Slic3r bridge speed warning
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I posted this on the RepRap forums but just thought I'd mention here too. Whilst taking a break from some other issues, I decided to play around with bridge speed. I set it really high on the basis that stretching the filament quickly might lesson the tendency to sag. I forgot to put it back when I printed my next object which was a 100mm x 100mm x 3mm thick cube (no bridges needed). It seems that slic3r uses bridge speed for the first top solid layer after the infill layers and not the solid infill speed that one might expect. I suppose this is technically correct as the lower infill layer will have voids which need to be bridged.
It was exciting watching the the print head trying to print solid infill at 150mm/sec but not so good when I realised that a Diamond hot end cannot melt filament that quickly. I'll give the Titan extruders their due though - they tried their best to shove the filament through.
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Good tip. Yeah I think its easy to forget the first layer of top infill is considered a bridge by Slic3r. Even if your infill below is 90%. There might be room to optimise slic3r's algorithms to only consider that a bridge if the infill underneath is below a certain density. They might be doing that now, I was lurking in Slic3r github repository looking for answer to what xy compensation actually does. Still none the wiser.
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Just to clarify for anyone else. Slic3r has 3 speeds for infill under "Print Settings". There is "Infill" (speed for printing internal infill), there is "Solid infill" (Speed for printing solid regions - Top/Bottom/Internal horizontal shells), and there is "Top Solid Infill" (Speed for printing uppermost external layers).
The first layer of solid infill uses none of the above - it uses Bridge speed.
