Troubleshooting Guide to 24 Common 3D Printing Problems| Part 1

3D printing trouble shooting guide

Fused Filament Fabrication Frustrations? Read our 3D printing troubleshooting guide to 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 make 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 24 of the most common 3D printing problems 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 #1: Blocked Bowden 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 Printing 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.

3D Printing Problem Checklist: Blocked Bowden Nozzle

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

3D Printing Problems #2: Broken Infill

What’s the 3D Printing Problem?

The internal structure of your print is missing or broken.

What’s Causing this 3D Printing Problem?

There are a number of reasons for the misprinting of the internal structure. The most common is incorrect settings within the slicing software, but it can also be due to a slightly blocked nozzle.

3D Printing Troubleshooting: Broken Infill

  1. Check the Fill density. In your slicing software check the infill density. A value of around 20% is normal; any less than this and you’re likely to have issues. For larger prints you may want to increase this to ensure that the model has enough support.
  2. Infill Speed. The speed at which the infill is printed can have a major effect on the quality of the structure. If the infill is looking week then decrease the infill print speed.
  3. Change the pattern. Most slicing software enables you to change the internal structure. You can have a grid pattern, or triangle, honeycomb, and more. Try selecting a different option.
  4. Check your nozzle. It might be that there is a slight blockage in the nozzle. While the blockage doesn’t effect the printing of the thicker exterior walls, because there is less flow for the internal structure the filament is getting caught.

3D Printing Problem Checklist: Broken Infill

  1. Check and adjust the Fill density
  2. Decrease the Infill Speed
  3. Try a different infill pattern
  4. Check your nozzle for blockages

3D Printing Problems #3: 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 Printing 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

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

3D Printing Problems #4: 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 Printing 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

  1. Balance print platform temperature and fan speed
  2. Level the print platform
  3. Check the nozzle height
  4. Chamfer the model base

3D Printing Problems #5: Extrusion Temperature Too High

What’s the 3D Printing Problem?

Filament is surprisingly resilient to all types of misconfiguration, including overheating of the hot end. It’s for this reason of resilience that noticing your hot end is too hot isn’t always as easy as you’d think it would be. The effects can be as obvious as discolored filament; in our sample here the dark line that appears half way up 3D Benchy is an obvious sign of scorching where the filament has burnt. This scorching can just appear as slight discoloration or darkening which is less obvious than the dark line above.

Another sign can be the appearance of uneven layers; when you take a closer look you can see that it’s not so much uneven as melted. Again our model shows this subtly on the cabin, and to a far greater effect on the chimney where it starts to look a little like wax running down a melted candle.

Overheating filament can also cause huge issues with accuracy especially when it comes to threadscrew holes. Finding that some holes are correct and others are too small is often an initial sign that the temperature may well be a little too high.

What’s Causing this 3D Printing Problem?

Normally, having too hot a hot end or overheating is an easy fix. The hot end is too hot so you need to cool it down. There needs to be a fine balance between melting the filament so that it will flow, and enabling the filament to solidify quickly so that the next layer can be applied to a solid surface. Before you go adjusting the temperature however, first make sure that you have loaded the correct material settings for your 3D printer (as part of the filament loading process). If you have, then it could be that you need to adjust the temperature just a touch.

3D Printing Troubleshooting: Extruder Temperature Too High

  1. Check the material settings. This might seem obvious, but just double check that you’ve given the printer the correct details about the material. The latest filament temperatures range from between 180 – 260ºC or thereabout, so it’s surprising how easy it is to get this wrong.
  2. Decrease the hot end temperature. In the printer or software settings decrease the hot end temperature. Depending on the severity of the overheating, drop the temperature in 5ºC intervals.
  3. Speed up the print. If the filament isn’t being discoloured then you could try speeding up the print speed.
  4. Check the fans. Check that the cooling fans are directed at the hot end. Check that they’re in the right position and if possible boost their speed to increase airflow over the cooling filament.

3D Printing Problem Checklist: Extruder Temperature Too High

  1. Check the material settings.
  2. Decrease the hot end temperature.
  3. Speed up the print.
  4. Check the fan position.

3D Printing Problems #6: Gaps between Infill and Outer Wall

What’s the 3D Printing Problem?

When you look at the top or bottom of the print, you can see a slight gap between the infill and the outer perimeter walls.

What’s Causing this 3D Printing Problem?

Gaps between the perimeter and top layers used to be a common problem, but as printer accuracy has improved and the support for different materials extends, it’s now less of an issue than it was.

However the new wave of advanced materials are far less forgiving than the likes of PLA and ABS, and we’re starting to see a slight resurgence of the problem.
Gaps are caused by the filament used for the infill and outer walls not quite meeting bonding and is a relatively easy fix.

