Printed object is smaller
January 14, 2016 02:32AM
I have trouble with printed object it is 1,5 mm smaller than it is maded in DesignSpark Mechanical.
I have exported it as STL and printed and get smaller for 1,5 mm.
Why is that happends and what I should do?
I print it with repetier host and using PLA.
Re: Printed object is smaller
January 14, 2016 02:34AM
You have to adjust your steps/unit settings.
Tell us more about your printer and firmware you're using, for more help.
Re: Printed object is smaller
January 14, 2016 08:44PM
Yes - it is a matter of your printer calibration. Most software is actually unitless. You might enter units, but basically they mean nothing until you try to get a physical version of that object. The printer needs to be told how many steps are necessary to produce a millimeter of movement not only for the X, Y, and Z axes, but also for the E axis - you need to know that filament is being extruded at the proper rate.

X, Y, and Z calibration is usually formulaic - based on gear teeth, pulley tooth count, lead screw pitch, etc. The filament calibration is a more experimental process, but the techniques are well documented.

Let us know more about your printer and we can help you.
Re: Printed object is smaller
January 21, 2016 11:12PM
Hi, I posted somewhere else as well, but it seams that this is the right place to post my question.

I am new to this forum so if this is not the right place to ask my question let me know where to go instead.

I upgraded my printer bed to something more robust. It works very well as far as holding leveling without having to worry about it once set. The bed slides on bearing wheels on v-grouve slots on 1" extruded aluminum square blocks. The motion is done with a T2 belt, a GT2 20 teeth Pulley, a Nema 17, 1.8 degrees, and a bearing pulley attached on the other end of the belt so that it can roll. It all works great and I can print pretty well up to 0.06 layer thickness. The problem that I am having is that my print dimensions are not consistent and off from the drawn dimensions depending on the direction of the axis.

So after designing 4 intersecting rotating axis lines every 45 degrees (0,45,90,135, 180, 225, 270, 315, 360) I printed a structure 10mm tall, and 2mm thick. Measuring the thickness on each arm, showed that depending the position of the leg on the print, the measurements were from 1.86mm to 2.21mm. The designed dimensions were supposed to be 2.0 mm.

Here is a video of what I printed with some of the mesurments. You should get the idea.

So I know that something needs to be calibrated in the X and Y axis. You should know that I changed diameter of the rolling belt bearing from 22mm diameter to 15mm diameter. I had no choice as the new setup did not allow for using the same pulley diameter bearing. So I have a suspision that I have to adjust for the smaller radius somewhere in the Marlin firmware. I feel comfortable changing parameters in the Marlin environment, I just do not know where to look for this type of info.

Can anyone point me to the right direction with this?

Thank you

Edited 1 time(s). Last edit at 01/21/2016 11:16PM by Pianori.
open | download - 20160121_210945.jpg (228.5 KB)
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