7 Common 3D Printing Problems With Solutions     

3D printing problems with solutions

3D printers can produce amazing things, but they can also produce incredible disasters.

Whether over extrusion or blobs on the print surface, you can face various issues when 3D printing. The good news is that most 3D printing problems have simple fixes, and you don’t need to go back to school or buy a new printer.

This article runs through seven common 3D printing problems with solutions to help you get a handle on your 3D printing.

Let’s jump in!

1. Under and over extrusion

Under extrusion problem

Under extrusion happens when the 3D printer doesn’t extrude enough plastic, leaving gaps between the perimeter and infill.

When the nozzle doesn’t extrude enough plastic, you will notice gaps between the adjacent extrusions of each layer. This impacts the print quality and compromises the structural integrity of parts, leading to mechanical failures.

Over-extrusion happens when a printer prints too much plastic, causing a build-up of excess plastic that makes parts look like they are melting.

The cause

The most common cause of under and over-extrusion is an incorrect extrusion multiplier – a setting in the software that specifies the rate at which your printer will extrude material.

Another common cause of under and over-extrusion is incorrect filament diameter, which affects the flow rate and interlayer adhesion.

The solution

You can solve under, and over-extrusion problems by adjusting the multiplier up or down in software and making sure the filaments you use are the correct diameter.

2. Stringing (hairy prints)

3D print stringing problem

Stringing is a common issue when printing at high temperatures, and it occurs when small strings of plastic are left behind by the nozzle, leaving traces. Plastic oozing from the nozzle also wastes material and increases print costs.

Stringing is most common when printing smaller parts and models, which decreases travel between the nozzle and the following location.

The cause

The most common cause is incorrect retraction settings. Retraction distance (how much plastic is pulled out of the nozzle) and retraction speed (how fast plastic is retracted from the nozzle) are common problems.

It could also be that the extruder temperature is too high – this liquefies the thermoplastic, causing excessive oozing.

The solution

Check the retraction settings on your 3D printer. Configure the retraction distance and retraction speed for the material you are printing. You can increase/decrease the retraction distance by 1mm to see improvements.

If the extruder temperature is too high, turn it down, even if it means going against what the material manufacturer says – your 3D printer might run hotter than it says. Experiment to find the best print settings.

You can also try different filaments to eliminate stringing. PLA is prone to oozing and stringing, while ABS is less prone to these issues.

3. Layer separation and splitting

3D printing problem - layers seperating

When layers separate, they split apart during printing, destroying the session. Each successive layer needs printing with perfect inter-layer adhesion. Otherwise, parts can split and warp, creating lots of material waste.

The cause

The common cause of layer separation is excessive layer heights, where plastic is pushed through in too large a volume. You want the layer height to be around 20% smaller than the nozzle diameter so that layers bond correctly.

Another cause of layer separation is low print temperatures, inhibiting thermoplastic chemical bonding processes. It’s easy to get caught when switching or trying filaments from new manufacturers.

The solution

Refine your layer height for the nozzle. We recommend a layer height 20% smaller than your nozzle diameter (e.g., a 0.32mm layer height for a 40mm nozzle). Try reducing the layer height and see if it helps.

If you print at too low a temperature, crank it up a little. Increments of 3°C are safe to try with most rigid thermoplastics.

Another top tip is regulating the temperature of your print environment. If your printer has a heated chamber, try heating it by 5°C.

4. Blobs and zits on the surface 

Blobs and zits 3D printing

3D prints are primarily judged by their surface quality, with blobs and zits hallmarks of either a low-quality 3D printer or an amateur maker. But don’t be disheartened – blobs affect everyone because they depend on settings.

Blobs and zits are common after turning a printer on and off due to variations affecting the extruder system.

The causes

Retraction and coasting settings can cause blobs and zits. If imperfections appear the moment the perimeter is printed, your retraction settings need adjusting to account for the distance between when the extruder stops and starts.

If your printer has a Bowden extruder, it’s helpful to avoid retractions so that it doesn’t have to reverse, although this can cause stringing (see above).

The solution

Adjusting retraction settings allows you to avoid minor surface defects like blobs and zits. If the defect occurs when the extruder comes to a stop, the coasting setting is helpful to switch off the extruder a little before it reaches the perimeter. Coasting sets the speed the nozzle moves when the extruder isn’t pushing material out.

5. Curling and rough corners

Corner curling

You will likely experience curling and rough corners when you print high-temperature filaments. The corners and edges curl because the layers are not cooled rapidly, allowing them to deform and form curved shapes.

The cause

Curling and rough corners are common issues when the 3D printing chamber/environment doesn’t cool layers quickly enough. For example, high-temperature filaments are soft in the chamber and prone to curling if not cooled.

Another cause of curling is parts not adhering to the print bed, which causes mechanical stress within the layers leading to deformation.

The solution

Make efforts to cool layers more quickly. Setting your heated chamber to a lower temperature can solve the problem, or you can adjust the extrusion temperature to make the filament less liquid out of the nozzle.

If curling occurs when you start printing, it’s possible that your build platform isn’t level or the first layer is printing too fast.

6. Weak infill 

Weak infill

Your 3D print’s infill is critical in its strength and rigidity. Infill is responsible for connecting the print surface to the interior, creating a semi-solid model. If the infill is weak, it can impact dimensional accuracy and integrity.

Nipping infill problems in the bud are essential to stem material wastage and ensure that all your models perform as intended.

The cause

Sometimes, 3D printers struggle with certain infills when fast print speeds overexert the extruder. Another cause is thin infill walls, which make parts lighter, weaken the infill structure, and make it snappable.

The solution

Try an alternate infill pattern and see if problems persist. Grid, triangular, honeycomb, cubic, and rectilinear are infills most 3D printers can handle.

You can also try printing with thicker infill walls, increasing print time but making it easier for the printer to work on complex shapes.

Lastly, try lowering the print speed directly. If you try to print infill too fast, the extruder can sometimes struggle to keep up.

7. Gaps between the infill and outline

Infill outline gaps

Arguably the most unsightly 3D printing mishap, gaps between the infill and outline signify that something is up with outline overlaps. Sometimes, printing too fast can also reduce bonding, causing the infill and outline to separate.

It is critical that the infill and outline bond for aesthetic and mechanical qualities – gaps are weak spots, making them detrimental to performance.

The cause

The most common cause is incorrect infill overlap parameter configuration in software, which puts too little material between the infill and outline – when it shrinks as it dries, it pulls away due to a lack of plastic.

Gaps between the infill and outline are also caused by too fast print speeds, specifically when the infill is printed faster than the outline. This doesn’t give the infill enough time to bond to the perimeter, making it shrink away.

The solution

Dive into your 3D printing software and look for the outline overlap setting. It is marked as a percentage. For example, an infill outline of 12% means that the infill will overlap with 12% of the inner perimeter. Increasing the percentage level for a higher infill overlap improves bonding.

If the outline overlap isn’t the problem, refer to your print speed. Fast print speeds, where you print the infill faster than the outline – or faster than the nozzle likes to operate for the pattern – can create gaps.

If you enjoyed this article about 3D printing problems, read our piece on designing parts for 3D printing and how to prepare your designs for 3D printing.

Find out more

Fancy some 3D printer training or expert advice? Contact the team at 01765 694 007 team@additive-x.com, or you can