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Vertical 4th Axis Rotary Tombstone?

dstryr

Diamond
Joined
Jan 22, 2010
Location
Nampa Idaho
I have a part that we are entering production on where I'm looking at building my own tombstone I can attach to the rotary table and get atleast 2 sides filled with parts.I was wondering if anyone could share their design or things to avoid when designing one of these setups. I'm going to have to lift my 4th axis about 5" off the table to get it to all fit (done this before with no issues) and I'll need a tombstone about 18" long x 4 x 4. I'd like to mount it all to a ground plate so that I can pull the whole setup off the machine complete and store and then won't have to bolt everything back together when I want to reuse. Also, I was thinking of making the end support slideable so that I can change pallets easily as well.

Thanks in advance

Dennis
 

jvangelder

Aluminum
Joined
Aug 29, 2010
Location
Southern NH, USA
We do this currently with smaller parts, ie size of a finger.

One thing we did wrong was make the tombstone to large, our small parts stone was 4x4, and with a 1/4x1x1.5 part standing up verticaly, you couldnt get tools to the bottom of the part when rotated 90*, the tombstone was infact to large.

-Jacob
 

dstryr

Diamond
Joined
Jan 22, 2010
Location
Nampa Idaho
Yeah i have encountered that with normal 4th axis operations. Hard to get smaller tools down to do side operations. What about design of the tail end? Anyone have some cad models they would be willing to share? I want to make sure i nail this on the first shot.
 

cybergomer

Aluminum
Joined
Jun 7, 2011
Location
Winnipeg, Manitoba
Here's one of my setups. The tooling block is 4in square 26in long and we've got the Rotary hanging off the end of the table by 6in.

With this setup, we can machine on 7 different sides of the part.


Full Assembly.jpg
 

Radar987

Cast Iron
Joined
Dec 30, 2011
Location
CA
If you have a Haas Factory Outlet nearby, swing by to look at the newest model of the Haas TL-1 lathe. The tailstock runs on the same THK linear guides as the main carriage. Rather than using a clamp, a lever operated pin locks into detents spaced 4" apart along the length of the bed. Such a setup would be nifty on a rotary.
 

John_B

Cast Iron
Joined
Jun 25, 2011
Location
Georgetown, TX

I got one of these from Trunnion Table.com, it's nice but if you decide to get one make very sure it is in fact going to be drilled to match YOUR faceplate! I was told that the one I ordered would be matched to my faceplate, even gave them my brand and model so they could get the specs for the faceplate off of Yuasa's site, yet it came in with the center bolt hole too low to align with the t-nut slot. So now I only get 3 bolts to fasten it down, the 2 holes at 2 and 10 oclock, and the one at 6 oclock. I'm not real please with that for a supposed custom unit!

I would vote to build your own (I know it sounds like that was your original intention). The TrunnionTable brand one I have uses a steel tube for the pin, and a brass sleeve in the A-frame.
 

Pete from TN

Cast Iron
Joined
Apr 27, 2008
Location
Maryville,Tennessee
Here's probably a real stupid question..... I just got my VMC running here and while it is fourth axis prewired and the control can apparently use one I do not have one. Has anyone ever done anything like this with say a MANUAL operated rotary table and just lived with rotating the fixure with a dwell in the program? It would surely be nice to have the automatic rotary but it would only take a couple moments to stop the program and unlock the table lock and rotate it 90 degrees or 180 or whatever you need...?? Having the ability to mount multiple parts onto the tombstone and machine multiple sides could really come in handy and speed things up even if you had to index it manually I would think but having never done it I am not sure. Has anyone here ever tried this? Also why the hell do they call it a tombstone? Kinda grim no? Perhaps a superslab would be a better name or the All purpose magical parts production improvement implement.... an APMPPII for short LOL....peace

Pete
 

cybergomer

Aluminum
Joined
Jun 7, 2011
Location
Winnipeg, Manitoba
Did you just shim to get the end support perfectly aligned ? Also, what do you use in the center? Large dowel pin?

Didn't have to shim to get it straight. The A-frame at the end was an off the shelf piece from Haas. The rotary and the A-frame support are both keyed to keep alignment. Both ends of the tooling block have 2 inch pins pressed into the aluminum block, turned between centers to keep everything running true.

I know Haas used to sell the tooling block with a ball lock system for mounting sub plates, but at the time they didn't make one big enough for what I wanted.
 

escott

Aluminum
Joined
Mar 15, 2011
Location
NH USA
Here's probably a real stupid question..... I just got my VMC running here and while it is fourth axis prewired and the control can apparently use one I do not have one. Has anyone ever done anything like this with say a MANUAL operated rotary table and just lived with rotating the fixure with a dwell in the program? It would surely be nice to have the automatic rotary but it would only take a couple moments to stop the program and unlock the table lock and rotate it 90 degrees or 180 or whatever you need...?? Having the ability to mount multiple parts onto the tombstone and machine multiple sides could really come in handy and speed things up even if you had to index it manually I would think but having never done it I am not sure. Has anyone here ever tried this? Also why the hell do they call it a tombstone? Kinda grim no? Perhaps a superslab would be a better name or the All purpose magical parts production improvement implement.... an APMPPII for short LOL....peace

Pete

You mean putting an option stop with a retract, and indexing the part? Common practice not necessarily with a rotary table, but with other fixtures or index blocks. No reason why it can't be done, but then your part production stops until you can change things.
 

