If you want a strong, reliable 3D printed part, layer adhesion and proper bonding is needed. Without this, you are likely to experience layer separation, splitting or delamination of your parts, or in simple terms, layers not sticking together.
Getting your layers to stick together in your 3D prints is important for getting a successful print that you can be proud of. There are some main issues that cause this layer separation, so if you are experiencing this, the following article should help you solve this problem.
The best way to get layers to stick together for your 3D prints is to do a series of slicer tweaks such as increasing printing temperature, decreasing printing speed, adjusting your cooling fans, increasing flow rate. Use trial and error for these settings with printer calibration tests.
There is more detail that is necessary for you to really know how to deal with this issue. I go into exact ways you should trial and error these settings, as well as give some good printer calibration tests so keep reading for this key info.
Why Do 3D Printer Layers Not Stick Together?
When your 3D printer layers don’t stick together, this is also known fancily termed, layer delamination.
It’s basically when your 3D printed layers are having physical issues layering on top of each other evenly, but it can happen for a number of reasons. The usual reason is because the melting of your filament isn’t being done adequately.
Your filament needs to be able to flow with an ideal amount of viscosity or liquidity so if your filament can’t get there with the right temperature, it can easily lead to layers not being able to stick together.
Other than that, it comes down to abrupt changes in temperature from cooling, under-extrusion or not giving your 3D printed layers enough time to settle and bond with each other. Fixing underlying under-extrusion issues can definitely help out.
When your layers are extruded at the necessary hot temperature, it can cool and shrink which puts pressure on the layer below it. With high levels of cooling that pressure can build up and cause layer separation.
A few setting changes in your slicer should be able to solve your 3D print layers not sticking together.
I will go directly into what you can do to solve this issue.
Increase Your Printing Temperature
The best solution that works for most people experiencing this issue is to increase your printing/nozzle temperature. Your filament needs to be melted enough to adhere to each other properly, so a higher heat will help that process.
Your best bet is to print out a temperature tower, where you gradually change the printing temperatures while it is printing. You should change them in 5C increments until you find the sweet spot that produces print layers that stick together.
3D printer filament do have a fairly wide range of temperatures that work for it, but depending on the brand, color and other factors, it can make a difference.
Using a temperature tower should be able to get you to your perfect temperature in just one print.
The temperature tower I use is the Smart Compact Temperature Calibration Tower by gaaZolee on Thingiverse. This was made because many of the other temperature towers out there were just too bulky and took a while to print out.
This one is compact, made for many materials, and contains a number of calibration tests such as overhands, bridges and stringing all in one tower.
Adjust Fan Speed & Cooling
A cooling fan which isn’t working at its optimal efficiency can definitely contribute to your 3D prints not sticking together. If you find that other fixes aren’t working, this could be your issue.
What you can do in this instance is to print out some kind of duct specific for your 3D printer to help direct the cool air directly to prints. You don’t want huge changes in printing temperatures, rather a consistent temperature.
That should help out quite a bit, but you can also get yourself a more efficient fan altogether. One that is well-known and respected in the 3D printing community is the Noctua NF-A4x10 Fan from Amazon.
It’s currently rated 4.7 out of 5 stars with over 2,000 individual customer ratings, most of which are from fellow 3D printer users.
Not only is it a quiet cooling fan, but it is built for optimal cooling and power which you can easily control in your slicer.
Different materials require different levels of cooling. For a material like ABS, it’s sometimes recommended that you totally turn your fans off so it doesn’t warp, having a better chance to print successfully.
Nylon and PETG also aren’t big fans of cooling fans, so using your cooling fan at a rate as low as 30% can be advised for these materials.
Increase Your Flow Rate
Increasing your flow rate isn’t an ideal fix to go with straight away, because it’s more of a symptom fixer. On the other hand, it can work pretty well to help bond your layers together.
Increase your flow rate or your extrusion multiplier means that more filament is being extruded. This gives your print layers a better opportunity to adhere to each other, resulting in less separation and stronger layer bonds.
It can cause over extrusion if you go overboard, so increase this in small increments. Increments of 5% per print should be enough to find that sweet spot for non-separated print layers.
Also, changing your extrusion width to above your normal nozzle diameter can combat the shrinkage of your filament.
Decrease Your Printing Speed
The same way your 3D printer temperature can cause layer separation, so can your printing speed.
Your prints do need time to settle in with each other, so they can peacefully bond before the next layer comes in.
If your prints don’t have the time to bond properly, layer separation or delamination can occur so this fix is definitely one to try out.
This is pretty self-explanatory, slow down your printing speeds in small increments, 10mm/s should be fine to test out.
There are speeds that 3D printer users usually stick between, which does vary between printers. For a casual Ender 3 which I have, I find sticking anywhere between 40mm/s-80mm/s works out fairly well.
There are also speed calibration towers that you can print with to find your ideal printing speed.
The speed tower that I use is the Speed Tower Test by wscarlton on Thingiverse. You use a starting speed of 20mm/s and alter printing speed at 12.5mm up the tower. You can set up instructions in your slicer to ‘Tweak at Z’ to alter print your print speeds.
Decrease Your Layer Height
This one is a less well-known method to fix your layers not sticking together. There is a usual layer height that is advised, dependent on what nozzle diameter you are using. At a certain point, your new layers won’t have the necessary bonding pressure to adhere to the previous layer.
A good guide to follow in terms of this is to have a layer height which is 15%-25% lower than your nozzle diameter for a successful print. The usual nozzle diameter you’ll have is a 0.4mm nozzle, so I’ll use that as an example with a midpoint of 20%.
For a 0.4mm nozzle:
0.4mm * 0.2 = 0.08mm (20%)
0.4mm – 0.08mm = 0.32mm (80%) of nozzle diameter.
So for your 0.4mm nozzle, a 20% decrease would be a 0.32mm layer height.
For a 1mm nozzle:
1mm * 0.2 = 0.2mm (20%)
1mm – 0.2mm = 0.8mm (80%) of nozzle diameter
So for a 1mm nozzle, a 20% decrease would be a 0.8mm layer height.
Using a layer height above this gives your layers less chance to properly adhere to the previous layer. Many people overlook this so if you see that your layers aren’t sticking together, try this method out.
Use An Enclosure
As previously mentioned, having a consistent printing temperature is ideal for many 3D printed materials. We don’t want external factors negatively affecting out prints, because they can cause layer splitting or print layers separating.
PLA is less affected by these external influences, but I have had instances of PLA warping from drafts and breezes that came through the window. An enclosure is great to protect your prints from such things and is more likely to give you better quality prints.
A great enclosure that is gaining a lot of traction is the Creality Fireproof & Dustproof Warm Enclosure. It provides plenty of protection, noise reduction, but most importantly, that constant temperature printing environment to reduce the presence of print layers not sticking together.
Due to popular demand, they’ve also included a larger version for those bigger 3D printers out there.
Use a Draft Shield Setting
Cura has an experiment settings option called a Draft Shield which builds a wall around your 3D print. The goal of this is to trap hot air around your prints to solve warping and delamination issues, so it’s made specifically for our main issue here.
The first section of the video below goes over this Draft Shield option so check that out if you are intrigued.
I hope this article helps you to solve the frustrating issue of your 3D prints separating during the printing process. With a little trial and error, you should be able to put this problem behind you and get some great looking prints.