full blast.
  4. Increase top layer thickness. The easiest solution is to increase the top layer thickness. Most applications will enable you to do this in the advanced section, under the ‘Bottom / Top Thickness setting’. You’re aiming for at least 6 layers of material normally and up to 8 for smaller nozzles and filament. If your layer height is therefore set to 0.1mm then set the ‘Bottom / Top Thickness setting’ to 0.6mm. If the effect of pillowing still exists then increase to 0.8mm.

3D Printing Problem Checklist: Pillowing

  • Go large and increase the filament size
  • Make sure the fans are up to speed and positioned
  • Manually set the fan speed
  • Increase the top layer thickness

Back to overview

3D Printing Problems #8: Stringing

3D Printing Problems: Stringing

What’s the 3D Printing Problem?

There are unsightly strings of plastic between parts of the model.

What’s Causing this 3D Printing Problem?

When the print head moves over an open area (otherwise known as travel move), some filament has dripped from the nozzle.

3D Printer Troubleshooting: Stringing

  1. Enable Retraction. Retraction is an important factor when it comes to quality of finish and can be enabled through most slicing software. Its function is pretty simple and works by retracting the filament back into the nozzle before the head moves. The idea is that it avoids molten filament from trailing behind the head creating thin strings in its wake.
  2. One click retraction activation. Most applications such as Cura offer a one click activation option, this uses a set of default parameters and for the most part is perfectly adequate. However, if you want a few more options there’s often a more settings buttons. Here you can adjust the minimum travel of the head before retraction is activated.
  3. Minimum travel (mm). Reducing the minimum travel is usually the quickest fix for stringing if the standard retraction isn’t doing the job. Drop the value in 0.5mm until stringing is stopped. Activating retraction will increase your print speeds.
  4. Just cut them off. This isn’t the most elegant of solutions but simply taking a scalpel to the strings is quite often the quickest and easiest solution, and has the benefit that it doesn’t increase print times.

3D Printing Problem Checklist: Stringing

  • Enable retraction
  • Adjust the minimum travel before retracting starts
  • Just clean the print with a scalpel

Back to overview

3D Printing Problems #9: Under-Extrusion

3D Printing Problems: Under-Extrusion

What’s the 3D Printing Problem?

Under-extrusion is when the printer cannot supply the material needed (or as fast as needed). Under-extrusion results in thin layers, in layers with unwanted gaps, or in missing layers entirely (see 3D Printing Problems #5: Missing Layers).

What’s Causing this 3D Printing Problem?

There are several possible causes. First, the diameter of the filament used does not match the diameter set in the slicing software. Secondly, the amount of material that is extruded is too low because of faulty slicer software settings. Alternatively, the flow of the material through the extruder is restricted by dirt in the nozzle.

3D Printer Troubleshooting: Under-Extrusion

  1. Check the filament diameter. Start with the simplest issue, have you set the correct filament diameter in the slicing software. If you’re unsure about the diameter the value along with the recommended temperature is usually printed on the box.
  2. Measure the filament. If you’re still not getting the results you want and filament flow is the issue, then use a set of calipers to double check the filament diameter. You should be able to tweak the filament diameter settings accurately in the slicer software settings.
  3. Check the head. After printing, most printers will lift the printhead away from the print base. Quickly check that the nozzle is clear from a build up of filament and dirt.
  4. Set the extrusion multiplier. If there is no mismatch between actual filament diameter and the software setting, then check the extrusion multiplier (or flow rate or flow compensation) setting may be too low. Each slicer application will handle this slightly differently but the principle is to increase the setting in steps of 5% and then restart the print process.
    In Simplify3D open the Edit Process Settings dialog and go to the Extruder tab – the Extrusion multiplier setting of 1.0 corresponds to 100%; In Cura open the Material tab and increase the Flow setting (you may need to enable the Flow setting through the Preferences dialog).

