cutting thin materials and holding them down.

[Steve knight]

I have been cutting a lot of thin materials lately and I thought I would share some of the ways I found to deal with it.
The biggest problems with thin materials is that the vacuum does not really help when they want to lift up.
when I am talking thin I am thing maybe 3/16" and under. the thinner it is the worse the lift up problem. I really had to struggle till I got the hang of it with some .03 plastic.
a downcut bit would help but for plastics they cause the shavings to stick to the edge badly. but for thin woods it is a good choice.
so I am finding for the thinner plastics a 1/8" straight bit works pretty well. it leaves some shavings stuck to the edges but that keeps the part in place. so that lets you get more parts per sheet. you only need a small amount of uncut plastic between parts and they will hold in place.
cut speeds vary with materials of course. I found you can't cut 1/8" acrylic faster then about 60 ipm or the bit will break if your doing a single pass. but I have cut sintra and such faster.
but since changing over to the straight bits I have hardly lost any parts even when cutting a few hundred parts on a sheet like the picture below.
the time saved not having to glue down acrylic is really paying for it's self. you do waste a bit of material to get the spacing but it pays for no lost parts and no prep work.
I have not compared cut quality but it seems ok.
I found even trying to use two passes to cut thin material with a upcut can lift the material off the table on the first pass. Once that happens shavings get under the part and it won't lay back down.
so far I have been cutting at 8k and that seems fine.

[Michael Schwartz]

Thanks for sharing that. I wish I had known about this a while back when I was cutting some thin acrylic.

[Hennie Helberg]

You can also use double sided box tape to hold those small pieces in place while you are cutting

[Steve knight]

You can also use double sided box tape to hold those small pieces in place while you are cutting

thats a pain and sometiems not strong enough. I find it works better to sue the shavings to hold the part in place. plus try to take a whole sheet down.

[Scott Shepherd]

I find it works better to sue the shavings to hold the part in place.

Legal action against them to make them hold the part in place? Did you try asking them nicely first?

[Guy Mathews]

You can also use double sided box tape to hold those small pieces in place while you are cutting

I have tried both double stick tape and 3M Spray adhesive. Both worked equally well for hold down however the tape is easier to remove from the pieces and the spoil board. For this brass I used the spray and then cleaned the parts with WD-40.

Guy