removing the EDM off a die slot

[tvalen1432]

I'm sure there are several ways to remove the EDM other than the stoning it off. I was wondering if I were to sand blast it off, what material I could use that wont alter the size of the slot but will remove the EDM. Yes I realize by removing it it will affect a tenth or so. The EDM, as it gets removed by the punch seems to get almost gummy and I think with a clean slot to start I feel the punches and dies would last longer.
Any thoughts would be great!

Tvalen1432

 

[plastikdreams]

You are talking about recast...stones work well as does Emory paper. Fine grit glass bead will take it off but there's still polishing to do afterwards.

 

[SeymourDumore]

Honestly, I have not seen much difference in tool life.
With proper 3 or 4 cut strategy there will be no recast and very very small amount of HAZ ( heat affected zone ).
Though not an expert, but I have replaced ( re-made) conventionally machined dies/punches with EDM cut ones without noticeable difference.

 

[plastikdreams]

Reposted for some reason...

 

[tvalen1432]

Thank You all for your input. I tend to always look for ways that might improve my parts which in turn extends their life in production and this was one of them. They would prefer we didn't stone the slots for fear of altering the size so I reached for this alternative to explore.
Thanks,
Tvalen1432

 

[AD Design]

We always blasted the EDM residue off, not sure what we used. Care was always taken to have the cutting edge, whether punch or die section, downstream so there was less potential damage to the edge. Grinding sharp always followed. You might want to research the appropriate blast media or contact your local for choices. Removal/alteration of more than a tenth or two means the wrong media is being used. The WEDM guy should have already determined the burn correction factor a long time ago. JMO.

 

[tvalen1432]

"The WEDM guy should have already determined the burn correction factor a long time ago."

How do you figure the burn correction factor?
I believe that WEDM guy would be me at this point. Sometimes you don't know what you are doing wrong or if you are doing it wrong unless some one guides you. Or your drive to do better than what you are doing has you on forums such as this, picking the brains of those whom have more wisdom and experience on the matter. Which is what I am researching now.
When you say burn correction, what are you referring to exactly? Are you talking about the size of the slot before you remove the EDM residue, to the size after removal?
The way I was taught was to fit punch to size before removal, which I began to notice that after you put the punch in and out a few times, it produces a very different fit. Almost too loose I felt. (None the less, I continued as instructed to) That gap, I felt may be contributing to not fully cutting the material(plastic) after a while. Of course the die would need to be sharpened in time as well.

Thanks,
Tvalen1432

 

[AD Design]

Are you talking about the size of the slot before you remove the EDM residue, to the size after removal?

-Yes that's exactly what I meant. For about any machine I've ever bought or been introduced to I always wanted to know what it's capable of and what's the current condition. If that meant taking it for a test drive through all the gears, tramming the spindle/quill, and/or comparing "dialed" value to actual value that's what I did before risking a workpiece on an unverified procedure. Heck of a thing to have to tell the boss that the piece is now scrap because "I didn't check it before trying to use it".

I'm not the last word in accuracy and never ran a WEDM (you got that on me) but I worked for a second generation die maker that ran the WEDM to close tolerances. I asked him that same question about blasting the residue and the expected change in dimension. He told me that checking/verifying/recording the change BEFORE the money was on the line was SOP. He did that any time ANYTHING was changed or replaced to ensure a predicable burn. Also said that it should be verified as often as possible (post burn/blast feedback) as an alert to other conditions. That stuck with me throughout my time in the trade.

There are other, more experienced, members that can offer better advice than I can regarding WEDM (Marcus/Implemex comes to mind). I meant no slight or insult in my previous post, apologies if taken that way. I just thought working with tenths would almost demand a check sometime to verify what happens. I don't even trust a surface grinder to take tenths until I've checked temperatures, surface finish, wheel condition, and present size of the work before proceeding. I hate taking chances with expensive workpieces if I can help it. Your initial question was quite valid, my reply was poorly expressed. We ok now?

