It is not a new issue that 3D prints sometimes move or lose adhesion from the build plate. Sometimes the most frustrating moments come hours into a print when the part seemingly just decides it doesn’t want to adhere to the bed anymore. 99% of the time there is a really good reason why a print fails and sometimes the simpler the reason the more frustrating it can be.
The most common reasons a 3D print moves and loses adhesion to the build plate are the 3D printer bed not being level, part bed adhesion, a dirty build plate, 3D printer belt tension, part height to width ratio, print speed on the first layer, and collision with a foreign object.
Here are my top 7 reasons that your 3D print is moving mid print and also some solutions to help with your next 3D print.
If your 3D printer is just creating a jumbled mess of filament that more closely resembles a bird nest than a nice clean first layer then you probably have a bed level issue.
Your bed level is the utmost important thing to get right to ensure a perfect 3D print. You can be off a few degrees on your temperature but if you are off even .020 on an inch on your bed level you will likely never achieve a good 3D print.
For more information on how to level a bed check out this article.
If your 3D printer automatically levels the bed then other than double checking that your machine is leveling the bed properly you should not have to worry about your bed level
Bed adhesion can play a huge role in the success of a 3D print and can be a determining factor if your print is moving on the build plate and failing. If the print is not achieving proper bed adhesion on the first layer your print will likely fail.
You can improve your bed adhesion by applying texture to the surface with painters tape or a PEI bed, using stick glue to bond the print to the surface, or by using the raft or brim function in your slicer.
Painters tape is a great way to add texture to your build plate if you are using a glass build plate. Simply apply a layer of painters tape to the bed and make a minor Z shift to compensate for the thickness of the tape. Painters tape is typically .10mm-.12mm thick so if you do not adjust for the thickness of the tape your nozzle will be too close to the build surface and you will not get a good first layer.
PEI (Polyetherimide) is a thermoplastic similar to PEEK that for 3D printing is traditionally sold as a textured sheet that you then magnetize to your build plate. PEI is great for large flat prints that achieve too much bed adhesion on glass as well as smaller more intricate prints that need the additional bed adhesion.
Here is a PEI sheet that I recommend that works for Ender 3, Ender 3 V2, Ender 3 Pro, Ender 5, and Ender 5 Pro. Amazon.
A raft or brim is another great method for obtaining additional bed adhesion. Essentially all that a raft or brim does is increase the area that the print contacts the build plate therefore creating more surface tension.
For more information on creating rafts and brims check out this article.
If you cannot remember the difference between a skirt and a brim just think of a brim like the flat brim of a hat.
Dirty Build Plate.
Your build plate should be regularly cleaned with isopropyl alcohol or with soap and water. If your build plate is dirty or dusty this creates a bad environment for the 3D print to adhere to the build plate and that dust can get between the build plate and your first layer and will compromise adhesion.
If you use stick glue you should be rinsing off your build plate and scrubbing it with soap and water between prints.
Belt tension is a common cause for layer shifting. If your belt is too loose the servo controlling that axis will turn but it will not engage the belt which will cause the 3D printer to lose the true X and Y zero which will cause layer shifting.
Shown below is an extreme case of layer shifting that failed in an amazing fashion.
Most 3D printers that are belt driven have belt tensioners built as a factory stock option but other printers you will have to disassemble the end of the belt tension line and tighten the belt yourself.
Part Height To Width Ratio.
The height to width ratio of your 3D print can affect whether your 3D printer is able to successfully complete your 3D print. If your print keeps falling over mid print there are a few ways to secure your print to ensure that you will not lose prints mid run.
If you are printing a very narrow and tall print (as shown below) it is very easy for the 3D print to fall over and lose bed adhesion. The simplest fix for this is just to increase bed adhesion with tape or a raft but if you need extra you can print a sacrifice tower.
Sacrifice tower –
A sacrifice tower is essentially a large pillar that runs parallel with your 3D print that you can connect to your thin print to give it additional stability.
Painters tape –
Use painters tape on your build plate to achieve better bed adhesion. Painters tape is textured which can achieve better bed adhesion and surface tension with the build plate.
Print Speed On First Layer.
Slowing down your print speed on your first layer can help your printer create more defined lines as well as give the 3D print time to cool before moving on to the next sequence. If you are printing your first layer too fast the printer can seem to cut corners but what is really happening is the material is still slightly soft and is dragged around causing a radius instead of a crisp corner.
Most slicer default settings are to print the initial layer slower but if you are struggling you can change the speed at the machine for some printers and you can also change the speed of the initial layer in basically every slicer.
If your print is inexplicably failing at the same location every time consider checking for parts of your printer that might be colliding with the part. It is possible for belts, cables, or surrounding objects to collide with your 3D print and cause a failure in your print. Always make sure that your printer’s surroundings are clear of foreign objects.
Essentially all of these strategies could be used on every print and you should be familiar with how each of these should . If you are still struggling to keep your part from moving mid print consider using a combination of the bed adhesion techniques.