Long toolholders for 5 axis work

Hello all,
Recently purchased a Mazak VC-500 5 axis to replace a smaller 5 axis machine. issue I am having is reaching the part with the table rotated 90 degrees. I have had to switch to some 6'' gage length Schunk Tendo holders to reach the part and we are getting some vibration & chatter. Has anyone epxperienced this issue and possibly tried different toolholders? Roughihing & finishing with a .500 endmill cutting 13-8 H950. Looking into some Rego-Fix Powrgrip or maybe shrink-fit.. both are a bit of an investment as with either system we need to buy an accessory unit to assemble the tools.
Any suggestions?
Much appreciated.

Have you looked at increasing the fixture standoff from the table so you can (hopefully) gain clearance to allow shorter toolholder use?

If not, playing around further with endmill choice, speed and depth of each cut should allow finding stable cutting parameters. Heck, even getting longer holders than you have now may improve things. Machine resonances are funny things...

I'm doing a 'Deep dive" on Rego-fix myself (that's a project), so would be interested in any comments from the wisdom of the forum on this also.

@dcrace I hear the accessibility to parts on the VC-500 5 ax is not that great / limited X travel. I see that MAZAK demos for non impeller parts use a 60 degree (ish- I'm guessing) slanted fixture for parts so that shorter tool lengths can be used + better accessibility to the part (with the trunnion tilter over). Seen that on a number of demos for different machines from MAZAK.

* Just saw milland's post.

cameraman said:

* Just saw milland's post.

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Hah - beat you...

On the Rego-Fix - I used the holders and automatic setting machine for a while, and I certainly liked them, but they had drawbacks. Biggest one is they really have to be scrupulously clean, any particles in the taper fit will damage the holders and concentricity. Tool stickout must be controlled, or more accurately, you must have a minimum shank engagement.

And then there's system cost. Frankly, if it was my money, I'd be more likely to pursue shrink fit if I had to go with one or the other.

Our main issue is the gage length distance from the center of the table to the spindle nose with the table at 90 deg. which is 160mm (6.299) This particular part is fairly small and we need the extended reach to get a few of the tools to the center-line of the part hence the need for the 6'' length holder.. been testing some toolpath parameters, but even getting some small chatter/vibration on the finish cuts with as small as a .005 stepover. Bit of an oversight not knowing the Z axis travel limits, but hopefully we can get this sorted out. I see Haimer Makes a Power-shrink heavy duty shrink-fit holder with a 5.12 gage length. Luckily we are close to the Mazak tech center so I can try to get a toolholder on trial and use their machine to load up some tools to test. Never used any shrink fit so not sure of rigidity benefits over the Schunk hydro if any..

All of my extended reach shrink fit holder is Haimer powershrink. Don't waste your money on other MFG extended noodle holders

Can you share what you are trying to do?
I bet an easier way is to put the part on an angle and push it off center if you only need to reach certain sides

Another thing you may want to try is getting the spindle checked out for improper bearing preload. If for whatever reason the bearing are too lightly loaded, or suffered damage due to crash, etc., then the spindle might cut fine in less loaded conditions (shorter holders), but allow chatter with longer leverage.

Let us know what finally resolves the problem.

dstryr said:

All of my extended reach shrink fit holder is Haimer powershrink. Don't waste your money on other MFG extended noodle holders

Can you share what you are trying to do?
I bet an easier way is to put the part on an angle and push it off center if you only need to reach certain sides

Click to expand...

^^^
Apologies for gratuitously commercial video but shows a 60 degree fixture on the UD-400 5ax. (not 100% sure why they had to do that in that particular instance but maybe the apparent lack of Z travel (again) … but lack of Z should = better rigidity ??? + shorter tool length. ~ That is supposed to be one of the major promises of 5 axis "Shorter tool lengths" (outside of big spindle head, and big tabled universal "Type".). Having dynamic work offsets and full transformation capabilities (rotations and translations/ offsets + "Other" (scaling and shear) + ability to probe. Things don't have to be set on orthogonal axes and at the center of rotation, especially if your part is not an impeller.).