 

[Waakzaamheid]

As SeymourDumore said, if you are doing enough skims you really shouldn't be worrying about recast on a die. Maybe you need to just bump up the number of skims cuts, I'm not sure how many you are running currently. I've made literally hundreds of stamping dies over the years on WEDM and we would never blast them. I guess the exception would be a single pass cut punch that looks like crap off the machine but has like .010"/side clearance to the die so it didn't matter that we blasted it to make it look better.

 

[tvalen1432]

-Yes that's exactly what I meant. For about any machine I've ever bought or been introduced to I always wanted to know what it's capable of and what's the current condition. If that meant taking it for a test drive through all the gears, tramming the spindle/quill, and/or comparing "dialed" value to actual value that's what I did before risking a workpiece on an unverified procedure. Heck of a thing to have to tell the boss that the piece is now scrap because "I didn't check it before trying to use it".

I'm not the last word in accuracy and never ran a WEDM (you got that on me) but I worked for a second generation die maker that ran the WEDM to close tolerances. I asked him that same question about blasting the residue and the expected change in dimension. He told me that checking/verifying/recording the change BEFORE the money was on the line was SOP. He did that any time ANYTHING was changed or replaced to ensure a predicable burn. Also said that it should be verified as often as possible (post burn/blast feedback) as an alert to other conditions. That stuck with me throughout my time in the trade.

There are other, more experienced, members that can offer better advice than I can regarding WEDM (Marcus/Implemex comes to mind). I meant no slight or insult in my previous post, apologies if taken that way. I just thought working with tenths would almost demand a check sometime to verify what happens. I don't even trust a surface grinder to take tenths until I've checked temperatures, surface finish, wheel condition, and present size of the work before proceeding. I hate taking chances with expensive workpieces if I can help it. Your initial question was quite valid, my reply was poorly expressed. We ok now?

Wdevine, we are definitely good. No offense taken. To be honest, I sometimes tend to over think things at times. That's not always a bad thing. One could be doing something a certain way for a long time and then all of a sudden learn it hasn't been the best way or right way. Or some one found a better way along the way. I do try to strive to make sure I am producing the best possible parts for the company and am always trying to learn something new when ever possible.
Our Supervisor whom is a mold maker has recently retired so all we have left is a long time mold maker co worker whom is constantly saying, "I know it can be done because these old guys used to do it with old machines." But of course has no knowledge of working the EDM. I tell him "That's great! Can you bring them in to come teach me then?" I only have 8 years with EDM and I know a lot more than I give myself credit for but I know there is soooooo much more to learn. Plus, a year ago we were blessed with an MV2400S to go along with our little FX10 we have. That has been it's own adventure in capabilities.
Yes Marcus always has good input! I value the guidance and support from all whom participate in this forum. (Also Mitsubishi of whom I have on speed dial and are always there when needed.)

Thanks,
Tvalen1432

 

[tvalen1432]

We have never blasted the dies before. I think I seen one around once but never seen it used. So that is all new to me.

 

[AD Design]

Wdevine, we are definitely good.

-Glad we're ok, difficult sometimes to determine context, or intent over the internet.

As others have posted it's not critical to blast recast off for some things (punch/die section) that will likely get wiped off during intended use. Some things it can make a difference. Sometimes the design called for an oddly shaped punch in a punch holder or a keyed die section where grinding in was either impractical or excessively expensive. Some times an engineering change or a destroyed die section needed to burned in. Fitment became important on stamping dies that didn't have much for die clearance to begin with. Perhaps taking more skim cuts would have made it unnecessary (I wouldn't know) but Mike knew what to expect beforehand through testing. The few times I made WEDM fitment for him like this it was the difference between a tight/press fit and a light tap fit with before/after blasting. At the time it seemed like something else to increase the capability/expectations for the shop. What others do now with more modern WEDM is beyond my knowledge. Perhaps others will chime in.

 

[TXEDM99]

We use #10 glass beads for blasting. We were hand polishing to a mirror finish and this has made no difference to the end product