The most obvious cause of the problem is that the infill overlap is not set, or it’s set to “0”. This means that the slicing software is actually telling the printer not to allow the two parts of the print to meet.

Another issue could be the order in which you have set the infill and outer perimeters to be printed. If you’re printing the perimeter first for a high-quality print then there is generally little or no overlap which can again cause the problem.

3D Printing Troubleshooting: Gaps between Infill and Outer Wall

  1. Check the infill overlap. This is by far the most common issue and is really easy to resolve. In your slicing software locate the ‘Infill Overlap’ option and increase the value.
    • In Cura by default this is set to 15% so raise it to 30%.
    • In Simplify3D you’ll find the option in ‘Edit Process Settings > Infill > Outline Overlap’ again increase the value. This setting is directly linked to the extrusion width, so the % value will be a % of whatever you’re extrusion width is. When adjusting this setting always keep it below 50% or you’ll start to see the effects of the overlap in the outer perimeters of your print.
  2. Printing infill before the perimeter. If you’re printing with a relatively thin outer wall the structure of the infill can show through. If this happens then you can switch the order by which the printer lays down the infill and perimeter layers. For example, in Cura check to see if you have ‘Infill prints after perimeters’ ticked.
  3. Increase Hot end temperature. Some of the latest advanced materials such as XT-CF20 are a little less forgiving when it comes to spread due to the carbon fibres that make up part of their structure. When printing with these materials you may find that a slight 5-10º increase in hotend temperature makes all the difference.
  4. Slow it down. Okay, so you may be in a rush to get the printout, but printing at higher speeds can cause all sorts of issues if the printer isn’t perfectly calibrated. If you need to print quick you can still avoid gaps by decreasing the speed of the top layer.

3D Printing Problem Checklist: Gaps between Infill and Outer Wall

  1. Check the infill overlap.
  2. Printing infill before the perimeter.
  3. Increase Hot end temperature.
  4. Slow it down.

3D Printing Problems #7: Ghosting of the Internal Structure

What’s the 3D Printing Problem?

The final print looks fine but an outline of the internal support structure can be seen through the walls of the print.

What’s Causing this 3D Printing Problem?

The issue with ghosting happens due to the infill encroaching into the path of the perimeter. This effect is most visible when your print has thin walls. The problems is caused by the infill structure overlapping with the perimeter line as it’s being laid down. Although this ghosting is an issue it’s actually an important part of the printing process, as it helps the internal structure bond effectively to the external walls. Luckily it’s very easy to overcome.

Another cause of ghosting can be that you have set an incorrect wall thickness in relation to the size of nozzle that you’re using. In normal print conditions the size of the nozzle should be directly related to the nozzle size, so if you have a 0.4mm nozzle then the wall thickness should be a multiple of this, either 0.4, 0.8, 0.12 and so forth.

3D Printing Troubleshooting: Ghosting of the Internal Structure

  1. Check the shell thickness. Make sure that the value you have selected for the shell thickness is a multiple of the nozzle size.
  2. Increase the shell thickness. The easiest solution is to increase the shell thickness. By doubling the size it should cover any overlap caused by the infill.
  3. Use Infill after perimeters. Most slicing software will enable you to activate Infill prints after perimeters.
    • In Cura open up the ‘Expert Settings’ and under the Infill section tick the box next to ‘Infill prints after perimeters’
    • In Simply3D Click ‘Edit Process Settings’ then select ‘Layer’ and under ‘Layer Settings’ select ‘Outside-in’ next to the ‘Outline Direction’.
  4. Check print platform. Check around the model and if you see that the effect is more prevalent on one side than the other, the effect could be due to calibration. If so run through the usual calibration process.
  5. Use it to your advantage. Depending on the type of model that you’re printing you can use the internal and shell printing order to your advantage. When you want a high-quality print with a good surface finish where the actual strength of the model isn’t important, select print from the Outside-in. If however the strength of the print is paramount then select Print from in Inside-Out and double the wall thickness. The reason for the difference in strength is that when you print from the Outside-in you eliminate the small amount of overlap that causes the ghosting issue, but this also means that the actual structure won’t create the same strength of bond between the internal and external structure due to the lack of overlap.

3D Printing Problem Checklist: Ghosting of the Internal Structure

  1. Check the shell thickness.
  2. Increase the wall thickness.
  3. Use Infill after perimeters.
  4. Check print platform and recalibrate if necessary.
  5. Use it to your advantage.

3D Printing Problems #8: 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 Printing 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

  1. Check the tension in the belts
  2. Check there’s no movement in the top plate
  3. Make sure the Z axis rods are straight

Via all3dp.