Can I cut at 600 ipm? Question answered!

[Jim Becker]

David, try a .25" compression cutter, either full depth or two passes...I think you'll be surprised. The first pass must be just a little more than the height of the up-cut section at the tip of the bit. The Whiteside that I use would make that about .20" minimum depth. The advantage of the compression cutter is clean edges on both sides including where the spoilboard underneath might be slightly buggered from previous cutting. The up-cut section also helps at least a little with clearing chips where a full down-cut, well...you know...keeps stuff in the kerf.

[David Falkner]

I just looked at those on Amazon, Jim. I like to use 1/2" shank where possible but only saw 1/4" shank Whiteside. Have you had any issues with 1/4" shank bits deflecting or breaking? I just like the heavier shank to keep flex and chatter down, have always been leery of smaller shanks... but that's probably just me.

David

[Jim Becker]

Think about it...the business end is 1/4" and if it's going to break in a CNC application, it's going to break there, not up on the solid shank. (That's at least held true for me with .125" cutters with .25" shanks. LOL) You're also going to try and only expose what you really need so there will still be a solid grip in the collet. For this particular application, I don't think you're going to have an issue. I don't know if they have the same kind of cutter with a larger shank. I have two of these cutters and have enjoyed the results. One other things...with CNC and the potential for using these cutters for pocketing, a larger shank can get in the way if you need to go a little deeper on the last passes than the cutting depth on the bit. There's no harm in you trying one to see if it works for your application and at the speeds/feeds you probably will stick to, I doubt there will be an issue...but that's not insurance at all.

[David Falkner]

Makes sense, Jim. I'll order one and give it a shot.

Thanks!
David

[Mick Simon]

Jim is correct. I'd be using a 1/4" compression spiral, 1/4" shank, 2 passes. Your tooling will stay sharper longer at higher feedrates than running at lower speeds, lower chiploads.
As a rule, for end mills the shank diameter should match the cutting diameter whenever possible. Bits with a larger shank diameter that have to be machined down to a smaller cutting diameter tend to break at the point where they're machined down.

[Mark Bolton]

We have much better luck with 1/2" shanks as well however when the application doesnt afford it, or the tool isnt available, your left running a small shank. For tools we run regularly and have sharpened I tend to run the largest shank I can buy the tool in and they are most definitely stronger than a smaller shank as well as having more mass in the large shank for heat dissipation. But for less than production work and with conservative feeds and speeds it wouldn't be as much of an issue.

I dont think I have ever seen a 1/2" shank smaller diameter compression but I have never looked. We run a lot of 1/4" 2 flute in MDF and use a 1/2" shank and they last miles longer than a straight 1/4" 2 flute and are far more rigid.

[Mark Bolton]

Bits with a larger shank diameter that have to be machined down to a smaller cutting diameter tend to break at the point where they're machined down.

I only found this to be true on bits that are (to me atleast) poorly designed/machined that have a small relief ground right at the top of the small diameter which seems to create an intentional stress riser there. Maybe thats to increase tool sales lol.

We get far more life out of something like an amana 45408 with regards to a brazed tool. But other than a single size jump (3/8 shank to 1/4" compression) I never see 1/2 to 1/4 in solid carbide/spirals.

[David Falkner]

I've been using the Whiteside RD4700 and RU4700 and they seem very strong. I know for a fact that the RD4700 will cut at 600 ipm without even blinking! LOL!

Davd

[Mick Simon]

I only found this to be true on bits that are (to me atleast) poorly designed/machined that have a small relief ground right at the top of the small diameter which seems to create an intentional stress riser there. Maybe thats to increase tool sales lol.

We get far more life out of something like an amana 45408 with regards to a brazed tool. But other than a single size jump (3/8 shank to 1/4" compression) I never see 1/2 to 1/4 in solid carbide/spirals.

LMT Onsrud hosts seminars on proper tool use for CNC machining at their Libertyville, IL headquarters. I've been fortunate to attend the seminar twice over the years. Two things really stuck in my mind from the course - plunge really fast to avoid heating the tool (they did a demo at 400 ipm plunge speed) and whenever possible, match the diameter of the shank to the cutting diameter. Their tooling is definitely not cheaply made.

[David Falkner]

That's interesting, Mick. I've always heard and read that a straight plunge isn't good for tooling or equipment. But I guess if Onsrud said it's ok then it's probably ok.

David

[Jim Becker]

I learned quickly to plunge a compression cutter in particular quickly and then move on the cut since you typically are taking a deeper or even full thickness pass with these cutters to take advantage of their benefits. There's more tool "rubbing" the material, so you don't want it sitting there for very long at all. Ramping causes a problem with a compression cutter at the edges until you reach that magical depth where the down-cut portion engages the material.

[Mark Bolton]

LMT Onsrud hosts seminars on proper tool use for CNC machining at their Libertyville, IL headquarters. I've been fortunate to attend the seminar twice over the years. Two things really stuck in my mind from the course - plunge really fast to avoid heating the tool (they did a demo at 400 ipm plunge speed) and whenever possible, match the diameter of the shank to the cutting diameter. Their tooling is definitely not cheaply made.

I dont doubt their advice for their tooling. We are running a brass job right now and are using some of their smaller stuff. I would definitely agree that many of the large shank/small cutting diameter tools I see would most definitely be prone to breaking the way they are ground. The only information I have is from our own experience (not very vast). As I mentioned, we run miles of mdf with 1/4" diameter tooling and have run 1/4 shank, 1/4" cut diameter, tooling and 1/2" shank 1/4" diameter tooling from the same manufacturer. The 1/2" shank tooling outlasts the 1/4" by a mile and with the identical toolpaths you can hear the difference. With the 1/2" shank tooling we will run our machine as fast as the 1/4" tool will allow with the 1/2" shank but we back it down with the 1/4" because you can hear there is less rigidity in the cutter.

The price jump hurts with the 1/2" shank but the life and increased speed are clear at least for us.

[Martin Wasner]

LMT Onsrud hosts seminars on proper tool use for CNC machining at their Libertyville, IL headquarters. I've been fortunate to attend the seminar twice over the years. Two things really stuck in my mind from the course - plunge really fast to avoid heating the tool (they did a demo at 400 ipm plunge speed) and whenever possible, match the diameter of the shank to the cutting diameter. Their tooling is definitely not cheaply made.

The Weeke will plunge aggressively when it can't ramp. Pull out, then go back in at a moderate rate to make the cut. It's weird

[David Falkner]

The Weeke will plunge aggressively when it can't ramp. Pull out, then go back in at a moderate rate to make the cut. It's weird

How was the code generated - Vectric, Fusion 360, etc.? Got any video of that?

David

[Martin Wasner]

How was the code generated - Vectric, Fusion 360, etc.? Got any video of that?

David

It has it's own native environment everything posts to. The software blasts out whatever info, Woodwop then does it's thing. Woodwop has cad abilities, which is what I do most non carcass parts in. Woodwop is super powerful, but you can't build assemblies in it.

I don't have any video of it doing it, just noticed it the other day when I was cutting some bowties for a slab with a 1/4" down bit. I didn't draw the bowties, so it might be a parameter I hadn't seen either. There's a bunch of stuff that's just always on in Woodwop.