Printer calibration inner holes

Hi I finished my reprap 2 days ago and its printing like a charm I Printed some calibration cubes and the xy achsis are of by about .1 to .2% Now I started printing objects with holes Coin Calibration thing (thing11270) I did set the coin size to 23.25 mm (1€ piece) and the holes came out about 21mm.


I'm printing with PLA 3mm
0.35mm nozzle
non heated bed (kapton tape as print surface)
Slic3r and pronterface

on the IRC some people said it might be due to shrinking but first of all I dont believe that it could be that much and second The outer edges should shrink too.
And I didn't change the steps per mm because of a print when calimrating the Reprap I calibrated it by dry movements of the achsis and measuring it with a calipher.

Anyone knows what I can do?

See [hydraraptor.blogspot.co.uk]

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[www.hydraraptor.blogspot.com]

The artikle is helpful and I will try making kompensations for all those errors but what I don't understand in this parametric coin calibration thing there are rectangular holes too which are to small too.

If rectangular holes come out too small that usually means the flow rate it too high so walls come out thicker than the slicer intends. However I am not sure about slic3r. Recent comments are that it changes the size of small holes but not big ones and it also changes the size of hexagonal holes between versions. I prefer Skeinforge where the gcode accurately matches the geometry in the STL.

Parts do come out small due to shrinkage. It is only about 0.5% I think.

Edited 1 time(s). Last edit at 06/15/2012 08:45AM by nophead.

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[www.hydraraptor.blogspot.com]