Front door for UM2 & UM3 in Help, Tips & Tricks Posted June 22, 2018 · Edited June 22, 2018 by 3dp4me Closes the space of your Ultimaker. Thus, constant temperature conditions can be achieved. These are especially important when using ABS material. It also prevents the material from cooling too quickly and minimizes the warping effect. The handling is very simple. Open the locks with the two knobs and pull the door upwards.