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PostPosted: Mon Nov 16, 2009 12:23 am 
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Brazilian Rosewood
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Anybody have an idea for a good spindle speed for plexiglass. I am using an 1/8 inch upcut spiral to .130 depth.

Thanks

Shane

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PostPosted: Mon Nov 16, 2009 10:59 am 
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Brazilian Rosewood
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Spindle speed and feed rate are always related, one requires the other.

Run at 64IPM per 10,000RPM of spindle speed. Use a cutter with at most two flutes, and you'll probably have to double up your finish passes if you have chips re-welding.

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PostPosted: Mon Nov 16, 2009 11:05 am 
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Koa
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http://www.amanatool.com/inplastic/index.htm
This doesn't answer your question, Shane, but ran across these the other day.
Looks like some cool tools for plastics.
Nelson


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PostPosted: Mon Nov 16, 2009 12:01 pm 
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Shane, Try an "O=flute" bit from Onsrud. These have worked the best for me on a variety of plastics. No issues with melting or welding.

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PostPosted: Mon Nov 16, 2009 12:39 pm 
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I hate plexiglass. It is a pain to cut.
Are you running coolant/lube?

Can you used polycarbonate - Lexan instead? It is so much easier to cut.

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PostPosted: Mon Nov 16, 2009 4:20 pm 
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Cocobolo
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Using a 2 flute carbide cutter, you should be at 13062 rpm @ 10.468 ipm. Your depth of cut is a bit much, at least break it in half, go .065 depth for 2 passes. Use a continous light blast of air to help cool down the work.


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PostPosted: Mon Nov 16, 2009 10:15 pm 
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Brazilian Rosewood
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arie wrote:
Using a 2 flute carbide cutter, you should be at 13062 rpm @ 10.468 ipm


Whatever program you're getting your feeds and speeds from is pulling your leg, Arie. At that sort of RPM the feed rate should be closer to 80IPM.

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PostPosted: Mon Nov 16, 2009 10:28 pm 
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Brazilian Rosewood
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It worked great at 20IPM at 16,000 RPM. But I only took about .040 per pass. The program ran an hour and half! But it turned out nice! I am just playing with gasket material now and hopefully this jig will be ready to go.

Thanks again everyone...more dumb questions to come!

Shane

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PostPosted: Mon Nov 16, 2009 11:08 pm 
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Brazilian Rosewood
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Gasket worked out well also (screen door rubber) and I am now good to go on running some radius dishes! I will post pics of the set-up once I have a dish done!

Shane

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PostPosted: Tue Nov 17, 2009 4:09 pm 
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Cocobolo
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Bob Garrish wrote:
arie wrote:
Using a 2 flute carbide cutter, you should be at 13062 rpm @ 10.468 ipm


Whatever program you're getting your feeds and speeds from is pulling your leg, Arie. At that sort of RPM the feed rate should be closer to 80IPM.



I chose moderate feeds and speeds, so feel free to explore. Either way the math is simple:

sfpm * 3.82/ cutter dia. = rpm
rpm * ipt * # of cutter teeth = fpm


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PostPosted: Fri Dec 04, 2009 8:47 am 
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Walnut
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Tim McKnight wrote:
Shane, Try an "O=flute" bit from Onsrud. These have worked the best for me on a variety of plastics. No issues with melting or welding.


This is an excellent suggestion!

I use Onsrud O-flutes for cutting everything from 1/2" to 1/8" plexi to Corian counter tops. The right tool for the job.

Another nice thing about using Onsrud tooling is they provide chip loads for all their tools. Make Feeds and speed very easy to dial in.


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