Quick Help Needed; Advice on cutting UHMW

[kfitzgerald@graphicmetalsinc.com]

Just got a call from someone who wants some circles cut out of UHMW. He is coming at 3:45 today (about 2 hours from now).

Never cut UHMW on the ShopBot. Can anyone give me advice on rpm and feed speeds? The bits I have are a 1/4" Vortex up/down spiral, and a 1/4" straight two flute. Also have a 1/2" upcut. Which bit would be best? Thanks in advance.

Regards,

Kevin Fitz-Gerald
Project Manager

Graphic Metals, Inc.
P.O. Box 31
Bryan, OH 43506
Voice 419-636-5757
Fax 419-636-6404

kfitzgerald@graphicmetalsinc.com (mailto:kfitzgerald@graphicmetalsinc.com)

[papadaveinwy]

Kevin your 1/4' straight two flute should do the trick if you guys spring for a vortex cool tool it will help greatly. David in Wyoming

[graphicmetals]

Thanks David. I did use the 1/4" straight two flute at the second slowest speed on the router and a feed of 2 ips. It worked very well. No melting at all. It created little "pellets".

I am familiar with the Vortex brand, but what is a "cool tool"?

Looks like an ongoing project as the individual was impressed with the accuracy and quality, plus it is reducing his costs by 40%.

-Kevin

[papadaveinwy]

Kevin the cool tool is a device that you hook to your air compressor and without any moving parts drops the air temp down to as much as 100 degrees below that of the surounding air. great tool their web site is http://www.arizonavortex.com/cooltool.htm you clip it on to your bot with a magnet this keeps not only the plastics from melting but with all wood, corian, etc. increases the bit life David in Wyoming

[bjwat@comcast.net]

Wow! That cool tool sounds..err..Cool! LOL!

DO you have one of these David? I think I am going to need one of these for cutting out lexan. How much is it? I didn't see prices on there.

[papadaveinwy]

I think it's around $225.00 there is a priceing index somewere on there web I use to have one but alas in my move to Wyoming it seems to have gotten run over by a semi truck!!!!!!!!!! I am going to get anouther one. David in Wyoming

[sheldon@dingwallguitars.com]

This is a little off topic, but I just received my vortex gun in the mail today. It seems to work OK, I was expecting cooler temperatures and more output though. I estimate 1 or 2 cfm delivery at best. Does this sound right?

[gerald_d]

I am a little sceptical of this vortex cooler. Sheldon, does it really give off warm air from some point? If not, then it is really nothing more than a venturi blow gun. In other words, I wonder if a simple air nozzle is any worse than the "Vortex".....

[sheldon@dingwallguitars.com]

Hi Gerald,

Cold air exits one end and warm out the other. The surface of the tube gets very cold at one end and very warm on the other. I think the concept is valid.

My concern is the output, it seems pretty restricted. I'll buy a smaller diameter loc-line nozzle to see if that will at least increase the velocity.

[papadaveinwy]

Sheldon sounds a little light is this the one that was on e-bay?
Gerald these have been around for about 12 - 15 years the machineing industry was the first to use them not that brand but the same idea The one I had you could freeze your fingers if you left them in the way of the flow for an extented period of time. David in Wyoming

[papadaveinwy]

Sheldon if it is set right then you shouldn't be able to touch the "warm end" these temps are adjustable by the amount of flow going through and thereby from your compressor they do take alot of air. David in Wyoming

[waynelocke]

I just saw a HerSaf router bit for plastic at the Dallas CWW Woodworking show. The bit is at www.hersaf.com/cutters07.html. The bit is sold in sixes of 1/8" to 3/8" and is screwd to one of their spindles. The cutter is eccentric so it is not in total contac with the material and is supposed to run cooler and solve a lot of the heat related problems in plastic. They cost about $50 but they may be worth a try.
Wayne Locke