3D Printing Problem Checklist: Under-Extrusion

  • Check the filament diameter
  • Use calipers to measure the filament diameter
  • Check that the hot end is clear
  • Adjust the extrusion multiplier at 5% intervals

Back to overview

3D Printing Problems #10: Over-Extrusion

3D Printing Problems: Over-Extrusion

What’s the 3D Printing Problem?

Over-extrusion means that the printer supplies more material than needed. This results in excess material on the outside of the model printed.

What’s Causing this 3D Printing Problem?

Typically, the Extrusion multiplier or Flow setting in your slicing software is too high (see the section above)

3D Printer Troubleshooting: Over-Extrusion

  1. Extrusion multiplier. Open your slicer software and check that you have the correct Extrusion multiplier selected.
  2. Flow setting. If that all looks correct then decrease the Flow setting in your printer’s software.

3D Printing Problem Checklist: Over-Extrusion

  • Check you have the right extrusion multiplier settings
  • Decrease the filament flow settings

Back to overview

3D Printing Problems #11: Shifting Layers

3d printing problems

What’s the 3D Printing Problem?

The lower and top layers shift so that you get a stepping effect through the print. Usually it’s quite subtle, but these images shows a print with a more pronounced effect.

What’s Causing the 3D Printing Problem?

There’s a variety of reasons for shifting layers, and these can be as simple as someone knocking the printer during the print process! More involved shifting layer problems can be down to bent or misaligned rods, or even the nozzle catching on the print and causing a slight shift in position of the platform.

3D Printer Troubleshooting: Shifting Layers

  1. Check that the printer is on a stable base. Place the printer on a stable base and in a location where it will avoid being knocked, pocked and generally fiddled with. Even a small nudge of the printer can shift the print base and cause issues.
  2. Check the print base is secure. Most 3D printers use some form of detachable print base. Although this is handy when it comes to removing prints, and of course avoids damage to the printer, it also means that over time clips and screws can work loose. Make sure that when you reinstall the print platform it’s clipped or bolted tightly in place to avoid any slip or movement.
  3. Watch out for warped upper layers. If you’re printing a high quality print upper layers can easily warp if cooled too quickly. As the layers warp they rise and can cause an obstruction to the nozzle as it moves, in most cases the print will release from the platform, but if it doesn’t the powerful stepper motors can push the print and platform around.  If your prints are suffering from warping in the upper layers try reducing the speed of the fans slightly.
  4. Printing too fast for your machine. It is possible to speed up the print times for your machine by increasing temperature and flow. However whilst this may result in the filament flowing in the correct quality the rest of the machine may struggle to keep up. If you hear a clicking during printing this could  be a sign that the printer is going to fast. If you do hear a click the first port of call is to check that the filament isn’t slipping, before you take a look at the actual printer speed. To adjust your printers speed open up your slicer software and change the print speed.
    In Simply 3D go to ‘Other > Default Printing Speed (mm/min)’
    In Cura go to ‘Basic > Print Speed (mm/s)’
  5. Check the belts. If layers are still shifting then it’s time to check the belts. A quick check is to just go around all belts and pinch the two together. The tension in each belt should be the same, if not then you’ll need to adjust the belt position to even out the belt tension. Over time the rubber belts will stretch (You can often tell if they do as they’ll start to slip on the drive pulleys), if there is quite a bit of play in the belts then it’s time to replace them with new ones. Over tight belts can also be an issue but this is usually only a problem if you’ve built the machine yourself. Some printers such as the Prusa i3 have belt tensioning screws that enable you to easily adjust the belt tensions.
  6. Check the drive pulleys. These are the usually connected directly to a stepper motor or to one of the main rods that drives the print head. If you carefully rotate the pulley you’ll see a small grub screw. Hold onto the rod and taking hold of the attached belt and then tug the belt and try to force the pulley to turn. You should find that there is no slip between the pulley and stepper or rod, if there is tighten the grub screw and try again.
  7. Check the rods are clean and give them some oil. Over time debris can build up on the rods which means that at some points along their length they cause more friction than others, which in turn can affect the free movement of the head and again cause layer shifting. A quick wipe and re-oil of the rods usually solves the issue.
  8. Bent or misaligned rods. If you see the print head falter at certain points then it could be that one of the rods has become slightly bent. You can usually tell by switching off the machine so there’s no power going through the steppers and then move the print head through the X and Y axis. If you feel resistance then you know something is amiss. Start by seeing if the rods are aligned, if they are then remove the rods and roll them on a flat surface. If any are bent then it will be quite obvious.

