Mill "C" Axis?

Bin gunna ask this and keep forgettin aboot it...

I think it was 4 yrs ago at the toy show they had a (import I think) big HMC that was boring out something along the lines of a 3'D bore with a rigid boring bar and the X and Y were moving in unison with the revolution of the spindle (C) to make whatever bore a feller could ever want.

I have never heard of this before or since. Maybe this is commonplace on all newer MC's these days?

I don't remember if this was a Fanuc or what? (As it is MUCH more a control feature and NOT a MTB issue eh?)

I could see this being usable on VMC's just as well as the HMC that it was demo-ed on - other than the fact that the RPM would likely hafta be slower on the smaller holes...

???

On edit - this feature would negate the need for the "U" axis eh?


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The machine was like - swayin' back and forth eh?
Ox

I'm pretty sure that was an Okuma. If you browse their website for videos, I think you'll find a MA630 doing exactly what you're describing.

I koodn't git any of the videos to werk.

????



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I GOTTA git OUTTA here!
Ox

Does not look any different than interpolating a bore with an end mill? Did I miss something?

Dave

Ox,

You're looking for a "U" axis. Here's a video - http://tinyurl.com/Tsugami-U-axis-Video

This vid shows a VMC doing outside turning (because you can see it) but obviously you can turn it around and bore a contour. I think I have some better videos of the machine. If I find them I'll post them.

Not sure who's machine you saw. I'm pretty sure Niigata makes a big HMC or HBM with U-axis though.

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Video Killed the Radio Star

When there's Z/X/C simultaneous interpolation on a lathe, that's called asymmetric turning. Used for lenses and stuff. It got ported over to mills, I think they call it elliptic boring in the HMC/VMC world. The system that enables it is usually called STS or SSS (slow tool servo/slow slide servo).

The ultimate are diamond turning "freeform" machining centers that will single point mold cavities - these are machines with 8+ axes to manipulate a single point tool (no live tools, no toolchanger). Nigh impossible to beat the surface finish without IBM or hand polishing (sorry, you EDM guys).

This stuff isn't really new, but it's just never found wide application because not many people really need that kind of part made.

toastydeath said:

When there's Z/X/C simultaneous interpolation on a lathe, that's called asymmetric turning. Used for lenses and stuff.
This stuff isn't really new, but it's just never found wide application because not many people really need that kind of part made.

Click to expand...

Yea, we have special-purpose, in-house designed lathes that do this. I can basically program a radial dimension for every degree of rotation, for every rotation along the part length, and it can do it at several thousand RPM, and hold +/- 4 microns for the entire shape, except where material conditions exist that require a larger tolerance. (The error isn't in the machine, the error is due to during/post-machining stress relief in the material being cut.)

We also do U axis like interpolated boring and oval boring.

But, these are specialized parts and outside of this and a few other specialized applications, there would be no need for any of the 3 operations.

SwissPro said:

Ox,

You're looking for a "U" axis. Here's a video - http://tinyurl.com/Tsugami-U-axis-Video

This vid shows a VMC doing outside turning (because you can see it) but obviously you can turn it around and bore a contour. I think I have some better videos of the machine. If I find them I'll post them.

Not sure who's machine you saw. I'm pretty sure Niigata makes a big HMC or HBM with U-axis though.

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Video Killed the Radio Star

Click to expand...

Dan, you should check out the videos. It's pretty wacky. They are essentially using the XY axis as the U axis. The machine is interpolating at a very high feedrate in sync with the rotation of the tool, which is a very large, single point boring head. I think I'd much prefer a regular U axis like Niigata or others offer. It would be interesting to see the finish and accuracy of this process.

http://www.okuma.com/products/machines/hmc/ma_series/ma600h/

The videos are at the bottom right.

Joe,

That is pretty cool. I hadn't seen that before. I probably should have known that the Okuma could do that given the amount of time I spend near them.

Okuma has some other off the wall capabilities that are pretty handy. One that I like is a feature on their lathes that will vary the spindle rpm while cutting. This way if you have a deep bore or a long thin part that is chattering, you can break the harmonic.

The Tsugami video shows a boring head that's controlled through the spindle. The axis motors aren't doing anything. The boring head changes OD as the spindle turns. You can see them cycle the boring head at the break between cuts.

There yuh go. I couldn't git the videos to open last night - but I was on the wifeys 'putor. It opens on this one fine, but no sound on this one. Was the audio good? LOL!

No - I aint lookin fer a U axis machine - was just thinking that while this feature would negate the need for a 36" boring head, it would also (I assume) be able to doo U axis werk as well. And I think it did in the one vid - I think it cut a chmfr on the leading edge?

I see no reason that this feature couldn't be expanded into making out of rounds as well with a little more code werk? (as per Tony)


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Kicks are just so hard to find
Ox

Turning Cut

Ox.....

