Height Reduction Rostock

bjl1973

HI everyone,

I have an issue that I believe is a firmware problem, but looking for advice to narrow it down.  I have modified my Rostock Max v1 for high accuracy using 1/32 step rate with Arduino Due/RAMPS-FD controller setup. I have the bed level to within 0.05mm with a nozzle height of 0.2mm.  When I print my first layer, the perimeter is perfect, but when it starts the infill (45 Degree Lines) the nozzle will slowly get closer and closer to the print bed until it either tears the tape or stop laying material down, but only on the right side of the print. The Pic explains it better than I can. See Pic I have also noticed that the head will start to pull away from the perimeter at the same time.  Visible down the right side of the pic.  It appears to be a cumulative rounding error (adding/subtracting rounded numbers together) just from my experience from C programming which may or may not be repairable.

Any suggestions welcome.

Repetier

What version are you using? You should definitely use latest 0.92 in your case. It has 64 bit integer support so you do not get rounding errors with higher resolutions.

On the other side, it is the same position computation as for the outline, so there is no difference to expect.

Have you created a height map, to see error distribution?

Yesterday 0.92 version also has a bump map correction, that might come usefull to eliminate last 0,05mm error. Just call G29 when configured to create and use the bump map.

bjl1973

I am at Version 0.92, but it is a month or two old.

At present, I do not have a reliable z-probe setup to do that.  I use a boro-scope mounted on the platform to check my nozzle height to the glass/tape.  I can live with the 0.05mm error in the bed leveling, it is the gradual height change when printing that I am having issues with. The picture I linked to in the original post can explain it better than I can.

Thanks,

MShievitz

sounds like a stepping/calibration problem try changing steps per mm?