Bug in Sparse Infill - can anyone confirm?

[Rick Zehr]

I've been fighting an issue on a print for weeks, and have probably burned through around $150 of filament trying to get rid of an artifact by trying every setting and parameter I could vary, with no luck.

The issue is that on a 3/4" more-or-less tubular piece with 50% infill, i was getting a small glob at external periphery start-points, which stretched out into a "streak" 2-4mm long in the direction of travel. No change in retraction suck or prime, speed or acceleration, temperature, or anything else I could find seemed to change it significantly. Loops from Inside or Outside made little difference.

I finally (I think) pinned it down to an apparent bug in Stacked Sparse Infill. I was using Stacked Sparse Infill set to 1, i.e. do the infill every other layer. This is supposed to increase the flow rate to fill an n X layer-height infill layer every n layers. In other words, it would put down twice as much plastic every other layer.

So this morning, I tried Sparse Infill = 2, i.e. infill every third layer, presumably using 3 times as much plastic to fill.

Son ofd a B****!    The result was a much larger glob and streak at the periphery start on every third layer. So I set Sparse Infill to 0, and the globs at periphery start shrank away to almost nothing.

I construe that KS sets the higher flow rate for the Sparse Infill, but applies that higher flow rate to the whole layer; peripheries and all, which is obviously incorrect.

Can anyone confirm this as a bug, to support my conclusion? 

[toranarod]

Thank you for this great information.   

I must commend you on your perseverance.  Well done.  I to will give this a try 

great job. 

[toranarod]

Just tried it. I never would of thought of ever trying that, I was under the impression it was not related to the problem.Thanks 

Good job and good post. keep up the good work.

 

On Monday, 24 February 2014 06:39:18 UTC+11, Rick Zehr wrote: