Why do some 3D prints curl off the build plate?
One of the difficulties many customers have with desktop 3D printers is curling/warping. Curling and warping of parts is caused by the material cooling unevenly as it prints, causing some of the part to curl. Industrial 3D printers have heated chambers to reduce this effect, but desktop 3D printers do not. Some have heated beds, which helps, but isn't a perfect solution either. In this article, we'll look at the contributing factors and discuss techniques that can reduce this curling effect on the MakerBot Replicator+.
Contributing Factors:
Build Plate is out of level
If your build plate is not level, your first layer is not adhering to the build plate properly. If the build plate is too far away, the material looks wavy on the build plate and has not adhered properly, making it very easy for the part to lift off the build plate. If the extruder is too close, you'll generally get filament slips or clogs. Below are a couple of pictures showing what it looks like when the extruder is too far away vs perfect on the first layer:
Grip Surface is worn out
A new grip surface feels rough to the touch. This helps the first layer stick and hold as the part prints. As the grip surface is printed on over and over again, it will begin to wear and become smooth. A smooth grip surface does not hold the first layer as well, increasing the chances that the part curls. Below are pictures of a well used grip surface vs brand new ones. These are simple to replace, you just need to peel the grip surface off and replace it. You do not need to change out the entire build plate.
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Worn out grip surface
| Brand new grip surfaces
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Environment
If the room is very cold, or if there is a draft blowing across the print bed, this also will increase the likelihood that the part will curl. Positioning the printer in the room is important. For example, a printer next to a window on a cold day may end up resulting in more curled prints than on a warm day. A printer under an air conditioning vent will also tend to curl more. Some customers have designed enclosures for their printers to help manage the environment, but sometimes simply placing the printer in a different area of the room can be use as effective.
Old/Wet Material
3D printer material absorbs moisture from the air if left out in the open. Ideally, you will store your printer in a sealed bag with desiccant packs to reduce its exposure to moisture. There are many examples of people making dry boxes for material storage online for $20 or less by using a plastic bin with a gasket on the lid and desiccant packs.
Extruder is worn out/faulty
The extruders last roughly 700 print hours and are a
consumable. It is a good idea to double check that the extruder isn’t contributing to the problem
by printing the same part with a different extruder and seeing if there is any
effect on the curling. If you have multiple printers running at the same time
and they are both curling at the same area, then the extruder is unlikely to be the culprit, but if you are only running one printer you can’t really
know that unless you swap the extruder.
Tips to Reduce Curling:
Even if you have a perfectly level build plate, a new
extruder, a fresh grip surface and good material, sometimes parts still curl.
What is going on is that the part is cooling unevenly and that causes it to contract
unevenly, resulting in portions of the part warping. So what do you do in this situation?
Glue Stick:
Some tech support
people you talk to will tell you don’t use it, others will say to use it. We have had good success with this technique as long as you don’t over do it and
you clean off the built up glue every 2 or 3 prints. An Elmers glue stick works well and can be cleaned off using a wet paper towel.
Helper Disks:
This technique also works well, but sometimes it isn’t possible if the part
is already big enough that it takes up most of the build plate. The concept is
that you put a coin shaped STL file behind the portion of the part that tends
to curl to extend the raft further away from the actual part. Then what curls
is the helper disk and not the part.
You can insert helper disks directly into MakerBot Print by
going to File>Insert Example Prints>All Printers and pick either small or
large helper disk. Here is a support article about them:
https://support.makerbot.com/learn/makerbot-print-software/using-makerbot-print/helper-disks_13632
Base layers:
Changing the base layer of your print can help as well. You can access the base layer options in Makerbot print by clicking custom settings from the print settings menu and then quick settings. Within Makerbot Print you have several options. You can choose no base layer (not recommended, especially if you're having part adhesion issues), Raft, Padded Base, and Padded Base + Brim. Makerbot uses a raft by default. Rafts provide a platform for models to adhere to the build surface and even out the first layer.
If you're using a raft and the other methods mentioned haven't helped, consider changing to Padded Base or Padded Base + Brims. When you select a padded base, the first layer of the model is extruded a bit thicker. The result is thick lines on the bottom, but a better result with regard to adhesion. To further help with adhesion you can add a brim to the padded base. A brim is a 1-2 layer thick pieces that extends from the perimeter of your object and will further increase the surface area of the print contacting the build sheet. Note that the brim will need to be manually removed after the print.
Tape:
We have seen some customers use this method successfully, but it tends to work best when you are printing the same part over and over again and know exactly where the part tends to curl. You can tape
down the raft right after it finishes printing in the area where it is likely
to curl. You need to experiment with this a bit to get it right, but in the right situation it can make a big difference. It is a good idea to try all the suggestions above first before using this technique. The image below shows an example of where a customer has put tape on the build plate right after the raft has finished.