Pete from TN

Cast Iron
Joined
Apr 27, 2008
Location
Maryville,Tennessee
Interesting.... Am I understanding that thing correctly, when you push down on that plunger it kinda auto indexes to a set degree? That is pretty cool if it is, I was just thinking a manual simple rotary table setup with a tombstone and tailstock like the auto boys are using to allow the similar setups. If that is indeed a plunder that needs to be pushed down to index I would imagine you could possibly use at blank or solid toolholder to push it down so it was kinda automated.....Or am I completely off here and that is not at all how it works.... Interesting tho and the Yuasa super accra dex I used to have was a very nice piece. Wish I had not sold it. If I can ever get this new VMC to be reliable and start making some money with it that is a possibility for small parts for sure. Even if I had to index it manually it would still be worth while to allow you to move quickly between setups without having to take anything down or needing multiple vise setups. Peace

Pete
 

Pete from TN

Cast Iron
Joined
Apr 27, 2008
Location
Maryville,Tennessee
LOL nevermind....

Just saw that there are some videos there. Pretty damn cool. Another stupid question. does the distance it is plunged determine the angle it turns or is that something you preset? How much does one of those monsters cost anywyas, probably almost as much as a real cnc indexer....peace

Pete
 

dstryr

Diamond
Joined
Jan 22, 2010
Location
Nampa Idaho
Have you noticed any difference vs using a center in the end and just an end support? I was told that using a center in the end is bad....
 

dstryr

Diamond
Joined
Jan 22, 2010
Location
Nampa Idaho
Y as in why is that bad?
Never noticed a problem and we hit things pretty hard.

Rotary fixtures for 4 and 5 axis rotary tables

However, providing such support is not as simple a procedure as it may appear. If pressure is applied, say by a standard live center, to the fixture, any sloppiness in the rotary table construction will result in the fixture loosing its’ free-standing parallelism. On the machine that makes these fixtures, minimal contact pressure results in a taper of .001 per three inches of x-axis travel. A robust contact pressure causes a taper of .004 per three inches of x-axis travel.

The ideal method of support incorporates a bushing pressed into the fixture and a support pin that is firmly secured to a tailstock, but does not exert any pressure along the long axis of the fixture. The specific purpose of this tailstock arrangement is to resist forces in the z and y-axis.

This guy knows his shit and this is his recommendation. Have you noticed any of this?
 

SteveinAZ

Stainless
Joined
Aug 20, 2007
Location
Snowy Arizona
Dennis, I meant to post this up a while back but ran into some technical difficulties with using Photobucket and forgot to come back to it. I could not post the entire tombstone as it was loaded with customer parts, but will give you pics of the business ends...what's in the middle doesn't really matter here anyway.



Here is the Tsudakoma Rotary with the 5" square tombstone and 12" diameter faceplate/tombstone base - we use two Jergens ball Locks to hold them together. The faceplate has two 3/4" dowell pins and the baseplate is notched to match - this is for easy loading of the tombstone with the crane, and the ball locks will slip right in when it's resting on the dowels. Of course this is rotated 45 degrees so you can see the goodies, but we load at "A" zero. You can see the baseplate and the tombstone column are welded together; they were doweled and four 3/8" SHCS were holding them together, but we started getting repeatability issues and found they were slipping slightly under load, so we indicated the two tomstones to the same rotational locations, tack welded them, threw them back in to make sure they had not moved, and then put a bit more weld on them to seal the deal. They don't move anymore.

IMG_1012.jpg



Here is the tailstock end with a sliding pin to engage a sealed bearing pressed into the end of the tombstone which is turned to a 4.500" OD. The sliding pin rides in a brass bushing and has a detent and spring loaded ball set screw on the top to keep it in place when it's running. The tailstock and Koma rotary are mounted on a 1.50" thick subplate (plus their own base plates were cut so the centerlines match), and they overhang the machine table a little so we still get most of the machine travel. The Koma table and tailstock are doweled into the subplate and the subplate is doweled to the machine table for easy realignment when we need to pull any of it.

IMG_1013.jpg



This is another view of the tailstock; there is a height adjustable Vee block that supports the 4.5" round section of the tailstock when loading. We bring the tombtone over the vee block and dowel pins, slowly (can that actually be done with a full load of parts???) lower the tombstone onto the 3/4" dowel pins and vee block, slip in the slider pin and the two Jergens pins, snug up the ball lock set screws and push the green button. We can swap the two tombstones in about 3 minutes after some operator practice. This load of parts runs about a 2 hour cycle, so we can usually get four loads attended and one load unattended per day pretty easily. This is WAY better than moving these parts through four double station Kurts!

IMG_1016.jpg


Hope this spurs some ideas for improvements over this set up, but of course you have to post pics!

Steve
 








 
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