Question Milling Foam PVC (e.g. Foamex, Sintra)

Hi,

Looking to mill foam PVC (trading names Palight, Foamex, Foamalux, Sintra etc). I have attached the recommended milling conditions from three manufacturers but having difficulty transferring this info for the V-Carve setting. For example, if I'm correct, the recommended feed rate would be 45mm/sec which I believe is reaching the extent of the stepcraft speed and 3000fpm is crazy rpm for a 3mm cutter. Some help calculating initial rpm and feed rate would be great and any advice on this material. Thanks.

Evan wrote: For example, if I'm correct, the recommended feed rate would be 45mm/sec ...

Without diving to deep into this topic - we are talking about: Feed rate 8" - 20"/min ?
If yes - I assume we are closer to 3,39 mm/sec - 8,47 mm/sec. What do you think?

Edit: and ...
3000fpm = 15.24 m/s or 15240 mm/s

Hi Worldhusky,

I know I'm new but I'm not beyond converting units well I hope so.

Its the combination of feed and speed that gives me a good cut, correct me if I'm wrong, slow feed with a high rpm results in excessive heat and low rpm with high feed may result in breakages.

Where I have a feed rate of say 10in/min or 4.2mm/s, it is the recommended cutting speed of 3000fpm that has me confused. From what I can see converting a 3000fpm cutting speed to rpm results in roughly 97000 rpm for a 3mm cutter.

www.engineersedge.com/manufacturing/cutting-speeds-feeds.htm

Can't see the wood for the trees so a second set of eyes would be great.

Done a bit more research on this, searching for info on Sintra yields more info, seems Sintra is the main trade name in the US. I found a good reference point from which to start based on info from this webpage.

www.camheads.org/archive/index.php/t-914.html

onsrud 1/16" upspiral @ 18000-19000rpm 80ipm
or 1/8" upspiral onsrud @ 15000rpm 90ipm
or 3/16" upspiral @ 18000rpm 135ipm

From what I can tell, taking from a few sites, you can run pretty fast feed rates because the material doesn't
really chip or else the chips are really really fine. Going to give it a go.

Other reference sites:
forum.vectric.com/viewtopic.php?f=2&t=18284
www.signs101.com/forums/archive/index.php/t-112369.html

Cut out a few parts today, very pleased with how it turned out. Ran the cycle with 16,500rpm (4 on Kress) @ 8 mm/s using a 3mm downcut in 1.2mm depth/step. Might experiment next time with 10 mm/s and little faster on the plunge rate.

Using the foam PVC to make an insert for an Ikea Ribba shadow box. Just need to remove the film and glue in place