How to hold multiple rounds in WEDM?

Got a bunch of small (ie 1/2") rounds I need to figure out how to fixture in a non-auto threading machine. Basic process is to start from the edge, then burn a little part out of the center of the round. It would help so much to gang a bunch of them up and let it burn.

Anyone ever done this or am I crazy?

Thanks!

Fixturing rounds

Machinery_E,

It really depends on how much work you want to put into a fixture.

With a little imagination, you can design a fixture that you will first machine in your WEDM and and then load (and most likely clamp) your rounds in.

One way is to cut "almost circles" along the edge of a bar which has been previously drilled and tapped to employ "squeezing" the round to hold it in the bar.

Then your rounds will have their edges exposed sticking out from the side of the bar and will facilitate starting from the edges.

Clear as mud?

Harrytm

PS ........ the reason I said to final machine the fixture in the WEDM machine was for accuracy in positioning location and squareness.If that isn't necesarily an issue you can machine the fixture completely before mounting in WEDM. I often make disposable/reusable fixtures of this type when accuracy is paramount. It becomes inaccurate as soon as it is taken out of the WEDM.

Thanks Harry! That's makes perfect sense, and that trick of cutting partial circles in a bar should work great! Thanks again!

You're welcome MachineryE.

I've also used "V-block shaped" holes in a bar with set screws to push the round into the vee so you can hold different diameters. You could leave the bottom of your vee open so you can run without re-threading.......

Harrytm

Round holding fixture

I'm thinking about making a nice pin holding fixture for WEDM. I would like to make something that could go up to 1" dia, and hold 8-12 pins(rounds). Anyone ever make one of these? If so I would like to see some pics of completed fixtures or just ideas.

Thanks

pin fixture for wire EDM

Hi 440CC:
I built one that does 10 pins at a time up to 3/4" diameter.
It's for cutting ejector pins (I hate the mess the smell and the racket of cutting them off on the surface grinder, especially the big ones).
I made mine with two blocks connected by two round rails so I can slide the front part of the fixture into the worktank to support long pins.
The front part is 10 Vees all in a row, and the back part is just a surface ground stop plate.
I clock the stop plate in on the X axis, slide the front Vees forward until they're a bit shorter than the shortest pin I want to cut, then lock the front Vees in place.

I wrote a program that allows me to set the return pin length as my reference length and input all the EJ pin lengths relative to the return pin dimension.
I also input all the pin diameters so I can rapid between pins.
I wrote it to do either one or two skims on each pin face after the cutoff.

To use it, I load up and cut one return pin about 0.100" too long and measure it, then reset my reference length, load up all my pins and push the green button.
I can walk away and let it burble along by itself.
It cuts the pins as accurately as I can make them on the surface grinder but it is quite a bit slower.
Biggest benefit though is that it's autonomous, and EDM wire is a lot cheaper than my time.

The fixture is very simple, just a couple of hardened Stavax bars and two big ejector pins for rails.
I made a dozen locking screws with knurled heads out of brass and turned a cone point on each so I can grab pins down to about 0.0313" diameter.
I wired the holes for the rails to be a nice sliding fit, and wired the Vees just big enough to accept 3/4" pins.
I made them teardrop shaped with a roof over each Vee so I could tap them for the locking screws.
All together I spent maybe a day making it.
Cheers

Marcus
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