[mactec54]

Well what material would you suggest? This is turning out to be a lot more difficult that I expected to get a little flat plenum. Maybe I could attach it to some sort of backing material like melamine to keep it straight?

You have to say what the material is in contact with, chemicals / water Etc. Delron / Acetal can be used in most cases, they all will bend when machined though

Phenolic sheet would be a good choice if you can use it, and it will not normally bend when machined

[tstanley01]

You have to say what the material is in contact with, chemicals / water Etc. Delron / Acetal can be used in most cases, they all will bend when machined though

Phenolic sheet would be a good choice if you can use it, and it will not normally bend when machined

Just air. It is setup on a cnc router.

[mactec54]

Just air. It is setup on a cnc router.

Then the Phenolic sheet would most likely stay flat the best, don't get the glass filled as this won't machine as well

[joeavaerage]

Hi,
I've had pretty good results with acrylic. It does not absorb moisture and remains flat after machining. It is very inclined to gum up tools
when its cutting, being very heat sensitive, so I use flood cooling, thereafter it cuts fine.

Acrylic is one of the cheapest plastics so you can afford to get a thick piece thereby avoiding distortion when cutting.

Acetal is my go to material for making parts, it cuts well, again with coolant, and remains dimensionally stable with minimal water adsorption.
PEEK is also good but both Acetal and PEEK are both quite pricey, great for small parts, for larger parts cost becomes an issue.

Craig

[mactec54]

Hi,
I've had pretty good results with acrylic. It does not absorb moisture and remains flat after machining. It is very inclined to gum up tools
when its cutting, being very heat sensitive, so I use flood cooling, thereafter it cuts fine.

Acrylic is one of the cheapest plastics so you can afford to get a thick piece thereby avoiding distortion when cutting.

Acetal is my go to material for making parts, it cuts well, again with coolant, and remains dimensionally stable with minimal water adsorption.
PEEK is also good but both Acetal and PEEK are both quite pricey, great for small parts, for larger parts cost becomes an issue.

Craig

Check the size of the sheet that he is using Acetal (Delrin) will not stay flat in a sheet that size and thickness he is using

If he is able to use the 3/4" 19mm thick it may stay flatter than the PP sheet but if it is 6mm thick it will be like a banana a sheet that size