Layer separation, also called delamination, is a common 3D printing issue caused by poor layer-to-layer adhesion.
To avoid ending up with drastically flawed models – and wasted resources and time – you must learn what can cause this problem and how to prevent it.
3D print layer separation can be caused by inadequate layer width or height, too fast extrusion or too slow flow rate, incorrect printing temperature, or poorly heated bed. Low quality or wet filament can also cause the layers to separate. External factors and a clogged nozzle are other potential culprits.
Read on to find out what can cause ABS and PLA adhesion problems and how to solve the issue.
What Is Layer Separation?
Layer separation is a 3D printing phenomenon caused by subpar layer bonds. Weak bonds result in the 3D print layers not sticking to one another.
The issue may be visible straight away, or the model can start cracking later on. Regardless, once the delamination process starts, the layers will keep splitting until complete separation.
Layer separation can obviously cause cosmetic problems, but the incomplete bonds can also affect the model’s durability and resistance.
This not only means a ruined artistic print, but the implications could be worse if you’re making parts for medical or technological use.
13 Reasons Why 3D Printing Layers Are Not Bonding
As explained, layer delamination can be caused by weak layer adhesion. This phenomenon can happen at any moment while you’re printing.
When the first layer doesn’t adhere to the bed, the base of the model will appear to be warped. When subsequent filament layers don’t adhere to one another, they tend to separate, resulting in cracks.
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Below, the most common layer delamination causes and how to solve them.
1. Layer Height
A common mistake among 3D printing newbies is selecting the maximum layer height for the used nozzle.
For instance, when using a 0.5 mm nozzle, you may be tempted to input a layer height of 0.5 mm.
However, when the height of the extruded material is as thick as the nozzle diameter, the extruder might not be able to press the new layer into the layer below. Thus, the material won’t adhere properly, resulting in delamination.
Solution: Reduce the layer height
As a rule of thumb, the layer height should be at least 20% smaller than the nozzle diameter. So, for a 0.5 mm nozzle, the layer height shouldn’t be larger than 0.4 mm.
You can reduce the layer height even more. Keep in mind that the smaller the height, the greater the number of details your machine can print and the better the adhesion between layers.
Also know that the rules above don’t apply to all filaments. TPU layer height shouldn’t exceed 0.1 to 0.2 mm, for instance.
2. Printing Temperature
Setting the right printing temperature for the material you’re using is key to obtaining quality models. However, if you’re using several types of filament, forgetting to change the settings is easy.
Sometimes, you may also fail to check or change the temperature settings when switching from one brand to another, since different brands can sometimes recommend different temperatures.
Solution: Check and set the correct temperature
More often, layer separation problems occur due to too low rather than too high temperature. So, if your model cracks and you can easily spot the lines between the layers, the extrusion temperature is likely low.
Check the range for the material you’re using and compare it to the temperature set in your software.
Raise the temperature as needed, and don’t forget to check the temperature of the heated bed as well.
While the temperature of the building surface only affects the bottom layer, a cold bed could cool down the first layer too fast and the second layer might not adhere properly. This typically results in warping and an inconsistent model base.
3. Cooling Fan
As mentioned above, too fast cooling can negatively affect layer adhesion.
While a cool building surface can speed up the cooling of the first layer, a cooling fan set on max speed could cool down all subsequent layers too fast.
If this happens, the layers may not have sufficient time to fuse and bond, resulting in layer separation.
Solution: Decrease cooling fan speed
Most 3D printing interfaces have the default cooling fan speed set at 100%, which basically means top speed.
If you’re noticing separation problems, decrease the speed by 10% at a time until your parts print and cool down correctly.
Some temperature-sensitive materials, such as ABS, may not require cooling at all. Thus, don’t be afraid to go all the way down to 0% based on the type of filament you’re using.
4. Flow Rate
Another factor that can cause improper bonding is the flow rate – or extrusion speed.
In ideal situations, the flow rate enables you to adjust how slow or fast the filament is fed into the extruder, helping avoid under- or over-extrusion.
