Bed material

The bed material needs to satisfy two somewhat contradictory goals:

• The bed material must stick to the plastic coming out of the extruder. Otherwise the partially-printed part will slide around, then the next layer of the part won't be aligned, and you'll have a big mess.
• The bed material must not stick very strongly to the plastic coming out of the extruder. Otherwise you'll create perfectly-printed parts that are impossible to remove from the bed without damaging one or the other or both.

Some bed materials work better than others.

PLA and ABS are the most popular plastics for RepRaps to extrude; ABS seems much pickier about the surfaces it works on.

Experiments with ABS on various bed materials

ABS does not seem to stick to the MDF bed at all.

• Electrical tape - sticks, but not well enough to stop warping.

• Glass - doesn't stick at all.

• CD-Roms - sticks well, gives a nice surface finish, but tends to warp. Build area is obviously very limited (and circular!).

• Acrylic Sheet - works! ABS sticks to it quite nicely; I had some warping, but I only used 1.5 mm thick Acrylite FF P99 Acrylic Sheet from Cyro Industries. I've got some thicker stuff to test again as soon as I get my extruder running without the flexible drive.

• 1/4 inch Acrylic Sheet - works very well. Strong enough to resist warping. Rafts need to be somewhat weaker than the part, otherwise removing the part is very difficult.

Wade 2008.10.01

• Conductive foam (the kind that you use to ship IC chips I have found works very well and you can reuse it as long as your first layer is not deeply embedded.

Bruce W 2008.10.07

For HDPE, a good bed is a 'plastic' kitchen chopping board (probably itself made of HDPE). A raft, such as that produced by the skeinforge software, sticks to the bed, provides a base for the product and enables the product to be removed without damage to the bed.

Jon Wise 2008.11.14

• Blue (Painter's) Tape

A surprisingly awesome surface. Not enough to stop warping, but relatively cheap and very durable. Some brands even work on a heated bed, so long as you do not attempt to peel them off above room temp (don't try, it's icky).

• Kapton Tape

Another good surface, especially when used with a heated bed. Not so great on the pocketbook, but with proper handling a good investment.

Further reading

• Heated Bed mentions some materials used for heated beds, but focuses on things beneath the surface -- the heater, the insulation, and the control electronics.
• Frame material
• materials discusses all materials we've used so far in building RepRaps and RepStraps.
• is another place to discuss materials that won't melt when touching molten plastic.