Ganging up plunge work...

I recently loaded up a fixture that holds ten electrodes and ten parts and burns them all simultaneously.
I'm not seeing any benefit to this ganged up fixture what-so-ever.
My burn time saves nothing over burning pieces one at a time, the fixture set-up is a major PITA. Even my electrode wear seems to be greater than burning one at a time...
Sure I'm saving tank drain time and the time it takes to position to each individual part but in my opinion, it's not worth it.
Anyone else come to similar or contradictory conclusions on ganging up ram work????

I learned that EDM cuts one spark at a time, regardless of how many tools you have on the ram.

Tim

Been there done that. Some jobs are just to much fussing around to gang up, and are easyer and as quick one at a time. We do have several jobs where ganging up is easy and the way to go, like cavity bar inserts with multiple cavitys, put two to four bars on, and run electrodes with three or four cavitys each.

Bill

My experience has been the same: rarely does it pay to build a fixture to hold multiple parts unless you want overnight or unattended run time.

TMD

Ganging up makes sense if you have no CNC and no ATC and want longer untended operation.

But with ATC, todays controls and positioning accuracy, you are rarely going to see any advantage to running a ganged electrode. Ganged workpieces yes, but electrode no.

With very small electrodes on an older control you might see some advantage just because of the increase in surface area.

Tim in D is correct. Standard machines provide only "single-lead" machining, which means that no matter how many electrodes you have, there is only one spark occurring at a time. Additionally, if there is a problem with a single electrode/cavity, all others will suffer. Remember the five and six-wire EDM's designed for production? They are extinct because they were single-lead and no matter how many wires you had engaged, you were only as fast as the slowest one.

In this particular application, perhaps the parts can be executed one-at-a-time during the attended day-shift for efficiency's-sake, but run in multiples overnight. However slow the overnight operations are, this can increase productivity in machines without an ATC.

To realize the full advantage of multi-part machining, individual leads from the generator to each electrode must be made and this is called "multi-lead" machining. This configuration will produce the cutting speeds you are seeking.

[ 05-03-2007, 04:26 AM: Message edited by: Bud Guitrau ]

I never had much luck ganging up electrodes, about all I ever got was DC arcs.. Years ago, I knew a guy that did a repetitive job that did use ganged electrodes. It was some type of mold insert for a car battery maker, he ran it in an Eltee, and I do remember he had a seperate lead to each electrode...