3D Printing Problem Checklist: Shifting Layers

  • Check that the printer is on a stable base.
  • Check the print base is secure.
  • Watch out for warped upper layers.
  • Printing too fast for your machine.
  • Check the belts.
  • Check the drive pulleys.
  • Check the rods are clean and give them some oil.
  • Bent or misaligned rods.

Back to overview

3D Printing Problems #12: Blocked Bowden Nozzle

3D Printing Problems Blocked nozzle

What’s the 3D Printing Problem?

You initiate a print job but whatever you try, nothing comes out of the nozzle. Extracting the filament and reinserting doesn’t work.

What’s Causing the 3D Printing Problem?

A small piece of filament has been left behind in the nozzle after changing spools, often because the filament has snapped off at the end. When the new filament is loaded, the piece of old filament that is left in the nozzle doesn’t allow the new filament to be pushed through.

Alternatively, a build up of molten plastic in the end of the nozzle has hardened and will need manual removal. Specialist, cheap or old filaments are a common cause.

3D Printer Troubleshooting: Blocked Bowden Nozzle

  1. Unblock with a needle. If you’re lucky then unblocking can be a quick and easy process. Start by removing the filament. Then using the control panel select the “heat up nozzle” setting and increase to the melting point of the stuck filament. In the case of the Ultimaker 2 go to Maintenance > Heat Up nozzle. For PLA set the temperature to 220 C. Once the nozzle reaches the correct temperature, use a small pin to clear the hole (being careful not to burn your fingers). If your nozzle is 0.4mm then you need a pin that is smaller; an airbrush cleaning kit works perfectly. It’s also worth getting a brass cleaning brush to remove any filament build-up on and around the nozzle.
  2. Push old filament through. If you find that the nozzle is still blocked then you may be able to push the filament through with another bit of filament. Start by removing the filament as before and then remove the feeder tube from the print head. Heat up the hot end to 220 C for PLA and then using another piece of filament push this through from the top to try to force the stuck filament in the nozzle out. Usually if new filament hasn’t succeeded in unblocking then the extra pressure you can exert by hand might just do the job. However don’t push to hard as you’ll bend the horizontal printer rods.
    Once the end clears use a needle to push through the nozzle and a brush to clean any filament excess.
  3. Dismantle and rebuild the hotend. In extreme cases when the nozzle remains blocked, you’ll need to do a little surgery and dismantle the hot end. If you’ve never done this before then it’s a good idea to make notes and take photographs so you know where everything fits when you reassemble. Start by removing the filament, then check your printer’s manual to see exactly how to dismantle the hot end.

In the case of the Ultimaker 2, it’s all quite straightforward. At all times during this procedure be aware that the hot end will get hot so a pair of heat proof gloves is advised (e.g. welder’s gloves).

For the Ultimaker 2 move the print head to the centre of the printer. Undo the four screws on top of the print head and let the hot end and fans hang down.
Increase the temperature of the hot end to 220 C (For PLA) and wait for the hot end to reach temperature. Once the printer reaches the correct temperature switch off the power.

Holding onto the plastic fan housing use a pair of tweezers through the top of the nozzle to grab hold of the offending filament and extract.

Use a needle to push all the way through and then a brass cleaning brush to remove any excess filament.

Switch the printer off and leave to cool.

Once completely cool reassemble, switch on and load a new spool of filament.

