Everything goes alright at the beginning, but the extruder step motor starts pulsing / jiggling in the middle of the job. I need to restart the printer (Printrbot), restart S3D and reconnect them, then everything is back to normal. Unfortunately it happens again when I start a new print. What would cause this problem? I didn't have such problem before using Repetier and Cura. It started happening after I installed S3D... Weird...
Please help. Thanks!