CNC router on the cheap

[eried]

(04-30-2016 11:40 AM)Vtile Wrote:  What is the material of the bed? Try to use tempered or boron glass?? If the bed is metal and needs to be I would try to search some material that have extremely low heat expansion coefficient and even then counter the natural heat bending by making it floating and heated evenly by some way. The glass bed is something I have seen in the pictures of some supposedly? high dollar machines, not my invention in any means. One cheap source of nonstick and flat small bed might be also a bottom of a suitable teflon or ceramic frying pan.

The bed is made from aluminium. I can't use glass because I need an induction sensor to sense the bed for the auto leveling.

Cheap flat things aren't that flat as you imagine. This aluminium bed looks quite flat to the eye. I need it to be flat up to 0.05 mm or at least 0.1 mm in heights differentials