3/4' plywood

[Ryan Patterson]

I am looking on suggestions on what feed and speed to use on ¾” plywood. I have been cutting the sheets with 3/8” spiral upcut and have tried up/down with 17000Rpm and 5ips. The problem I am having is the bits do not seem to last. For the first 10 sheets I get good cut on the edge then the cut starts to leave fuss on the edge. I have also tried 14000Rpm and get a little more life out of the bit. I cut 30 to 50 sheets a day and bits are getting expensive.

[bob_lofthouse]

Hi Ryan,

I've had exactly the same problem.

After alot of trial and error I now use a solid carbide 1/4" up and down cut spiral.

5ips on 3/4" ply.

6ips on 3/8" + 1/2" ply.

8ips on 1/4" ply.

This may be a silly thing to say but see if your direction is set to climb mill or convetional..... Our quality improved ten fold when we changed to conventional cut.

yours Bob

[Ryan Patterson]

Robert
thank you, At what RPM are you using. I am using a climb cut with the upcut bit and a conventional cut with the up/down. The reason for this is flex.
Ryan

[bob_lofthouse]

Hi Ryan,

We are running @ 18,000 RPM.

I tried an upcut bit once, but watched in amazement as it picked up a 8 x 4 sheep of 3/8 ply.

[elcruisr]

Ryan,
a big question is what kind of 3/4" ply are you cutting. I cut 3/4" sheets by the hundreds and tool life will vary widely by just what it is.
We do most of our cutting with a single flute 3/8" compression spiral, conventional cut. 17,000 to 18,000 rpm and 8 to 10 inches/sec. In elliotis (brazilian pine) or domestic with aspen or poplar core ply that tool will run 35 to 50 sheets of 20 to 40 parts each. If it's chinese you're going to eat up tools like mad. I have told one shop that I cut for that chinese core is out unless they're prepared to eat all that tooling cost. I even had one sheet of chinese on the last run that had a foreign object tear a chip out of the cutter and start a fire by the time we stopped the file! Cheap ply isn't always cheap at the end of the day.

Eric

[bob_lofthouse]

I find nails in my ply all the time..... and Sparks do fly...

We try to balance tool life against the cost of the wood and also how the wood looks.

[Ryan Patterson]

Eric
I have tried several plywood and found poplar core to cut the best. I plan on using a different supplier It might be the problem , I have had a lot of issues with delaminating of the plywood. Eric what size spindle do you have?

Ryan

[elcruisr]

We run a 5 hp Colombo. Have you tried different brands of tooling? Are you calculating chip load and seeing if it is within the tool manufacturers specs? Turning too many RPMs for a given feed speed will dull a tool prematurely. This is when I get hold of a tech rep from my tool manufacturer and ask questions. If they don't give good answers try a new supplier.

Eric

[elcruisr]

One more thing, if that is chinese poplar core, and I suspect it might be if you are having delam problems, it is not a true poplar species but something from asia that eats carbide for lunch. Chinese poplar core has been the subject of troubles on several commercial woodworking forums. It eats saw blades and CNC tooling, warps and delams at an amazing rate. Everyone I know that has tried it in the CNC business has dropped it like the proverbial hot potatoe.

Eric

[Ryan Patterson]

Eric,
I am getting it from Dixie plywood I think they are a supplier for you to. I am using their preFinsihed maple ply I has Colombia stamped on the edge. I think we are close enough to have the same vendors who would you suggest getting prefinished plywood from.

[elcruisr]

I've been having some fairly bad luck with the prefinished stuff lately, it seems like it's all chinese that's available locally. I've been using the stuff from McEwan when I need it but that's because I get a better price from them. Which companies tooling are you using?

Eric

[bleeth]

If you get deliveries from Whittelsey (in Miami) you might try their prefin.-It's typically better quality than the Columbia Ply that Dixie is married to.

Dave

[Ryan Patterson]

Eric,
I am using whiteside #4100 and #4102. I think my problem was RMP. I managed to get through 40 sheets today with the same bit. Cutting at 6 ips with rpm at 12000. I have tried McEwan a while back. I think I had a tough time cutting their prefin. I got a unit of their prefin birch in today. Will be cutting the birch in the next few days.

Dave I have not looked into Whittelsey most of my suppliers come from Sarasota

[elcruisr]

Ryan,
thats a good tool so you should be able to get good life from it. I think you're on the right track with the rpm. I'd contact whiteside and get a recommended chipload from them and you could really zero it in nicely.

Eric

[bleeth]

Ryan:
Whittelsey Woods
West Coast Warehouse
10060 Amberwood Road
Unit 9 & 10
Airport Wood Commerce Center
Ft Myer, FL 33913
Tel: 239-561-2321
Fax:239-561-2164

Good sheet Veneer supplier too.

Dave

[Ryan Patterson]

Thank you Dave, my eyes did not read the name right the first time. I do know of Whittelsey have not used them will give them a call tomorrow.

Ryan