^^^^ (apologies again for "sales video" BUT good for Same principal again but showing dstryr's off center idea + what looks like a 45 degree tilted fixtures (twin). There the tools also appear much shorter than a part fixtured at center of the table.

The MAZAK west coast "Peeps" seem friendly and willing and able.

You can scroll through to the relevant parts of the video.

The impellers I saw being done on the VC 500 5ax were quite large , like 11" in diameter if I remember rightly (looked pretty nice a whole heap of them lol).

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@dcrace which spindle option did you get on the VC-500 5ax (if you don't mind me asking ?)

Ta.

There is one good reason to avoid (if you can) going off center on the table, and that's due to the increase in geometric error as you go further from the center of rotation. But if it's a good machine, it should maintain adequate control of the geometry out to the furthest extents.

Milland said:

There is one good reason to avoid (if you can) going off center on the table, and that's due to the increase in geometric error as you go further from the center of rotation. But if it's a good machine, it should maintain adequate control of the geometry out to the furthest extents.

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Aye , indeed,

I think in the case of the UD-400 video , looking at it now they used that 60 degree fixture to in essence slant the table away from a "Big head" / spindle head... or give extra clearance to sneak in a big head ~ but also seems to work better for that type of part, helps reduce large rotational arcs (in cut) where the XYZ orthogonal axes would have to move larger distances for sim-5 axis contouring.

Some large tabled machines I had to map out to get to a smaller part at the center especially with an older style large boxy spindle head can become a bit of nightmare as the part (like a small radially symmetric prismatic part - almost a 4th axis part) has to be fixtured 8" + off the table, so you still can get that radial vector or tilt error, although some 5 axis machines have the table drop lower in relation to it's trunnion axis / nodal point which means when parts are fixtured 8" off the table it is still closer to the centers of rotation all be it less rigidly.

I think there's a lot to be said for trying to find a table / 5 axis machine geometry that most closely fits your part's envelope. But on the other hand these Universals are intended / always have been designed with the idea of a 3 axis machine with additional capabilities … Like some of the old school German universals that were hybrid manual and 3 axis cnc. Seems the functionality and intended use of these "Universals" have been greatly expanded (in more recent times).

Seems a number of folks seem dissatisfied with the VC-500 5ax* for similar reasons that OP / dcrace cites .

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* CV5 500 5ax is newer UK designed and built machine, and VC-500 5ax from the VCU 500 5ax (older machine designed and built in Kentucky.). UD machine is designed and built in Japan.

cameraman said:

Seems a number of folks seem dissatisfied with the VC-500 5ax* for similar reasons that OP / dcrace cites .

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Not to poop on the OP's new machine, but when I watched this video of it I wasn't overwhelmed by the surface finish and "sound" of the spindle cutting. And considering it's a puff-piece for Mastercam, you'd think they'd program to impress.

YouTube

[I am known to be a fussy bastard, though]

I unfortunately can't post a picture of the part we are making but it has to be at the center of the table as we are machining 5 sides of the part (1.0 wide x 3.15 long). The machine is brand new so hopefully the spindle isn't an issue. I will be reaching out to Haimer so I can get a couple of holders in here. The power shrink has a 5.13 gage length... even though its only an inch shorter than the 6'' holders we have now, I am hoping that makes the difference.
Again, an oversight on the travel limits of the machine, especially upgrading from a smaller 200mm machine..
Thanks to everyone for their input.

Milland said:

Not to poop on the OP's new machine, but when I watched this video of it I wasn't overwhelmed by the surface finish and "sound" of the spindle cutting. And considering it's a puff-piece for Mastercam, you'd think they'd program to impress.

YouTube

[I am known to be a fussy bastard, though]

Click to expand...

^^^ Lol. Me too right … I think it's the "Avoid disappointment" for shelling out a ton of $ and have lack luster results/ sucky / sucktastic surface finishes. Your part might meet nominal tolerances, technically be fine on a CMM and yet still look like sh*t lol.

My local MAZAK sales "Peeps" older and newer had always pointed me away from the VCU's towards Variaxis machines.

