Is there a word for moving a part when there isn't enough X and Y axis?

[slashmaster]

I know that if your machine doesn't have enough X or Y axis to build what you want that you can sometimes turn the part or slide it over to do the part in more than one section. My question is what do you call it when someone does this? Is it difficult to get the area's to line up when you do this? I just want to know how much trouble it is before I buy my mill.

[flick]

I'm not aware of a particular term for the technique. What requires a single setup on one machine can require many setups on another machine, for many reasons other than the size of your work envelope. So it's really just "using multiple setups", regardless the reason.

It can be as hard or as easy as you make it. With good fixturing it is a reasonable technique for mass production, with poor foresight you could really waste a lot of time on even a single part. The key is to always bear in mind that you need a good reference point/edge/plane that can be positively located during both setups, so you can use it to fix all 3 axes before and after the move. Finding the reference can be done with fixturing, a dial, an edge finder... the list goes on. Sometimes it may be worthwhile to create a temporary reference during one setup that can be used as a reference to locate, but is then milled away during, the second setup.

Anything that can be said generally about machining a part in multiple setups applies to the case of a part that doesn't fit in your work envelope. I'd say it's the single most important, interesting, and challenging part of machining, period.

[Med-Pac]

I think the termanology your lookin for is indexing. We've done that with our plasma and router before, don't see why you couldn't do it with a mill.

hope this helps ya
Mike

[ctate2000]

Damn is the word I used to descibe the situation.

[TOTALLYRC]

The G-code for damn hasn't been written yet, but I hear they are working on it.

I used to do this way back when I was a button pusher in a cnc shop.
The first part of the code would be run, including a feature to be picked up when the part was repositoned on the table. We would then relocate the part using the hole from the first operation, set this as part 0,0 and then run the second operation. this part was in 2 vises and would just be slid from right to left so all you had to do was find the center of the hole and you were good to go. It was a little bit of a pain to do, but when machining the ends of a 6ft part on a 3ft travel machine, you didn't have to flip the part and we were accurate to within a few thou over 4 ft IIRC.

I forgot to mention that we used a boring bar to finish the relocation hole to be as accurate as possible. If the hole is out of round or has a lousy finish, it will effect the final length of the part.

Mike

[DerbyCountyFan]

I am having the same problem with a 97" part and 84" travel....

My mill has inputs on the back for hooking up hydraulics, pnuematics, servos, etc. You can use m-code relays to control these.

I have never done this, but I am about to try. I do not want to have multiple clampings.

[ctate2000]

I hsve lots of words for this problem. I can not use any of them here.

[wwendorf]

I had a part that I was doing recently that I had to do this on.

I had to machine a 15" part, but my Syil SX3's envelope is about 14.5"... Grrr... So, I just did 1/2 of it... then bumped it over about 4" and finished the other side of the part. Once I was able to visualize it in my head, it wasn't too hard to do.

Wade

[ImanCarrot]

"Sub Contract It" or "No Bid" is the phrase I use

[BobWarfield]

Originally Posted by TOTALLYRC The G-code for damn hasn't been written yet, but I hear they are working on it.

I dunno, "g0 z-1000" will usually get at least a "damn" out of me!

Cheers,

BW

[TOTALLYRC]

Originally Posted by BobWarfield I dunno, "g0 z-1000" will usually get at least a "damn" out of me! Cheers, BW

Touche'

Mike

[metalworkz]

Hello,
I work with a CNC turret punch and we call this 'repositioning'. The older turrets commonly have 72" X travel and 48" to 50" Y travel, but the machine has the capability to automatically reposition a sheet(the machine moves the sheet under the turret and there are 2 hydraulic hold downs that grab the sheet and hold it while the pneumatic clamps unclamp and move to the repositioned clamp zone and reclamp the sheet, and the punching program will resume from there. At the end of the program the sheet is usually repositioned to the beginning position so it will return to the home position without overhanging the machine.
Yes, on a machine not equipped with an auto-repositioning feature it can be a pain but is one way to accomplish the task with the smaller axis travels. I have done some 3D machining on my small SX3 CNC mill that needed several repositions in the X and Y axis and was quite a task but very rewarding to have accomplished it.

Regards,