Dimension accuracy problem while printing with TAZ

General LulzBot TAZ
1

Hi,

I have been doing several tests with the new Lulzbot TAZ and I am having problems with dimensions both in xy plane as well as the z-axis. I have tried printing a 20mm x 20mm cube with through holes and I have tried printing 10mm x 10mm cube without any holes.

Both cubes have problems in terms of accurate dimension in all the three axis. I have checked the exported stl file and that is accurate.

There two kinds of problems we are facing:

  1. With the 20mm x 20mm cube with holes, there is dimension error in xy plane and even more in the z-axis. See attached photos.
  2. With the 10mm x 10mm cube without holes, there is dimension error in all the three axis and a substantial tapper with the lower layers being wider than the higher one. See attached photos.
  3. I have also attached photos of a part (Spiral cam) that we are using in one of our projects that show the difference I am talking about. You can see the 3D-printed part side by side with waterjet cut part.

We are an architecture and engineering firm and the dimensional accuracy in all the three axis along with the inner dimensions of the holes within a part, is really important to us. If we cannot achieve this, the 3D-printed part will be of no use.

Please suggest what you think we should be doing to correct the dimensional inaccuracy.

I have also attached the ‘gcode’ along with the ‘slic3r ini file’ of the configuration for your reference.

Looking forward to hearing from you.

Regards,
Shivang
Cube_20x20x20_Export1.STL (60.2 KB)
Cube_20x20x20.gcode (6.62 KB)

SpiralCam.jpg
SpiralCam.jpg1650×1404 597 KB

Cube_10x10.jpg
Cube_10x10.jpg1650×742 425 KB

Cube_20x20.jpg
Cube_20x20.jpg1485×1650 551 KB

2

I hate to say this, but how much did you investigate the current 3D printing technology before you invested in one?

All but the ‘Spiral cam’ seems within what I would expect. For that, I would think you have the first layer set very low - which is actually a good thing for making things stick to the bed. But obviously it reduces the height of your print.
Also, does the layer height divide evenly into the height of the object? If not then it could miss off the top layer because that would make it too tall. Try choosing a different layer height.

There are ways to improve calibration, have a read of these guides:
https://github.com/alexrj/Slic3r/wiki/Calibration
http://richrap.blogspot.com/2012/01/slic3r-is-nicer-part-1-settings-and.html

Good luck,
Antony

3

The taper in the cube could be mitigated if it wasn’t hollow. I suggest infill to give it better structure. (Also, if you happen to be using hairspray: don’t as it can cause parts to do that too.)