FAQ: How do I prevent my product from warping?

From time to time, our helpdesk encounters the question how to prevent products from warping.
Especially with ABS, but also with less common materials as nylon, the material tends to deform
while printing. This leads to ruined products and sometimes even a ‘hard hit’: the printer head
bangs into the curled up material. This is something you would want to prevent!

Why does a product warp?

A print deforms because the material shrinks when it cools down. How much the product reduces,
depends on the shrink factor of the material. Because the print bed is nice and warm, the material on
the bottom will reduce the least. The higher a product reaches, the more it shrinks. This difference
causes tension in the material and in the end a warped model. Warping can occur on two places in
the product. Firstly there’s de-lamination, when two layers in the model split and a crack appears.
This is mostly caused by layers not sticking together properly. When you use the right settings,
de-lamination shouldn’t occur. The second variant is warpage at the bottom of the product. This is a
more persistent problem, but luckily there are a few methods to prevent this from happening.

 

Place a raft

When you use a raft, a few layers with little infill will be placed under your product. This causes less
differences in shrinkage and less tension at the bottom of the product. And when warping does
occur, this mostly effects the raft instead of your product. Therefore, it’s important that the raft is
bigger than your product, to make sure that it will not cause problems when the corners curl up.

Temperature

Temperature control is very important when combatting warping. Choose a printer with which the
product cools down as gradually as possible. A conditioned, closed casing is essential. This way, you
have control over the temperature within the printer to minimize the difference in shrinkage.

‘glue’ your model to the print bed

With warping, two forces oppose each other: the pulling strength from the shrinking upper layers,
versus the pulling strength from the print bed. Simply put: when the bottom sticks tightly to the print
bed, it won’t curl up easily. There are a few tools we can think of to fixate the model to the bed. A
common method is using a slurry that functions as a glue. You can make this slurry yourself with
acetone and ABS. But be careful though! When you use too much of this glue, you can’t (easily)
remove the product from the print bed. Result: broken glass plates. A safer option is using specialized
tools like PEI sheets. These firmly hold on to your print to prevent it from warping, but the model is
still easily removed after printing.