In less-than-ideal situations, you may forget to adjust the flow rate to the material and printing speed, resulting in under-extrusion.
When the filament is fed too slowly, the laid line cools down before the new layer is extruded on top of it. The lack of temperature inhibits proper bonding and results in delamination.
Solution: Increase the flow rate
If you’re sure you’re printing at the correct temperature and that the cooling fan’s speed is right, increasing the flow rate could help prevent layer separation.
Increase the flow slowly, in 5% increments at time. Increasing too much would result in over-extrusion, which wouldn’t lead to layer separation but would create subpar prints nonetheless.
If you’ve gone from under- to over-extrusion and delamination still occurs, the culprit could be the print speed rather than the flow rate.
5. Print Speed
Something 3D printing newbies often confuse is the flow rate and print speed. These two factors are closely related, but different from one another.
The key secret here is to set the extrusion speed to the exact parameters recommended by the manufacturer – if you don’t have the original filament packaging, just google the filament’s name to find the specs.
Generally, layer separation is caused by too fast rather than slow speed.
Solution: Lower the print speed
While it may sound counterintuitive – a slow speed allows the material to cool down before the next layer is extruded – a too high printing speed can cause delamination.
If you don’t have the filament specs and can’t find them, decrease the speed by 5 to 10 mm/s at a time. If you’ve lowered it by about 50% of the original value and layer separation still occurs, the problem may be elsewhere.
6. Nozzle Diameter
We mentioned the layer height and how it should be smaller than the nozzle. Surprisingly, though, the actual size of the nozzle can also impact layer bonding and lead to delamination.
Typically, the smaller the nozzle, the higher the chances of layer separation.
This happens because a small nozzle diameter results in a thin line. The reduced thickness limits the contact surface between the layers, weakening the bond.
Solution: Use a larger nozzle
It is easy to understand that a larger nozzle can lay thicker lines, increasing the contact surface between the layers. Thus, the bonds are stronger and the risk of layer separation is lower.
Considering the layer height recommendation above – the layer height should be at least 20% smaller than the nozzle diameter – you should use nozzles that are at least 0.5 mm wide.
In fact, a 0.5 mm nozzle is perfect for most 3D printing projects, which actually require a layer thickness of 0.4 mm. A 0.4 mm nozzle is ideal for projects that require a line thickness of about 0.3 mm or thinner, whereas a nozzle of at least 0.6 mm should be used for models with thicker walls.
7. Clogged Nozzle
Talking about nozzles, a crucial thing to check before making any adjustments is the state of your nozzles.
A dirty or clogged extrusion tip could create under-extrusion, which – as explained – can be responsible for layer separation.
Solution: Clean/replace the nozzle
To prevent layer separation, clean your nozzles after each project.
Use a damp cloth or alcohol wipe to remove excess filament while the hotend is still hot. If any material remains clinging, use a needle, wire brush, or small blade to remove existing debris.
If you can’t clean your nozzle properly – perhaps due to too much material build-up – replace it with a new one.
To improve adhesion and printing results, also make sure the building surface is clean.
8. Poor Bed Adhesion
A dirty building surface is not the only bed-related thing that could lead to layer separation. Improper adhesion to the building surface is responsible for warping, but it can also be a reason for delamination.
In fact, if the first layer doesn’t adhere well to the bed, it can get deformed. The line on top of it won’t be laid properly, as the extruder will follow the model specs. This could lead to a deformed second layer that didn’t bond with the base to begin with.
All new layers won’t benefit from a solid base on which to build up, and separation is very likely to occur.
Solution: Improve bed adhesion
In most cases, all it takes to improve bed adhesion is a coating on the surface. Blue tape or painter’s tape are common choices. Cheap hairspray applied right before printing can also do the trick.
If your printer bed is of really poor quality, consider replacing it.
9. Low Infill Density
When printing solid-core models, a low infill density is another factor that could lead to layer separation.
Infill density – as you might imagine – is the amount of material used inside the print. The higher the density, the more filament goes inside the core.
Considering how expensive some filament types can be, you might want to save a buck and use a lower infill density for some solid-core models.
