Crusty first layer

I'm using Slic3r to create my gcode, and Pronterface as my host. Can anyone tell me which parameter I should adjust to eliminate the "crusty buildup" I get. It seems to only happen on the lower layers. I'm running ABS.. Print parameters as follows:

Accuracy:
Layer Height = .3
1st Layer height ratio = 1

Retraction:
Length = 1
Lift = .3
Speed = 30
Extra length on restart = 0
Min travel = 2

Print Settings:
Perimeters = 3
Solid layers = 3
Fill density = .4

Printer:
Nozzle dia. = .35

Filament:
Diameter = 2.8
Extrusion Mult. = 1
Temperature = 230
Bed =98C

Print Speed:
Perim. = 30
Small Perim. = 40
Infill = 45
Bridges = 60

Other:
Bottom layer speed ratio = .3

Thanks

It may be that you are trying to print ABS on blue tape. I have never heard of anyone doing that.

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I think you're base layer is just way too low.
It looks like the extra filament is rolling up.

^^That is exactly it. Too low of a first layer. Add some Z offset in Slic3r, try starting with 0.1mm.

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Agreed. Too low of a fist layer. I usually leave the thickness of a sheet of paper between my extruder and the bed.

In my setup there is a fine line between having the head low enough on the first layer so the print sticks and too low which causes this 'crustiness'.

How I would love to be able to print the first layer the same height as the rest....

I print PLAoin glass with the normal layer height and also ABS, but I need to use ABS juice to get ABS to stick to glass.

I wounder if printing a "brim" low and crusty but the rest of the first layer at the correct height would work? If you are able to hand modify gcode you could try it.

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[www.hydraraptor.blogspot.com]

If you don't have a heated. bed invest in one.
I spent months fighting to get first layers to stick, with a heated bed and either Kapton, or blue painters tape for PLA, I rarely have any difficulty.
I use a piece of printer paper to set Z 0 and just print with the layer height the same for the first layer.

I am hoping my problems are mainly due to material factors, I have noticed other people complaining about adherence problems due to cheap chinese filament and I suspect that is what I have (although sourced from Sweden).
I have been doing some testing recently and having some success by using clingfilm on the glass which although does not solve the problem does improve it considerably.
Re Nophead's idea of a "crusty brim", that probably would work if there was one item on the bed and it had a solid base, I find my main problems are the initial perimeters for small holes and shapes inside the main areas and the fact there may be multiple objects in which case a brim, crusty or not, will not help.

Edited 1 time(s). Last edit at 06/17/2012 05:05AM by glyn.

If it is just perimeters that are the problem, perhaps squish those but do the infill at the correct level to avoid the crustiness. I have done that in the distant past when I had adhesion problems.

Or just slice the first laver with a big W/H ratio. That squishes the filament without distorting the shape.

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[www.hydraraptor.blogspot.com]