Instead of building closed heated chamber I've added 3 cheap halogen projectors with 150w lamps. With these there is no warping while printing pc-abs at 280c (bed is at 130 C). Detail on attached pictures is ~12cm long, 6mm thick. The bed thermistor shows 50-60 C within 20 minutes if I power on the projectors (bed heater is off). Electronic parts and motors are on top of the printer, so they are not being heated. I didn't try to print with other materials yet, but pc-abs warps badly without projectors.
Edited 1 time(s). Last edit at 12/26/2016 06:49AM by Dasdsddasdf.