However, the lower the density, the poorer the adhesion between the layers and the higher the risk of delamination.
Solution: Increase infill density
Using a higher infill density comes with several advantages. In addition to lowering the likelihood of layer separation, it can also increase the overall strength and durability of the print.
However, too much material inside the print could have a negative effect on the model balance during printing, especially if it is an intricate part.
To prevent errors, add more density in small increments – about 5% to 10% at a time and no more than 50% of total added density compared to the initial setting.
10. External Factors
If you’ve got all settings right but the layers still separate, the problem could be attributed to external factors.
Stronger air currents from an open window or fan could affect the quality of your print. Vibrations from the printer could also prevent proper bonding.
Solution: Create “ideal” printing conditions
For the best results, it is recommended to use building surface enclosure that limits the impact of environmental conditions on your model.
Also consider using rafts and supports to increase stability during printing. These accessories absorb the vibrations from the printer and keep the model still as the layers build up one on top of the other, enhancing bonding.
11. Wet Filament
Some filament types, such as PLA, nylon, and PVA, are hydroscopic. They absorb moisture from the environment when stored out of their package.
Wet filament loses most of its properties and produces poor quality parts. Layer separation is very likely in these cases.
Solution: Store the filament correctly/dry the filament before use
If you don’t want to waste filament and throw your hard-earned money out the window, invest in a dry box. Keep your open filament in it and store new, unopened filament in a cool and dry room.
If you suspect the filament is wet, you can dry it in the oven for four to six hours. Set the temperature to:
- 104 to 113°F for PLA
- 176°F for ABS, PVA, or nylon
Alternatively, you can dry the filament in a specific filament dryer or food dehydrator.
12. Filament Quality
Wet filament is not the only filament-related thing that could cause delamination. Poor quality filament may not produce satisfactory results no matter how hard you try.
Solution: Buy quality filament
Quality 3D printing filament can be expensive, but it can help you save money in the long run. Mid-range options may also be worth your money.
A few trustworthy brands include Hatchbox, Prusament, Proto Pasta, ColorFABB, MakerBot, and Eryone.
13. Model Orientation
Not many people know that the model orientation on the building surface can also determine the outcome – including the probability of delamination.
Solution: Make sure your model is oriented correctly
There are three essential things to remember when positioning the model: avoid overhangs, avoid high-stress areas, and orient your model perpendicularly to the building surface.
Overhangs can put pressure on the model and cause layer separation. High-stress areas in a model usually consist of corners and thin walls, which should be supported properly to ensure proper bonding.
Printing the model perpendicularly onto the building surface can improve stability and balance. The layers are also extruded in a natural motion, increasing adhesion.
Ideal Temperature To Fix Poor Adhesion in ABS, PLA and PET-G Layers
One of the most important things to prevent layer separation is printing at the ideal temperature. The ideal temperature can differ from filament to filament. The ranges below work best for the most common types of filament.
ABS is a popular 3D printing material, but it is highly susceptible to layer separation. This material melts at around 210°C and requires an extrusion temperature between 230°C – 250°C.
To keep ABS layers from not bonding, heat the bed to 100°C and turn off the cooling fans completely.
PLA not sticking to itself is a common issue when the printing temperature is insufficient.
Ideal conditions for PLA vary from 180°C to 230°C. The material doesn’t require a heated bed, but if your printer has one, heat it to about 60°C to improve adhesion.
When adjusting the temperature, raise it by 5 degrees at a time until the layers bond properly.
An alternative to ABS, PET-G is a popular choice for printing larger objects. PET-G delamination is rarer compared to ABS, but it still depends on proper temperature.
PET-G has the same requirements as ABS: 230°C to 250°C extrusion temperature and a bed at around 100°C. The main difference is the cooling fan, which should be set at 100%.
Layer separation is a common 3D printing problem. Improper bonding and delamination can happen for a variety of reasons, most of which are related to the printing settings.
If all settings are right and the part still cracks, consider environmental factors and the filament quality. Also, don’t forget to store the filament correctly.
We hope this guide can help you fix the layer separation problem.