Odd wall thicknesses

[anthonyt 0]

 

I have these odd wall thicknesses (about 2.25mm and 1.75mm) on my plots where I need a consistent wall thickness of 2mm:

Here is the OpenSCAD code that I used for testing to produce the image above.

difference(){

 union(){

  cube([8,20,4]);

  translate([8,4,0])cube([4,12,4]);

 }

 translate([2,2,0])cube([4,16,4]);

 translate([6,6,0])cube([4,8,4]);

}

I am using the default profile in Cura 13.06.5.

My initial guess is a rounding issue in the slicer.

 

[illuminarti 18]

Have you actually looked at the coordinates in the gcode file? I just tried slicing this in Cura 13.06.5, with 0.4mm nozzle size, and 0.8mm wall thickness and it came out spot on.

I wonder if perhaps the problem you're seeing is due to head positioning inaccuracy, perhaps due to backlash, or some sort of alignment or pulley eccentricity issue?

 

[anthonyt 0]

It does not look like a gcode issue (I checked a layer using this website: http://gcode.ws/ ). I will examine the pulleys now.

 

[anthonyt 0]

I think I got it working now. The X-axis belt at the motor was fairly loose and could not be tightened without filing out the motor slots on the back board. It is printing those walls properly now!!

Obviously I started this topic in the wrong section.

 

[gr5 2,210]

The bottom layers, the first 1 or 2 mm tend to come out not as good - they tend to get what some people call "elephant's foot". The bottom most layer can't shrink because it's squished into the tape but each layer above that shrinks a little bit more until it eventually settles down. So I would print at least 3mm before measuring.

 

[anthonyt 0]

The bottom layers, the first 1 or 2 mm tend to come out not as good - they tend to get what some people call "elephant's foot". The bottom most layer can't shrink because it's squished into the tape but each layer above that shrinks a little bit more until it eventually settles down. So I would print at least 3mm before measuring.

 

In this case, it was not the squishing as one section was thinner than it should be. I had not expected the slop in the X motor belt to produce consistently measurable differences.

As I tightened that belt, those two dimensions started coming together. I just needed to file out the slots about 2mm longer so that the motor could be moved to properly the tighten that belt.

Anyway, I am very glad that it is working nicely.