High temperature plastics such as ABS and PC require an ambient temperature of at least 50C to prevent them from shrinking too quickly during the print process. The contraction causes the part to either warp up from the corners or edges and result in a dimensionally inaccurate print, or even a catastrophic print failure from the nozzles catching on the part that has warped upwards.
We accomplish the high ambient temperature using an enclosure and making sure that the first layer of the part is the proper distance from the bed and is using the correct bed adhesive to get it to adhere properly. For larger parts, a warmer enclosure may be needed, but the components of the printer in the enclosure need to be rated for the temperatures they will experience otherwise they will eventually malfunction.
The photo below shows how a large part experiences warping and sometimes layer delamination (cracks between layers) if the ambient temperature of the printing environment is not warm enough.
Below is another basic example from a print that had several ABS parts on the bed. As you can see below, the corners of the parts look a little bent upwards because of warping from the parts.
Parts with high amounts of infill (>50%) have a greater tendency to warp due to internal stresses, as well as parts with large surface area as the contracting force has greater leverage to cause the part to warp.
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