CNC tabletop surface that is not wood, or MDF

[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey Jace,

@makerjace

If you use HDPE, I highly recommend a stress relived variant. Otherwise, the stock can warp (think potato chip) after facing the first side.

Thanks for the advice. I have asked the supplier about stress relief. They answered that their sheets are generally stress-free and have no tendency to deform. If I mill away 1 mm, it should not warp. They added, it is however important to note that as with all plastics, certain factors should be taken into account, such as cutting speed, tool quality and condition, and the specific conditions of the machining operation. Professional machining and the use of appropriate tooling can help minimize unwanted deformation.

Also @jarrfarr, who is the one with the HDPE wasteboard linked above, wrote that even after hammering in a T-nut every two inches (50 mm), a 3/4" sheet (19 mm) did not warp:

@jarrfarr

there is no flex whatsoever. The T-nuts are 2" apart and the holes are only 1/4" in diameter, We used a 3/4" sheet, secured with 6 bolts through the bottom of our table, so it’s pretty solid. The T-nuts bit in nicely to the HDPE.

I would however rather use HDPE slats with extruded aluminium T-slots between them, and fix the steel vises used to hold metal workpieces with these T-slots.