Solution: Read on...
If for one reason or another your Printrbot is not accurately reproducing your 3D models to the correct size or proportion, it may be that it needs calibrating. You should first familiarise yourself with the printerbot, the software and follow the Getting Started Guide where you will find this suggestion on page 24:
"Print not correct size (G-Code)
Verify values for X,Y,Z by typing command M501. Values should be X119 Y119 Z2020 E100. If
for some reason values are not this, change with G-code command M92 X119. Save settings on
firmware with M500 command. Type M501 to verify change has been made."
If you're using Repetier-Host, you'll find a Gcode command line on the Print Panel where you can type the commands as specified in the Printrbot guide. Other software will also offer this functionality.
If you've corrected the values then you should print a test object of known dimension (there's a good one on thingiverse here: http://www.thingiverse.com/thing:4203) and measure the longest dimension in each axis with callipers. Take a note of the difference between the actual size and the expected size to see if it needs more adjustment.
If the difference is greater than 0.1mm then use the following calculation to adjust the X, Y and Z values:
(current steps per mm) * (expected dimension) / (actual dimension)
Example for X:
119 * 40 / 40.4 = 117.82
Use the command line to enter the new values, save them and verify that they are saved.
Example:
M92 X117.82 Y117.82 Z2020
M500
M501
Another test print will confirm if you've found the sweet-spot for your machine or, if you want to save on plastic, you can mark a reference point on the moving parts of your Printrbot and use manual control to measure the distance travelled.
Thanks to K1nc81d for a great answer on the Printrbot Answers pages: http://help.printrbot.com/Answers/View/34/Calibrating+based+on+a+test+print#answer358)
AntonioStatistics: Posted by Antonio — Thu Mar 13, 2014 5:08 pm
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