Plastics cutting

[joa]

I found a great resource article for all interested in machining plastics. In a nutshell it reaffirms what folks on this list have said...

http://www.plasticsmachining.com/199702/cnctooling.html

HTH,

Joa

[billp]

Komatex experience anyone? I have just done some test cuts in a sheet of thin ( 3MM) Komatex pvc/foam . The stuff cut beautifully with a straight bit, but I found that if I try to run a full length "tab"the way I do on model/boat kits, it is difficult to cut the sliver of pvc with a razor knife. It is not that it is difficult to cut, but it takes up a LOT of time in "cleanup" of that part. I then cut some pieces all the way through, and they machined perfectly, with only a dusting of 'fuzz'on the edges, and that easily wiped away.My question here is, are there any alternatives to this brand of foam/pvc board? the sheet I got cost about 22 bucks from a sign distributor, are there comparable products, or options in this area? I like the material, and hope to figure some way to get more practice with similar stuff...Thanks

[jgraphic]

Bill,

Sintra is another name for the same product. It would be available for a major plastics distributor or at a large sign supply house.

Jerry Hewett

[danhamm@abccom.bc.ca]

Sintra, I use it a lot..I laser cut letters for
the sign people..I get it from..Cadillac plastics
1-800-cpg-1000 or www.cadilllacplastic.com
they have a very good catalogue..Dan H

[mcw]

I am looking for a source of Sintra in the Oregon area myself. I have contacted Laird Plastics via email and am waiting to hear from them. They are located in a lot of states. I have asked for some samples to play with cutting lettering with.

http://www.lairdplastics.com/

[jim woods]

I have cut up to 1/2" Sintra letters on my ShopBot
using double stick tape for hold down. The tape to use is Permacell # P-02,you can get it from the K.R. Anderson co.

[EmpY]

Komatex, Sintra, Trovicel (which I think is now called Versacel), and Intecel are all brands of PVC plastics.

I haven't routed any yet (getting my ShopBot in a couple weeks!) but I have worked with it a lot in sign making. The 3mm thickness can be scored and snapped if you didn't want to use a saw. 3mm thickness will become brittle and easily shatter in very cold temperatures.

It does scratch easily.
It produces lots of static electricity when handling and moving it around. It attracts dust like crazy. It expands and contracts from heat/cold. The colors are not UV safe and will fade - some brands of PVC fade more rapidly than others outdoors. Komatex comes in at least 13 colors.

It's available slightly satin finish (KomaTEX as in TEXtured) as well as smooth almost glossy finish. Some brands smell almost like skunks when cut.

It probably never biodegrades - or at least not in our lifetime or our childrens lifetime, but that's just a guess.

Most enamel and latex paint do not bond well to PVC, and will scratch off easily. Vinyl screen printing inks, self adhesive sign vinyl, some water based acrylic paints like Dekka and Createx, and Krylon spray paint all bond to PVC.

[srwtlc]

I had a customer ask about cutting some plastics the other day, and I would like to know if anyone is cutting polypropelene and polyethelene. What bits, feeds, and speeds are best. From what I understand it would be bascically slotting of parts. Just looking for a little foreknowledge.

Thanks,

Scott

[donchandler]

Scott,
HDPE, PP, Teflon, PVC, etc are the main materials that I use. HDPE cuts nice, I have cut it up to 4" thick. A endmill for aluminum cuts it like butter.Travel as fast as you can without loosing steps PP is tougher to cut clean. Slow the router down and cut at about 1"/sec. Milled 844 3/4" holes in 3/4" sheet today with a 1/4"carbide up spiral bit. router was at 20,000 and the speed was .8"/sec.