0.5mm-thin-wall - two perimeters at every layer?

Hi,

while calibrating my printer with Slic3r first using this calibration object - 0.5mm-thin-wall, I had a single loop at every layer. Now I'm switching to Skeinforge, using latest version 50, and every layer has two perimeter loops... Layer height 0.4mm, P/W ratio is 1.8, so double wall will be far too wide.

I've been playing more with SF50 settings, turned almost all the plugins and what I discovered is:
- layer height 0.4, edge width/height ratio 1.5 generates 1 loop correctly (SF calculated edge width - 0.6mm)
- layer height 0.4, edge/width 1.8 - has two walls (calculated edge width = 0.72)
- I've found out that there are two walls when calculated edge width is grater then 0.66.

I need edge width/height ratio=1.8, giving edge of 0.72mm, thus skeinforge generates two loops

Any ideas WHY ?

--
Adam

Edited 1 time(s). Last edit at 06/29/2012 08:00AM by acc.

If its the only problem, then just lower layer height....
Skeinforge slicer isnt too great with thin walls anyway :0(

I myself have another problem with 1-1.2mm wall and 1/2 of inside tracks are weird, coused bad quality result...

Hi

I am also facing the similar issue, not sure about SF version though, most likely its 48.

Layer height = 0.4 &
with 'edge w/h' = 1.8 (default), m/c is doing two walls total thickness ~ 1.45 to 1.5
with edge w/h = 1.5, m/c is doing single wall with thickness ~1.65 to 1.7

I am confuse shall we get the right thickness by changing the edge w/h or layer height. My confusion is due following lines in reprap-wiki calibration guide

[reprap.org]
Objective: to correct the layer height settings to reflect your printers actual layer height.
Calibration Object: 0.5mm-thin-wall.stl
Instructions
Print the 0.5mm thin wall cube and make sure that the layers adhere well but the nozzle does NOT drag through while printing.
Adjust softwares layer height in .01 increments until you get a nice print.
Depending on other factors you may find it hard to get all four walls to print nicely. For the first pass if you can get just one wall looking good then move on to the next test.

can some one tell us what is the right parameter to tune here w/h or layer height?

Thanks
-nilesh

I think following is the expected behavior. The purpose of w/h is the increase the width of perimeter for better bonding of first layer. Also the purpose of this calibration object in my opinion is to get the layer height right and hence we should only focus on the height of the thin wall getting right and not the thickness.

Layer height = 0.4 &
with 'edge w/h' = 1.8 (default), m/c is doing two walls total thickness ~ 1.45 to 1.5
with edge w/h = 1.5, m/c is doing single wall with thickness ~0.65 to 0.7 (in previous post this value was mentioned as 1.65 and 1.7 which was an error)