Sinker EDM Tolerances???

vtcnc

vtcnc

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Anybody on here have in depth experience with sinkers?

If so, what are the best tolerances achievable with the technology? I’m looking for something to substitute surface grinding a profile that requires flatness and straightness between .001-.0005”

If not achievable with sinkers, any suggestions?

Bryan (vtcnc)


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Bryan , we have sinkers here in the other shop . We do a lot of die making , tool making etc . Our "expert" just left for the day and will be back on Monday . Do you have a specific question or job application I should inquire about ? I may run into this guy tomorrow up another shop , and I could ask .
 
The Mitsubishi sinkers that I ran in a previous life (many years ago) could easily hold tolerances of a few thousandths of a millimeter.

.0005" would be easy...

-Bear
 
Here is a representative example of what I'm talking about:

The required accuracy is due to the fact that there is a mirror image of this die insert section - forming a "V". The apex of the "V" is critical to forming good parts. Also, if one die is more than .0005" higher or lower than the other, we tend to start to see longevity problems in our stamping runs.

The overall size of the part is about 1-1/2" long, 1/2" wide and 5/8" tall. The angled profile is something like less than 1/8" high off the face, and has radii that are not full depth but are constant radius.

View attachment Knife Edge Die_Large.mp4
 
In my former life in aerospace we had suppliers providing aluminum parts to +/- .0005 by plunge EDM.
 
Thank you everybody for the input and what I'm taking as reassurance that we aren't crazy thinking these tolerances are a possibility using some alternative machining method. We are going to further explore this and see if we can find a used plunger/sinker and get somewhere with this.

Currently, dressing the wheels, setup and grinding these profiles is about 50 hours per run for about a dozen pairs (lefts and rights). Do you think a sinker will make it easier and a little faster to run while holding the tight tolerances? While I know that is a loaded question for tool & die machinists, I'm just trying to gage whether I'm crazy for suggesting so or not. My impression is that because these profiles are not that complicated and deep, run times won't be too long. Thoughts?
 
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