Question on cutting PVC

[willmorgan]

So I have been cutting PVC for a while with no issues. I have the feeds and speeds that are needed, everything is good. Then a new customer comes in and wan't to start doing business with me but tells me the shop he use to use can cut 5 sheets per hour. I'm thinking wow, that's good.
So here is the issue, I let Aspire dictate how many passes to make considering the depth of cut. For his work, there are 24 pieces per sheet and using 3/8 PVC. The program tells me 2 passes.

My question is how big of a pass do you all take when cutting PVC, could you do it in one pass and speed it up?

Also I have a router and the highest speed is 21,000, how much faster could I cut the sheet if I had a spindle?


Thanks for you help,
Will

[Brady Watson]

My question would be if you want to be his employee cutting 40 sheets in an 8hr shift.

It is possible to cut it in a single pass if you have good hold down - but this completely depends on the design to be cut and the tolerance it needs to be cut to.

If you were to take this on, you would want a spindle to prevent it from bogging down (esp. if in one pass) and for longevity. That PC isn't going to last long in production. Buy a few extras...or spindle up.

-B

[willmorgan]

Thanks for the reply Brady
He only has about 40 sheets per month but I was trying to figure out pricing.

So a spindle is that much better? Do they fit on the shopbot I have pretty easy? I have the newest control box now. I guess I will really have to look into that.

[knight_toolworks]

it is easy to do in one pass if you are not using a 1/8" bit on 1/2" material. I use a climb cut and a 2f straight bit and it will stay in place.

[Alex Naumenko]

I can cut 1/2 pvc with one pass .375 edmill @ 250ipm. That is for something bigger than 1 sqft. Small stuff two pass smaller endmill.

[RossMosh]

PVC should be cut deeper and slower rather than faster and lighter passes. You'll have less of a chance of having edge issues this way. O flute is theoretically the right cutter but you shouldn't see much of a difference using a two flute bit. Just dial the rpm back or go faster with the two flute bit.

I have no idea what these panels look like so I'll speak in general terms. You can cut 3/8 PVC with one pass with a 1/8" bit if you're equipment is up for it. I did it yesterday. I'd recommend a minimum of a 3/16" bit and a 1/4" bit will be best.

To process PVC quickly and efficiently you need the following. A good hold down (read good vac setup), run a cutter with a width similar to the thickness, and a good dust collection setup. The biggest time waster with PVC is packing the kerf. It takes extra time to clean everything up and that will kill your production time. I find running 1/4" bits on 3/8" material with a spiral up bit you should have minimal cleanup after cutting. You should be around 2ipm for cutting, full depth pass, and probably around 15,000 rpm. You're going to want to stand watch and monitor the parts so they don't move at the end of the cut. If you go to a 3/16" bit, it will probably pack the kerf a bit to eliminate the part kicking but you'll have more cleanup.

[joe]

Wow Ross,

All good information from a Pro.

Joe

[willmorgan]

Thanks all, very good information!

[knight_toolworks]

unless I am cutting large pieces I always use a straight bit. then I can cut real small parts with no loss. I do a climb cut then the shavings stick to the scrap. I almost never lose a pvc part no matter how small.

[willmorgan]

Would one of you tell me why you use the climb cut instead of a conventional cut?

[knight_toolworks]

Would one of you tell me why you use the climb cut instead of a conventional cut?
it makes the shavings stick to the scrap so you don't have to clean them off.

[jerry_stanek]

I use the conventional cut as my pieces have a better edge. I just bought some 2.5 mm upcut bits and cut 5 sheets of 12mm today the chaff stays in the cut and no lifting. Much better quality cuts than I was getting with a straight bit. I am running them at 10000 RPM 2 IPS and .12 deep.

[Brady Watson]

There is no better advice that can be given to you than first hand experience. Buy a bit, go to a big box store and buy some solid white PVC trim boards and start cutting. It won't take long to find out what gives you the best edge in the least amount of time.

This is how most of us figured it out back when there wasn't anybody to ask.

-B

[joe]

That's right Brady!

Not sure if asking questions like "feeds and speeds" is ever as good as using your own equipment to work it out. Tests don't take all that long.

Joe

[knight_toolworks]

sometimes you have no clue where to start like with phenolic. wish I never started cutting that it is the worst thing I ever cut stinks my shop up and the whole basement causes the worst slop in the machine and it dulls bits in a hour and a half.

[joe]

Steve, You got me laughing. Once you have the product in your shop that's not the time to learn the ends and outs of a product. We've all done that.

Joe

[knight_toolworks]

Steve, You got me laughing. Once you have the product in your shop that's not the time to learn the ends and outs of a product. We've all done that.

Joe
I did a small test and it seemed ok. then the customer really gave it to me a month or two later he gave it to me upto 1" thick. and he keeps having it delivered. the 1" I had to shave off 1/16" as it was over thick that was the worst. then I found one piece warped and no way to hold it down. screws are not even strong enough. Plus the test did not show me it kills bits. you have to keep the rpms low like 6000 cutting 1 ips. this was absolutely critical. I was cutting it 1/4" in a pass and 2 passes and a cleanup on 1/2" material. but I wonder if I did 1/8" and cut twice the speed if it would be better? the bit has to stay cool as possible to get even a little life out of it. the fist time I did not know the bit was so dull it was still cutting but the shavings caught on fire in the cut.

[willmorgan]

Thanks all, I did do some testing and was really amazed at how fast and good the machine could cut. I would have never thought that. I really do appreciate all of the knowledge here and your willingness to help out. I hope soon to be able to contribute as you all do.

Will

[scottp55]

Thanks for phenolic tips Steve!
Have to cut some this next week.
Much appreciated as I only have the one piece.
scott