5 common 3D printing problems and how to fix them

5 common 3D printing problems and how to fix them

Owning a 3D printer is a love/hate relationship. You have the power to prototype and create almost anything you can imagine from something as simple as a pencil holder to an entire Iron Man suit. But sometimes your printer just doesn’t want to cooperate. As 3D printer owners ourselves, we know your frustration. That’s why we’ve listened to your feedback to create a list of the top 5 common 3D printing problems and how to fix them.

The most requested 3D printing troubleshooting issues we received were stringing, over and under extrusion, overhangs, prints not sticking to the print bed and bed leveling. Like most 3D printer issues, addressing and correcting them is equal parts your printer and your slicing software. We highly recommend you check your respective printer’s manual, as well as, any instructions, tutorials or user guides for any software you use before troubleshooting.

Stringy Filament

Example of stringy filament on a 3D print

Have you ever printed an object that looks like it is growing filament hair? This is known as stringing. Stringing most commonly occurs when your printing project has spaces or gaps between parts.

Stringy Filament Solution

The most common solution is retraction. Programs like CuraEngine and Slic3r have a preconfigured retraction setting. Sometimes the presets aren’t as accurate as they should be. Adjust the retraction speed and try it on a few test prints to see what works best for your printer.

Another option is your extruder temperature. Having a temperature that is too high can cause filament to lose its viscosity and print out stringy. For printing with PLA on Velleman 3D printers, we recommend setting the temperature between 190°C to 210°C. Depending on the brand, material and diameter of your filament, your extruder temperature may vary. Adjust in 5 to 10-degree increments to find the perfect temperature for your filament. It is also a good idea to examine the room your 3D printer is stationed. Things like humidity, altitude and room temperature can also result in stringy filament.

Over and Under Extrusion

Example of under extrusion on a 3D print

A common issue with beginners and experts alike is filament extrusion. Over extrusion occurs when your 3D printer extrudes more filament than expected. It causes globs of filament and uneven, messy prints that aren’t easy on the eyes. Under extrusion occurs when there isn’t enough filament during printing, which leaves gaps between layers.

Over Extrusion Solution

The most common solution to over extrusion is filament diameter. Ensure that the 3D printer accepts the diameter of your filament. For example, the Velleman K8200 prints with 3 mm filament before the K8203 upgrade. If you were to try and print with our 1.75 mm filament, over extrusion would occur. Your slicing software and 3D printer software may also be the issue. It is imperative that you match the correct filament diameter with not only the diameter that is recommended for your printer but also with slicing and 3D printer software.

Under Extrusion Solution

While reversing the over extrusion troubleshooting for filament diameter can also remedy under extrusion, we found that most people experience under extrusion due to flow rate or the extrusion multiplier of your 3D printing software. For example, if your multiplier was moved from 1 to 0.8, try increasing it up to 0.9 to see if it resolves under extrusion.


Example of overhanging filament on a 3D print

Overhangs are parts of your print where upper layers extend horizontally past the layers below them. As filament extrudes and brings your print to life, the print speed and angles can cause overhanging layers to fall apart or droop.

Overhang Solution

First things first, take a look at your print speed. We all want our prints to complete as fast as possible but throttling your print speed is not the answer. Set appropriate print times according to your printer’s user manual.

Next, take a look at your print. Are you trying to print overhang angles that defy the laws of gravity? If so, your print is destined to fail. Try adjusting the print’s angles to something more reasonable, building a more durable print base or slowly increasing the print’s angles instead of rushing straight to that 70° bridge you’re trying to build. Alternatively, you could also break your print into separate prints to get the desired results.

Lastly, take a look at the temperature and fans on your printer. Temporarily lowering the extruder temperature a few degrees and/or increasing your cooling fans can give your top layers time to cool and stop overhanging.

Bed Leveling

Example of bed leveling on a 3D printer

Most 3D printers require manual bed leveling before printing. If you’ve just assembled your printer or recently moved it to a different location, your printer is most likely in need of bed leveling.

Bed Leveling Solution

If your printer has manual bed leveling settings such as our K8200, it is highly recommended you follow the user manual to level your print platform. Additionally, your printing software should have an automatic bed leveling function to assist you.

Prints Not Sticking to Bed

The first layer is the most important in any 3D print. If your first layer is not 100% in place, your print job will not turn out as great as it looks in your 3D modeling software.

Prints Not Sticking to Bed Solution

Ideally, you should already check to see if your bed is level. Uneven bed equals uneven first layer. Next, check your Z axis offset to see where your nozzle is compared to the print bed. If it is too far away, your printer is printing on air and will not extruder accurately. If it is too close, you face damaging your print bed and nozzle.

Finally, take a look at your print bed surface. Heat beds like the K8200 require certain temperature settings depending on the filament. Print surfaces that use a film or tape similar to the K8400, K8600 and K8800’s BuildTak surface may require a sheet replacement.


If you’ve tried everything in our guide and are still having trouble with your Velleman printer, don’t worry! You’re more than welcome to reach out to us directly or on our forum.

Let us know if you have any additional 3D printing solutions you’d like to share! Comment below or tweet us @VellemanStore.