3D Printing Problem Checklist: Blocked Bowden Nozzle

  • Heat the nozzle and clean with a needle and brass cleaning brush.
  • Remove the feeder tube and try pushing the filament through with another piece of filament.
  • Dismantle the hot end and see if you can extract the filament blockage.

3D Printing Problems #13: Snapped filament

3d printing problems

What’s the 3D Printing Problem?

The filament spool still looks full, and when you check there appears to be filament in the feed tube, but nothing’s coming out of the nozzle. This is more of an issue with Bowden feed printers than direct feed as the filament is hidden so breakages aren’t always immediately obvious.

What’s Causing the 3D Printing Problem?

Caused by a number of issues but primarily old or cheap filament. Although the majority of filaments such as PLA and ABS do last a long time, if they’re kept in the wrong conditions such as in direct sun light then they can become brittle. Then once fed into the printer no amount of adjustment is going to help.

Another issue is filament diameter, and this can vary through manufacturer and batch. Sometimes if the idler tensioner is too tight then some filament that still has a good amount of life left in it can snap under the pressure.

3D Printer Troubleshooting: Snapped Filament

  1. Remove the filament. The first thing to do is to remove the filament from the printer in the usual way. In the case of the Ultimaker select Maintenance and Change Material. As the filament will usually have snapped inside the tube you’ll need to remove the tube from both the extruder and hotend. Then heat the nozzle and pull out the filament.
  2. Try another filament. If after reloading the filament it happens again, use another filament to check to see if it’s not just the old brittle filament that should be disposed off.
  3. Loosen the idler tension. If the new filament snaps check that the idler tensioner isn’t too tight by loosening all the way. As the print starts tighten until there is no slippage of the filament.
  4. Check the nozzle. Check the nozzle isn’t blocked and give it a good clean.
  5. Check flow rate and temperature. If the problem continues check that the hotend is getting hot and to the correct temperature. Also check that the flow rate of the filament is at 100% and not higher.

3D Printing Problem Checklist: Snapped Filament

  • Check the filament isn’t past its best
  • Check the filament diameter
  • Adjust the idler tension
  • Check that the hot end is clear and reaches the correct temperature
  • Set the flow rate to 100%

3D Printing Problems #14: Stripped filament

3D Print Problems - Stripped filament

What’s the 3D Printing Problem?

Stripped or slipping filament can happen at any point of the print process, and with any filament. The result is that no filament is extruded from the hot end bringing your print to an abrupt end.

What’s Causing the 3D Printing Problem?

Blockage, loose idler tensioner, wrong hot end temperature, these are just a few of the common causes, but all are usually easy to correct. The result of the problem is that the knurled nut or toothed gear in the extruder is unable to pull or push the filament through the printer. As the motor spins the small teeth on the gear that would usually grip and feed the filament through the system, instead wear it away until there is no longer any grip, and the gear and filament slip.

3D Printer Troubleshooting: Stripped Filament

  1. Help feed the system. If the filament has just started to slip, you can usually tell by the noise and the appearance of plastic shavings, then apply some gentle pressure to the filament to help it through the system. This will often help to get the machine printing smoothly again.
  2. Adjust the Idler tension. Start by loosing the idler, feed in the filament and tighten until it stops slipping. Filaments vary in diameter so although the idler will absorb some difference in diameter some filaments will require fine adjustment.
  3. Remove the filament. In most cases you’ll need to remove and replace the filament and then feed it back through the system. Once the filament has been removed cut the filament below the area that shows signs of slipping and then feed back into the system. If the filament has snapped it may be passed its usable best. Try it again and if it snaps again and you find the filament appears brittle discard and use another filament.
  4. Check the Hot end temperature. If you have just inserted a new filament as the issue started, double check that you have the right temperature.

3D Printing Problem Checklist: Stripped Filament

  • Help feed the system
  • Adjust the idler tension
  • Remove the filament
  • Check the hot end temperature