questions on printing objects..

hey guys, my printer finally prints! however, when i try to print a belt clamp (as an example) my first layer doesnt want to stick (pla/yellow masking tape). my questions are when do i need to use a raft? when dont i need to use a raft? is there a better build surface for me to use? do i need a raft on that? thanks

I have never used a raft and print on blue tape in PLA. ( no heated bed )

I have the first layer 5c hotter than the rest.

Be sure to purge the extruder before printing. ( I purge 40mm = G1 E40 F300 )

And when my bed was uneven I found it helped to have the flow rate modifier in Raft set to 1.05 ( 5% extra on the first layer )

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Yeah my first layer is set to 230C, while the rest are 185C. (call me crazy.. but it sticks very well).

im using ABS on Blue masking tape.

i run my entire print at 252C, just print slower and set the flow rate different for the first layer. I set the flow rate in raft to match the feed rate at .5. This is for perimeter and infill. i set the layers for rafts to 0 so no raft goes down.

Edited 1 time(s). Last edit at 08/12/2011 08:41PM by jamesdanielv.

When printing on blue painters masking tape, use a piece of sand paper to lightly scratch the surface and then clean it with some Isopropyl alcohol (Sold often as tape head cleaner) and don't touch it after you have cleaned it. Natural oil from your hands will reduce the bonding.
I think some blue painters masking tape has a film material that needs removing. The stuff I use feels a bit oily.
I had issues before I started using this method. I use a heated bed to reduce waping but not for bonding.

Also have the extruder tip very close to the print table surface. Basically squashes the PLA onto the tape for the first layer.
Temperature needs to be at 190C, depending on your heater/extruder/sensor you may not be getting the correct temperature that you may think you have.

I've been using foam core board, this kind you find in the office supply store, on PLA. if you adjust the depth just right it sticks, yet you can pull the piece right up after the print.

RepRot Wrote:
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> When printing on blue painters masking tape, use a
> piece of sand paper to lightly scratch the surface
> and then clean it with some Isopropyl alcohol
> (Sold often as tape head cleaner) and don't touch
> it after you have cleaned it. Natural oil from
> your hands will reduce the bonding.
> I think some blue painters masking tape has a film
> material that needs removing. The stuff I use
> feels a bit oily.
> I had issues before I started using this method. I
> use a heated bed to reduce waping but not for
> bonding.

Alcohol works really well but I find it makes for a one use build surface. But because I can never get the part off with out taking half the tape with it I only use it before printing large objects that are prone to warping.

The rest of the time I use plain old blue tape over and over.

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FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver