Failures are part and parcel of 3D printing, especially early on as you hone your skills. However, design challenges and spontaneous hardware hiccups and catch professional out too.
While there’s no way to guarantee zero failures, you can reduce them by knowing the common causes and acting on them.
For example, bed adhesion is the most common problem, followed by over-extrusion and under-extrusion, which have different fixes.
Nipping problems in the bud early reduces material waste, saves money, and helps you make better use of your time.
3D printing is the ultimate test of consistency because there are delicate balances to produce perfect models. This makes it a challenging manufacturing method, but you get a rapid production tool for unique creations in return.
This article reveals how to overcome the most common 3D printing failures to help you get the most out of your 3D printing experience.
Let’s jump in!
Bed adhesion is the ability of a 3D print to stick to the build plate during printing. Any movement from poor adhesion results in print failure because the print head will continue following the same path in the print file.
Imagine a car following a straight road, the road throwing a curve, and the car ploughing straight on. That’s what happens to your print.
There are four possible reasons for poor bed adhesion:
- The print material (e.g., nylon)
- The surface material (e.g., glass)
- The bed isn’t level
- The print bed’s temperature (e.g., 90 degrees Celsius)
The first reason – print material – defines your approach to the second and third reasons because all materials can be temperamental.
In any case, you have three possible solutions:
- Use bed adhesives like Elmer’s glue or build plate tape to form a stickier layer for prints to adhere to.
- Print a ‘brim’ so your model prints on a layer of plastic rather than directly on the build plate.
- Try raising and lowering the bed temperature in increments of 5°C. You want the first layer to bond to the build plate quickly.
Over-extrusion is when too much plastic is extruded to produce the model, creating blobs, stringing, and other surface imperfections.
Over-extrusion can also jam the nozzle and create waste, making it challenging to keep costs down and print sustainably.
The truth is that most 3D printers do not monitor how much plastic is extruded and rely on extrusion settings to keep things in check.
The solution is to configure your extrusion settings correctly. For example, you can decrease the extrusion multiplier for over-extrusion issues.
Here are the solutions we recommend trying:
- Lower your extrusion multiplier in 2.5% increments
- Reduce the nozzle temp in 2°C increments to make the filament less viscous
- Double-check the filament diameter and corresponding settings
Under extrusion is when too little plastic is extruded, which can create visible layer lines, missing layers, gaps, and semi-solid structures.
In many cases, the fix for under-extrusion is the opposite for over-extrusion. For example, you can increase the nozzle temp in 2°C increments.
You should also check the nozzle and Bowden tube for clogging since a low temperature can make the filament stick to components it passes through.
If your models have thin or missing layers or gaps or are otherwise fragile, you probably have an under-extrusion problem.
Incorrect bed levelling
An unlevel print bed can cause many problems, including print bed adhesion failures, warping, surface imperfections, and layer adhesion issues.
While some 3D printers have automatic bed levelling and can position the nozzle automatically, the printer doesn’t always get things right. You might have to manually compensate for an uneven work surface.
Manual bed levelling requires a feeler gauge or an aluminium card to determine the distance between the nozzle at points across the bed.
You run the gauge across all four corners and repeat the process as many times as necessary to ensure that you get the same height for all the corners.
Otherwise, you can rely on your printer’s automatic bed levelling feature.
Another innovation is adaptive bed levelling from Markforged, which makes Z-axis adjustments in real time to correct unwanted bed movement during the print process.
Gaps between layers
Gaps between layers are relatively common in 3D printing, especially when printing thinner layers at low temperatures.
The low bonding strength between layers is associated with low nozzle temperatures but can also be caused by fast print speeds and incorrect layer heights.
This all comes down to two possible problems: either defective material being deposited or the foundation for the layer isn’t solid enough. Both problems create visible gaps between layers and have different fixes.
- For first-layer gaps, the cause is usually an incorrect nozzle height. The nozzle must be close to the build plate to form the first layer.
- For top layer gaps, insufficient cooling is the leading cause. Try increasing your cooling configuration to promote cooling.
- Under-extrusion. Try increasing the nozzle temperature in 2°C increments and increasing your extrusion multiplier.
- Temperature changes. You must provide a consistent environment if your 3D printer doesn’t have an enclosed build chamber.
- Fast print speed. Too fast a printing speed can create gaps between layers due to adhesion issues. Try reducing your print speed.
- Slow feed rate. If your extruder doesn’t feed the nozzle with enough filament, gaps will form due to a lack of material.
Layer shifting happens when the printer attempts to move the nozzle to a specific location but is involuntarily moved out of position, causing the printer to print in the wrong location and creating parts with layer shifting.
For example, bumping into your 3D printer or slamming a door can knock the tool head to a new position, and some printers are more sensitive than others.
It’s crucial to recognise that most 3D printers have no feedback to detect this, so they keep printing as if nothing has happened.
Another common cause of minor layer shifting is the tool head moving too quickly, which can overload the stepper motors, causing positional problems. Try adjusting the X/Y axis movement speed controls and see if it helps.
If your layer-shifting problems continue, don’t discount electrical and mechanical faults, especially if your printer has taken a knock or is over three years old. Stretched belts and loose screws can cause erratic movement of the tool head.
If you enjoyed this article, discover the 7 most common 3D printing problems.
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