How are you cutting HDPE?

[EricSchimel]

I've been cutting a lot of HDPE lately. Right now I'm cutting 1/2 HDPE at 2.5 inches per second at 18000 rpm taking about . 1" per pass. I'm using a single flute 1/4" up spiral but from Onsrud and I'm getting really good results.

I've been slowly upping my speed but I feel like where I'm at is really good.

How are others cutting? Are you going faster? Deeper per pass?

[Kyle Stapleton]

I have cut some before not sure what what the rpms were but I was cutting 4 ips .25" per pass with a two flit up cut.
Will be cutting four sheets this week and was planing on slowing it up a little and going .375 per pass.
This is the same stuff they make kids play ground equipment out of and no one is making any money at an 1/8" A pass. Find a scrap and try deep and fast till she snaps, that is what we will be doing this week.;)

[gundog]

I cut a fair amount of 1/2" Seaboard and Starboard same product different manufacturer. This is marine HDPE I cut it with a single flute Onsrud bit made for soft plastic 63-725 I cut one diameter deep 102 IPM or 1.7 IPS 18000 RPM. I have cut it in a single pass but the edge was not as nice. I have tried faster and slower and this has been the best for me.

Mike

[guitarwes]

Never cut any HDPE but I do cut a good bit of UHMW-PE. I use 2.6"/sec with a .5" depth at 254.7Hz with a .25" single O-flute Onsrud using a conventional cut. I have a 3HP spindle.

[Kyle Stapleton]

Here are my tests, never snapped a bit but got close.
2 flute up cut CMT
3ips
3 passes conventional
1st @ .33 2nd @ .66 3rd .77 using last pass offset of .01
rpms
1200
1400
15002929929300293012929829302

[gundog]

I just finished these tables up today they are all made from 1/2" Starboard Marine HDPE.
Mike

http://img.photobucket.com/albums/v292/millnut/20161115_135851.jpg (http://smg.photobucket.com/user/millnut/media/20161115_135851.jpg.html)

http://img.photobucket.com/albums/v292/millnut/20161115_135902.jpg (http://smg.photobucket.com/user/millnut/media/20161115_135902.jpg.html)

[EricSchimel]

Those tables look great!

Sounds like we're using the same bits and cutting at nearly the same speed. I've pushed my speed up to 2.5 IPS with . 1" passes and had great results.

[gundog]

I have been cutting this stuff for about 8 years now and tried many different strategies. The recommended chip load from Onsrud did not give me a good edge finish that could be a result of my vacuum hold down. I use a couple Lighthouse vacuum motors I don't know. I have cut the stuff with a Shopbot and my current machine the best edge finish I get is to back off the feed and not get as fast as Onsrud recommends. With my milling machine I can run those chip loads they recommend. I think it is a combination of rigidity of the machine and hold down, on the mill I hold things in a vise.

Mike

[gundog]

Finished these transom sink lids for a boat manufacturer I make their plastic OEM hatches.

http://img.photobucket.com/albums/v292/millnut/20161116_112634.jpg (http://smg.photobucket.com/user/millnut/media/20161116_112634.jpg.html)

[blackhawk]

I use the Onsrud 63-775 at 2.2 IPS, 16,000 rpm and usually cut no deeper than .25" per pass.

Mike's parts look really good, so I may turn down my IPS.

Mike - You mention that you use the 63-725 but that is for hard plastic. 63-775 is for soft plastic like HDPE. Was that a typo?

[gundog]

I use the Onsrud 63-775 at 2.2 IPS, 16,000 rpm and usually cut no deeper than .25" per pass.

Mike's parts look really good, so I may turn down my IPS.

Mike - You mention that you use the 63-725 but that is for hard plastic. 63-775 is for soft plastic like HDPE. Was that a typo?

I am pretty sure I took that number off the box but I could be wrong I will look tomorrow I think I bought the last ones off ebay from Zoro Tools. I usually buy tool bits one time a year and order a bunch. I know I ordered some for aluminum too so maybe that one was for aluminum now you have me wondering. I use the 52-700 series double flute for pockets when I want a good bottom finish.