I have seen that video before and remember thinking that's a pretty sucky test part. But kinda funny/ very relevant to OP the three or four stickers stuck to the table for MASTERCAM, PREGO-FIX, KENNAMETAL … (+ HSK tool holder) Table tilted at about 30 to 45 degrees and long/high fixture and long long tools at the end. If the spindle has 3 micron runout + runout of tool holder + tool at considerable length at lower RPM (lower than what you'd ideally want for surfacing), you'd be edging towards 10 micron runout at least for that longest tool*. Even on a Makino you'd need the super duper real time surfacing / surface / geometry processing algorithms (SGI super geometric intelligence ) as even there, fine surface features for mold work would get a bit knarly / smooooshed up.


Although hard to know unless you have the test part in hand.

Also there's still in some cases [sim 5axis] contouring versus [3 axis contouring + 5 axis positional moves ] : Which one is better and faster ?


For prismatic / positional parts the VC -500 5ax should be OK … I mean folks have had other problems.

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* Odd that the HAAS UMC NEW 750 reboot had fleeting moments in their demo videos of using super long long tools and surfacing that you never in a million expect a HAAS 5 axis machine be capable of + limited block look ahead ?



^^^ But big faceted "space part" with long tools through the part using HSK interface + (shrink fit … I think ?), that's at 2 minutes 30 seconds in. Part looks pretty damn good but again have to have it in hand.


Annnnnd just for completeness 'cuz dstryr might be hanging out, ^^^ super long skinny tools going through the part for contouring. It's Grob thing, and maybe a Hypermill "Thing".

Milland said:

Not to poop on the OP's new machine, but when I watched this video of it I wasn't overwhelmed by the surface finish and "sound" of the spindle cutting. And considering it's a puff-piece for Mastercam, you'd think they'd program to impress.

YouTube

[I am known to be a fussy bastard, though]

Click to expand...

I've got to agree with you on the finish. I think the spindle noise was just bad microphone placement, at least I hope it was. After watching that, I wouldn't have wanted my name all over it.

A number of the tools in that Grob video look like shrink-fit to me. Some of them fairly large (1/2"?)

I had good luck with the low profile hydraulics form Kennametal but they were pricey. We didn't use any shrink fit in the shop, though.

I use shrink to reach the center of my trunnion (4" holders, smaller trunnion than you.) You can get started with just a MAPP gas torch to test it out. After doing that for a couple months I bought the cheap induction machine from Maritool.

First I will state the obvious, use variable flute, helix cutting tool. Next stay away from shrink on the long holders, they are notorious for chatter. You will have your best luck with hydraulics for the vibration damping abilities, but you have to watch the clamping power, I have had them pull with an enthusiastic cut.

Milland said:

Not to poop on the OP's new machine, but when I watched this video of it I wasn't overwhelmed by the surface finish and "sound" of the spindle cutting. And considering it's a puff-piece for Mastercam, you'd think they'd program to impress.

YouTube

[I am known to be a fussy bastard, though]

Click to expand...

In some defense of that video (since I was there - Mazak AE), it was a last minute demo Mastercam added to that machine for an open house at Mazak Northeast years ago. They had a couple post issues that slowed things down, so we weren't able to do as much cutting development before the show. Certainly could have been a lot more polished, but it worked for it's intended purpose. The sound is purely from the GoPro, it sounded just fine in person.

As for the OP's problem, the table on a VC500 is 500mm diameter, so ~19.69". He's doing a part that is 1" x 3". There's no way around it, you're either gonna need long tools or tall workholding to do the part effectively when working at 90 degrees on this size machine. I'm firmly in the raise the part off the table camp myself.

CNC Hacker said:

As for the OP's problem, the table on a VC500 is 500mm diameter, so ~19.69". He's doing a part that is 1" x 3". There's no way around it, you're either gonna need long tools or tall workholding to do the part effectively when working at 90 degrees on this size machine. I'm firmly in the raise the part off the table camp myself.

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Cool, thanks for this "on site" report. And yes, if the loss of precision from being further from the center of rotation is acceptable, I agree - stiff tall workholding is better than longer toolholders.