SO3, Super-PID's and "plastics"

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SO3, Super-PID's and "plastics"

Postby kayaker » Wed Jun 10, 2015 5:14 pm

Anyone with their SO3 up and running using a Super-PID or other style speed controller on their trim router? I am interested to know if the lower speeds (more in line with typical speed and feed calculations) are getting results with noticeable reductions in melting on the tooling and cleaner edges when machining acrylic, lexon, etc.? I have the issue with my drill press as it runs at a high rpm, but not so much so on my Grizzly G0619 that tops out at ~ 1,700 rpm. I know the problems with melting should be reduced significantly when you can run at router speeds well below the base 16,000 rpm of a Dewalt 611, but I'm interested in people's experiences.
Take Care,

Jim. . .
--------------------------------------------------------------------------------------------
In the immortal words of Dr. Johnny Fever; "when everybody is out to get you, paranoid is just good thinking!"
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Re: SO3, Super-PID's and "plastics"

Postby JeromyReno » Wed Jun 10, 2015 10:33 pm

i ordered one but haven't gotten it just yet. i plan on cutting a lot of hdpe with my S3 but was pretty worried about the router melting it. i am setting up a micro drop lubricant spray system on it for cutting aluminum and im looking forward to trying to run super high feed rates with it on plastic also. i guess we will just have to see when it all comes together.
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Re: SO3, Super-PID's and "plastics"

Postby madhatter » Thu Jun 11, 2015 4:08 am

I have a SuperPID on my Dewalt DW611. I have cut cast acrylic and King Starboard branded HDPE.

** Disclaimer ** This is all new to me, so I am telling you what I have done, not whether it is correct.

I have cut cast acrylic using single flute 0.063 and 0.125 carbide bits (maybe a 0.25 single flute bit as well, I can't remember) at:
~15,000 RPM
0.05" Step
20-25 IPM for both sized bits.

The bits cut great, and the finish is clean. I have used some 0.031 two flute bits as well,(using an 0.030" or 0.040" step) and they work great as well. I can't remember the feed rate,(probably in the 20 IPM range) but most of what I run is in the 15K-18K RPM.


I have cut HDPE using single flute 0.063, 0.125 and 0.25 carbide bits at:
~15,000 RPM
0.05" Step
20-30 IPM for all bits.

Man, I love cutting HDPE. Clean cuts, nice chips that looks like rice. My 10 y/o son came in when I was cutting it and asked why there was rice all over. It was funny. Anyway, HDPE is awesome to cut, and while I am not sure of the "optimum" settings, it cuts fine with single flute carbide bits.

I tried cutting the extruded acrylic, and man, all of the scary campfire stories are true - that stuff just does not like fast spinning bits. I tried running my Dewalt as low as 5K RPM and it still melted almost instantly and gummed up the bits. I wasted three bits trying to engrave that devil-spawn plastic sheet. It was interesting from a "properties of materials" standpoint in that as soon as the bit hit the plastic, it melted and began building up a clear melted sphere on the bit right at the surface of the plastic, and the further along it went, the larger the melted plastic sphere became. After going ~10" across the surface, the bit was no longer even cutting the plastic (the Z-step was -0.05") it was just pushing it down and making a shallow canal from the melted plastic ball (see "friction-stick welding" for cool videos related to this). This was because I was holding the piece with double sided tape which has some give.
SO3 #0054
DWP611 - SuperPID
Prusa i3 MkII
SolidWorks 2015
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Re: SO3, Super-PID's and "plastics"

Postby kayaker » Fri Jun 12, 2015 4:17 pm

madhatter wrote:I have a SuperPID on my Dewalt DW611. I have cut cast acrylic and King Starboard branded HDPE.

** Disclaimer ** This is all new to me, so I am telling you what I have done, not whether it is correct.

I have cut cast acrylic using single flute 0.063 and 0.125 carbide bits (maybe a 0.25 single flute bit as well, I can't remember) at:
~15,000 RPM
0.05" Step
20-25 IPM for both sized bits.

The bits cut great, and the finish is clean. I have used some 0.031 two flute bits as well,(using an 0.030" or 0.040" step) and they work great as well. I can't remember the feed rate,(probably in the 20 IPM range) but most of what I run is in the 15K-18K RPM.


I have cut HDPE using single flute 0.063, 0.125 and 0.25 carbide bits at:
~15,000 RPM
0.05" Step
20-30 IPM for all bits.

Man, I love cutting HDPE. Clean cuts, nice chips that looks like rice. My 10 y/o son came in when I was cutting it and asked why there was rice all over. It was funny. Anyway, HDPE is awesome to cut, and while I am not sure of the "optimum" settings, it cuts fine with single flute carbide bits.

I tried cutting the extruded acrylic, and man, all of the scary campfire stories are true - that stuff just does not like fast spinning bits. I tried running my Dewalt as low as 5K RPM and it still melted almost instantly and gummed up the bits. I wasted three bits trying to engrave that devil-spawn plastic sheet. It was interesting from a "properties of materials" standpoint in that as soon as the bit hit the plastic, it melted and began building up a clear melted sphere on the bit right at the surface of the plastic, and the further along it went, the larger the melted plastic sphere became. After going ~10" across the surface, the bit was no longer even cutting the plastic (the Z-step was -0.05") it was just pushing it down and making a shallow canal from the melted plastic ball (see "friction-stick welding" for cool videos related to this). This was because I was holding the piece with double sided tape which has some give.


Yes, from everything I read, extruded acrylic is not a very machinable friendly animal. They say cast acrylic is OK to work with though. I made a couple 6" diameter lids with the drill press for a vacuum pot application and I'm guess it was extruded because as you were saying, it melted immediately with the various bits (and circle cutter) I was using. It was a pain cleaning up the edges so it would make a good seal. The speeds and feeds calculator I use would put a single flute 1/4" carbide bit (with, say, 1,100 sfm & .003" chip load) at ~ 50 ipm. Much faster as the bit size decreases. When my SO3 arrives, I am definitely going to experiment a bit with extruded acrylic to see if there is a sweet spot I can find. I have machined delrin and it was very nice to work with. Very clean cuts.
Take Care,

Jim. . .
--------------------------------------------------------------------------------------------
In the immortal words of Dr. Johnny Fever; "when everybody is out to get you, paranoid is just good thinking!"
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