Anyone know wire EDM machines?

[lendaddy]

Just looking to discuss the basic capabilities if anyone here knows them.

[WOODPIE]

lendaddy,

I know very little, really, about EDM machining, other than I've seen a couple of them in operation, and I knew the machinist that wrote the programs, owned and operated them. This fellow built his business in a small out-building next to his house, contracting for tool and die work mostly, using the more conventional machining techniques when he started out. Very smart fellow in a field of smart fellows.

He bought his second, larger, EDM within a year after buying the first one; he was so impressed with the increase in productivity. He added on to his existing space to house the machines and enlarged his measuring room. The parts cut on the EDM required minimal amounts of secondary machining to make them usable in his progressive T&D blocks, or whatever you call them.

I used to have a piece of scrap tool steel he gave me. It measured about 2.5 X2.5 X 3 inches, and it had four identical "U" shaped holes cut straight through the 2.5" thickness. The finish was very smooth and consistent, but wasn't a ground or polished kind of finish.

Reading through this, I'm doubting that I've told you anything you didn't know already if you're in the metal working business, but, hell, nobody else had much to say.

Ed

[Jared at Pelican Parts]

are you looking to buy one for home use? industrial use?

PM me and we can talk

[snowman]

You can remove broken off taps from holes with them. You can machine ANY shape you can draw in ANY material.

[kycarguy 935]

I am currently learning the wire EDM in school and have been using one for about a month now to make a few tools. Its a real unique tool to use.

[IROC]

I've designed alot of things that could only be fabricated by EDM, but that's probably nothing to brag about. :>)

Seriously, EDM is a great tool. One of the major benefits is that you can "set it and forget it". Once it's up and running, it doesn't require much care and feeding. It also works well on materials that are typically difficult to maching (CC455, Inconel 625, etc.) and can easily machine geometries that are difficult using conventional machining.

Mike

[lendaddy]

Thanks guys. I am looking to understand the process a little better. I have an industrial application that I would like to try. It's a two dimensional application so the CNC stuff is not required, think of it as a simple material cut-off process(it's more than that but for discussion purposes that will work). What I'm finding difficult to get info on is real world speeds. Can any of you guys ballpark speeds for me? Most of the work would be on stainless steels. Quality of cut is zero corncern as I know how good they are and we would be more than willing to sacrifice some surface finish for speed. Basically a down and dirty application of wire EDM. Thanks

[81 930]

I took a job as a tool & die maker while in college and have a couple years of experience on Mitsubishi and Sodick wire EDM machines. They are certainly not fast at doing what they do. But, one can produce parts that would be extremely difficult or impossible to make otherwise. I often maintained tolerances of +/-0.00005 on some of the aerospace parts I worked on. Normally, most wire EDM machines are setup for .008 brass wire. Some machines can use up to .012 or .013 wire for heavy cuts. Even then, you will probably only get around .25 inches per minute depending upon the material and it's thickness. Although, there may be larger machines that are capable of larger wire and faster speeds as my experience goes back about 15 years.

That being said, if the quality of the cut is unimportant I would recommend waterjetting instead. It is a much faster and cheaper process and can be found more readily than wire EDM. You can even get a fairly nice finish with a waterjet too.

Best of luck to you, and let us know what you decide upon.

[lendaddy]

Thanks, waterjket is out as the workpiece is not solid. Think of it as a honeycomb, which eliminates laser/plasma, and waterjet.

[lendaddy]

I would also add that the normal tolerance for this are +/- .010" so there is no problem there. Actually the honeycomb analagy is excellent. Think of it as 4' x 4' bars of stainless steel honeycomb (.070" web thickness) and you just want to cut it into 2" sections or "wafers".

[island911]

Originally posted by snowman
You can remove broken off taps from holes with them. You can machine ANY shape you can draw in ANY material.

He's asking about WIRE EDM.

. . .would you use a bandsaw to remove a broken tap in a hole? Wire EDM is obviously a subset of EDM.

Good content here, otherwise.

Len'dy, just check that your material type is reasonably compatible.

[lendaddy]

Thanks Island, the material isn't a problem. 304 S.S. mostly with some 400 series. Anyway, your thinking is correct (replacing a bandsaw) in theory. The lack of burrs, chips, and accuracy are the advantages. Cost, speed and ease of use are the disadvantages. I would just love to see some real world examples IE:

Cutting 20linear inches of 1" thick stainless plate takes 1 hour and $25 worth of wire. Or something like that. Just ballpark stuff assuming best efficiency.

[island911]

If standard cutting tool presures are a bit much, fo r delicate sections, you could (depending on geometry) fill the hollow sections (think wax, frozen water) . . . then go at it with conventional blade.

[David]

We don't use one, but I had a go no-go gage made for a turbine blade root. It was 304SS about 1" thick. The cut was about 6 inches long and it cost me $400. They said it took a few hours to make. Of course it was it extremely precise.

We do use our waterjet alot. Do you have a pic of the piece you're cutting, the waterjet may work and would be much faster.

[lm6y]

Can't help you on the EDM itself, but I polish tools, and dies for a living, and would much rather polish a good wire EDM burn, than the carbon electrode type. If that helps any at all.

On a side note, 90% of the companies we polish for are going to the high spindle speed machines. Maybe the price on wire machines will come down.

[kycarguy 935]

For time comparison I cut some parts to make a parallel clamp. I just now measured the total distance of the cut and was close to 11" and close to an inch thick. Not sure of the exact type of steel but was told it was really good tool steel, the best we had in the shop. Each side took about 4 and a half hours to burn. After I was finished I put it on the surface grinder and gave it a nice sheen. Before I was finished I polished it up with a buffing wheel. It was real easy and didn't take long to polish up the areas just cut.

As far as the wire comes in large spools and its about $100.00 a spool. I think the wire spools are measured by weight. I'm not sure how much it uses but not much. We haven't changed a spool for awhile and when I was done it didn't look like much was gone.

The good thing about this machine is you set it up and go work on another machine. When I was working on this I was also cutting a aluminum block on a Bridgeport CNC and cutting a custom auto body dolly on the engine lathe.

[kycarguy 935]

Here is a link to understanding wire EDM process for those interested:

http://www.manufacturingcenter.com/tooling/archives/1199/1199edm.asp