What kind of EDM should I use?
What kind of EDM should I use?
(OP)
I need some help with this one.I don't know much about EDM's. I build small high speed stamping dies. I want to EDM hardened punch blanks of CPMM4 material. The punches are max. size of 1.5" wide x .75" thick x 3.0" long. They need a profile cut across the 1.5" at one end only thru the .75" thickness. I want cut a piece of the coil I will run and scan
the profile into the program, I may need to make some small adjustments to it( opening up vertical walls a few thou.)Then cut my punch shape out of the blanks so I have an exact fit with my punch to strip. What kind or type of machine will I need? Model #'s would be great! I will need to stay under $50,000, used is okay too.
Thanks in advance for any help if I am unable to answer.
the profile into the program, I may need to make some small adjustments to it( opening up vertical walls a few thou.)Then cut my punch shape out of the blanks so I have an exact fit with my punch to strip. What kind or type of machine will I need? Model #'s would be great! I will need to stay under $50,000, used is okay too.
Thanks in advance for any help if I am unable to answer.





RE: What kind of EDM should I use?
RE: What kind of EDM should I use?
RE: What kind of EDM should I use?
Joe
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RE: What kind of EDM should I use?
RE: What kind of EDM should I use?
One of my employers had a plunge machine. Making a cut required first producing a copper or graphite electrode in a milling machine. The electrodes were slowly consumed as workpieces were cut, so deep holes or repetitive work might require producing many electrodes. Ours had a borderline magical and hideously expensive set of tooling called 'System 3R', which allowed you to remove electrodes for modification and reinstall them to the exact same position, within fractions of a tenth. It was ideally suited for making a cavity in one face of a part, less so for making a profiled edge as I think you want. Note also that you need a fully tooled milling machine nearby, and most of them don't much care for machining graphite.
A wire EDM machine does not require a milling machine to make electrodes, because the electrodes come on a spool. It's not good at all at making blind cavities, but excels at profiles. I think it's commmon now for such machines to be able to produce a punch, a stripper, and a die with back taper/clearance, all from the same shape description, with adjustable clearances and drafts, and to do unattended piercing of a blank for cutting holes.
EDM is inherently a slow process, so unattended operation is a critical basic requirement; set it up, go home, and retrieve your finished part in the morning. It gets much slower than the usual claimed speeds when you need a good finish or tight tolerances.
Mike Halloran
Pembroke Pines, FL, USA
RE: What kind of EDM should I use?
As for surface quality, we cut our punches on a linear surface grinder. So what type of finish would that be and how many passes of EDM would it take to achieve that? Also, could I have a warping issue cutting CPMM4.
One source I found said to use cryogenics to control it. (sounds a little far out to me).
How long does it take to make one cut across a 1.5w x .75 thick stock?
RE: What kind of EDM should I use?
As you try to push the speed, the finish gets rougher and rougher. At the lowest speed you can stand, you get a satin finish.
Talk to your dealer about the metal removal rate you can expect, and ask for some sample pieces to show the finish.
One important way in which EDM differs from grinding is that it doesn't leave behind any locked-in stresses. ... which is actually not good for fatigue life of cut parts.
Mike Halloran
Pembroke Pines, FL, USA
RE: What kind of EDM should I use?
Regarding cryogenics...When heat treating metals, quenching gives a desired structure change to the metal. Often quenching to room temperature accomplishes this. Some tool steels, however, do not have 100% structure change at room temaperature. Cooling these metals further (say ~-100°F), completes the 100% transformation. If you don't do this there is some residual stress left in the material. Your application will dictate if this residual stress is a problem. If you wire edm a very thin section out of a larger block, the work piece may move due to the residual stress. It is very application specific, so I suggest you try it without the cryogenics until you see a problem.
RE: What kind of EDM should I use?
I think you are really minimizing the cost of 3R tooling. Hideously expensive is the understatement of the week!!
But it's darn repeatable and fun to work with if you can swallow the price.
But back to the question at hand. This could be completed with either sinker or wire EDM. You would just need the appropriate sized electrode for the sinker and the size of the cutoff blade.
Before you spend the ~$50K i would develop a process with a local supplier. Then you would know what type of machine works for you application and what doesn't. This also helps to prevent you from purchasing a very expensive boat anchor.
RE: What kind of EDM should I use?
Repectfully
Kevin
Intelligent Design and Services. Inc.
www.IDandS.com
RE: What kind of EDM should I use?