We are having a machined commisioned this week with that very feature. It's an Okuma MA600HB. Okuma call it Turning Cut. We have been "lent" a similar machine, without the option, for the last 6 months while our machine was being built. I posted on another forum asking if anyone had used this feature and got no replies. Gulp! Am I the only one gonna be using it.
The cycle is called with a G code (G183?) and then programmed similar to turning with X and Z. The machine incorporates glass scales and cooled ballscrews.
The option was quite expensive but think of all those boring tools set to cut one diameter. Becomes costly when you do several jobs with various bores. With Turning Cut you'll need just one boring bar for all bores and it'll do bores, tapers, rads, chamfers..... the lot. Won't be as quick as turning on a turning centre but will save a set up and another jig. We do plenty of casting work so work-holding can get awkward. Alot of jobs should be completed in one op....hopefully.

D. Rey......
It's not at all like interpolating with an endmill. Grind three edges off your 4 flute endmill and that one edge has to stay in contact with the material!! Think of a horizontal borer and how that machines a bore. For a bigger bore size, stop the spindle and adjust the tool. Well on the Okuma the X,Y motion is similar the the spindle rotation, and the tip follows to keep it on the cutting diameter. Want to alter the bore size then the X,Y motion is altered accordingly while still feeding in Z.

This is our first Okuma so I was given a weeks training, 6 months ago on our "borrowed" machine, to learn the control. The guy training me said he'd never used Turning Cut, so it looks like we'll be scratching our heads, together, next week.

Looks like fun.

Ah, looked at it again I see what you mean.

Dave

Thing is, you should be able to do this on any mill that has rigid tap, but you won't have a convenient G code cycle you can call, you'd have to program it, similar to a thread mill.

Can't the same be done with polygonal turning and creative programming? Kinda similar to the limited (imo) c-axis from the Okuma's that they call cam-turning and creative programming? I guess the thing is that to creatively program and proof, it takes much more time than a canned dealy for this abnomoly? Just asking.

Polygoning?

As in puting a hex on a round bar?

Those are two/three insert cutters set in time to the main spindle. Nowhere's near the same.

You must be talking something dif. ???


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Think Snow Eh!
Ox

Ox said:

Polygoning?

As in puting a hex on a round bar?

Those are two/three insert cutters set in time to the main spindle. Nowhere's near the same.

You must be talking something dif. ???


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Think Snow Eh!
Ox

Click to expand...

Hex on a round bar is done by polar coordinate. Polygonal turning is say doing a 3 sided radiused part, like needed on a rotor for a vane pump. Synching the spindle, cutter and cutting to produce a multi-sided part without straight cuts or sides. Not sure if that explaines it. You know I have some out of touch thoughts that can be described as somewhat retarded, at times. If I can locate the codes for the 21i-T for the same, I will post them. If not, then forget I even said anything....


But, yes, Ox I am talking different than using a fluted e-mill to mill flats. Offset inserted cutters doing something different like 'curves'.

Hex on a round bar is done by polar coordinate.

Click to expand...

I’m not so sure about that. All the exhibitions I go to, companies like Miyano & Tsugami are putting Hex’s on round stock, and they call it polygon turning.

Swisspro, dumped some good video links to it in this thread.
http://www.practicalmachinist.com/vb/showthread.php?t=118686

Squares and Hex’s on round stock. But you might have a point some where. I’m lead to believe that the flats produced by polygon tuning are not truly flat. But good enough for a spanner.

Regards Phil

I guess that 'polygonal' does mean multi-sided, but not like the polygonal turning I'm talkin'. Hex is done by actual polar coordinate interprolation milling. I've done it, many have. Ever milled a square on an oiler shaft on a c-axis lathe? Yes. Ever made 'drops' on a rotor head for a 3 sided vane pump where the 'sides' are actually radii? Me either. It is a function on a 21i-T on an EmcoMaier machine I know. Maybe something in the area of G21.1....I dunno. Polar on the same control is G12.1. Done with an axial live tool as is the polar.

Somebody needs to scrounge up a video of the operation - including the attachment for you.

Yes - I have of course MILLED many a hex in C mode. This is not considered "polygoning".

Not saying that what'cher talkin aboot aint too...

Don't shoot me - I'm just the messenger. I didn't name the operation. LOL!

I have a "polygon" attachment for my Tornos that uses either 2 or three evenly spaced (120* or 180*) inserts and spins at a ratio to the bar spped to acheive a hex, dbl D, or whatever it is that you are after I spose. ???

They doo make "polygon" attachments for the multispindles that are driven directly off the pickoff gear (1 to 1 ratio) and uses only one cutter - which is essentially just a brazed tool bit like you would use for your lathe 50 yrs ago. (Actually - I guess HS would be more suited for the screw stock eh?) This style uses a custom made cam for just the size and shape your hoping to make and makes the bit recip. (Google Slater tool - I need to be heading in here shortly) I could very easily see this style used to make odd contours.

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Think Snow Eh!
Ox