Cura Line Count Per Layer Not Matching Expected Value

[AgelessRevision 0]

Hello Everyone,

 

When printing out a basic rectangular prism of dimensions 35 mm x 12.0 mm x 4.2 mm ( x, y, z), @ 0.8 mm line width, laid in lines along the length of the part with 100% infill density, I expect the lineCount to be equal to: lineCount = (y_dim_length)/(line_width) = (12.0 mm) / (0.8 mm) = 15 lines. But for some reason I always get 1 line less than I expect. Here is a picture to illustrate more clearly. If you count the number of lines in that rectangle it comes out to 14. 

 

I am currently working with Cura 3.6 on an UMS5, although before I was working on a UM2+ extended and had the same issue. I imagine this problem is not related to the printer, but my inability to operate cura appropriately.  

 

I thought maybe there were some settings that somehow would make 14 0.8 mm lines flatten out to be 12.0 mm, and caliper measurements report  11.8 mm which isn't to bad I suppose. 

 

I also tried slightly making the y-dimension larger, for example changing the y-dim length from 12.0 mm to 12.2 mm and it indeed does slice 15 lines instead of 14, but the actual dimensions measured with a caliper increased to 12.5 mm.

 

Do you guys know what's going on here? My end goal is to have dimensionally accurate y-length of 12.0mm with 15 lines at 0.8 mm line widths. 

 

Much appreciated

 

[peggyb 171]

I tested your setup, Cura 4.0 beta: I disabled all wall, top and bottom, only infill (100%, lines, direction 90 degrees)

set the infill line width to 0.8 (0.8 nozzle) and counted 15 lines.

No idea what the measure is of the printed part, due to flattening of the plastic...

I think the best way to get your measurement is to play with the line with values.

 

Edited February 16, 2019 by peggyb

[AgelessRevision 0]

Thank you peggyb for your response. I see that you set line width to 0.75 and infill line width to 0.8. That's interesting, when I set line width to 0.75 and infill line width to 0.8 I get 15 lines also, like you have shown. With line width set to 0.75, and infill line width set to 0.8, do you think every line that is laid down will be about 0.8 mm? I'm not sure how infill line width differs from line width. 

 

Thanks again! 

[AgelessRevision 0]

Interesting, I was just messing around with some line settings as you have suggested and found that changing line width from 0.8 to 0.77 changed the number of sliced lines from 14 to 15. I did not observe any effects or visual changes in the lines from changing infill line width to even a small value of 0.2. What's even more interesting is that the horizontal expansion setting also changed the total number of sliced lines. I set line width and infill line width to 0.8 which originally produced 14 lines, but after changing horizontal expansion to 0.15, the line count increased to 15!