Wire EDM feeds sugestions

PegroProX440 · May 18, 2016

I am not the wire EDM guy, I am just someone who sees a problem with our current way of wiring. We have a through pocket we need wired that is 10.5 long by 1.00 wide with .375 radius in the corner. The plate is 4 inches thick p-20 tool steel. How long should this take to wire. Our guy said 40 hours and my jaw dropped, and I came here for help. What wire works good for this, what settings. We have a Mitsubishi wire less than 10 years old.

Zahnrad Kopf · May 18, 2016

PegroProX440 said:
I am not the wire EDM guy, I am just someone who sees a problem with our current way of wiring.

.

What kind of help do you think you need?

Is the current WEDM operator/programmer typically known as good at what he does?

If the answer is "yes", then combined with your quote above, my advice would be stay the fsck out of his way and do your own job.

If you really and truly believe he is so incorrect, grab the books and do the math. Your cut is approximately 92 Cubic Inches, depending on where the start hole is located. Of course, you do not state the surface finish required ( or even the one your WEDM guy planned for ) so we have no idea of whether this is a single rough cut or a 4 pass cut. ( one rough and three skims )

And you don't say if both top and bottom are flat or have height variations. Or if there is optimal flushing available at all times.

There are other concerns as well, but that should be enough to keep you busy for the morning.

You are welcome.

Now where is my coffee... ?

werkzeug · May 18, 2016

yeah, it can take a while to cut through 4 inches of p-20.
it would on the mits CX2(non-submersed) i once ran. Mitsubishi is not the greatest WEDM either. your wire brand depends on a lot. i used to use OKI . was prefered in my corner of the woods.
but the more you are 'helping' ,the more time i would add to those 40 hrs.

Mtndew · May 18, 2016

PegroProX440 said:
Our guy said 40 hours and my jaw dropped,

Curious as to how long were you expecting?

Matt@RFR · May 18, 2016

I'm no EDM guy at all, but this got me curious. This cut at 40 hours equals .0089 inches per minute. In general, is this about what you guys would run?

Zahnrad Kopf · May 18, 2016

Matt@RFR said:
I'm no EDM guy at all, but this got me curious. This cut at 40 hours equals .0089 inches per minute. In general, is this about what you guys would run?

Simply not enough information given to answer that with any manner of definitive response.

For example - Rough cut only? Rough and one skim? ( finish cut ) Rough and two skims? Rough and three skims? Surface finish? One may as well ask, "How much fuel economy will I experience driving from Miami, Florida to Portland, Oregon?"

Sybilsurf · May 18, 2016

Your wire guy is definately in the ball park. I would think that your wire guy would be happy to show you the Mitsubishi data sheets to back up his estimate. With good flushing and .010" wire he will rough cut around .030"/min which comes out to 13+ hours, and then the skims will run around 2 hours each time around. I would do 3 or 4 skims, depending on the tolerance. If you are sizing the pocket to a tenth, then add a couple of skims to size. If it needs to be straight to a tenth, add an extra skim, plus maybe a test cut on a piece of scrap which adds a couple of hours.

Ward

PegroProX440 · May 18, 2016

Thanks for the reply, it just seemed way long in my mind. He is pretty good at both the wire and sinker as in never making mistakes and blending in features well. On the other hand he is old school and not up to speed on any new equipment. Thats why I was wondering how far off base we are.

jmullett · May 18, 2016

Geez Zahnrad,

What's got your panties in a bunch? Are you the old school EDM guy he's talking about? :codger:

92 square inches is minimum 13 hours just for the rough and another minimum 9 hours in 3 skims of actual spark/burn time. It may also require additional stress relief cuts as well. Depending on the quality of the material and tight tolerances it could be many more hours. This doesn't take into account programming set-up and tank time lost due to wire breaks that occur during lights out machining.

Zahnrad Kopf · May 18, 2016

jmullett said:
Geez Zahnrad,
What's got your panties in a bunch? Are you the old school EDM guy he's talking about?
92 square inches is minimum 13 hours just for the rough and another minimum 9 hours in 3 skims of actual spark/burn time. It may also require additional stress relief cuts as well. Depending on the quality of the material and tight tolerances it could be many more hours. This doesn't take into account programming set-up and tank time lost due to wire breaks that occur during lights out machining.

LOL. Okay. I'll own that. Not bunched up. Was simply a matter of brevity for lack of time. Well, that and I really was needing coffee... :angry:

It is actually oft that people in physical presence of me take my brevity and directness for the quality of "asshole". Most of the time I'm just direct but yes, I am also an asshole.

This morning was just direct, though.

litlerob1 · May 18, 2016

Micro manager, thumbs down.

Robert

Mike1974 · May 19, 2016

info based on old Charmilles 290

Well to pile on here, I don't think that is a bad estimate without having any details. I think the absolute fastest roughing I ever got on our old Charmilles was about 17sq/hour. That was in 1" thick hardened (it does matter) material, .01" zinc coated half hard brass wire, top and bottom nozzles sealed perfectly. Throw in 4" thick material and your time goes up exponentially IMO. I burned a part that was 15" tall one time in our Charmilles 310, you don't know the definition of slow!

Red James · May 19, 2016

If 40 hours sounds too long, remember the machine will run just fine without someone watching it . . . in other words, 40 hours is less than two days. This help?

D Nelson · May 19, 2016

Mill it and be done with it

Sent from my iPhone using Tapatalk

TeachMePlease · May 21, 2016

D Nelson said:
Mill it and be done with it

Sent from my iPhone using Tapatalk

Seriously.. I don't understand, apparently. Why the hell are you not milling out 98% of the material and using the EDM to give you your finish dimensions? There's no reason to spend 40 hours wiring out something that you could spend an hour or two milling out, and an hour or two wiring out. I may be misunderstanding... But this sounds ridiculous.

Zahnrad Kopf · May 21, 2016

TeachMePlease said:
Seriously.. I don't understand, apparently.

This.

It is because doing what you describe will save you nothing. More oft than not, it causes trouble. WEDM _can_ work that way, but most of the time it likes for the wire to have material surrounding it. This creates a stable arc zone and also aids in flushing. Both are prerequisite for high accuracy as well as speed, believe it or not.

Go outside and grab your garden hose. Walk over to the corner of your house. Turn the hose on full blast and aim it at the edge of the corner of house.

What happened?

Yep.

It deflected away, shooting off to the side. Same thing happens in WEDM. This creates an area of instability for both the wire, and the arc, not to mention the flushing jet. So, things slow down to adjust for it. And it often leaves a shitty cut.

In the end, one still needs to get it clean enough and accurate enough to perform skim ( finishing ) cuts. So milling out the pocket saved you absolutely zero and more likely caused you time, effort, and grief.

I have seen wonderfully performing operations turned to shit because someone unfamiliar with the realities of the job thought that it was "too slow" to be correct and that surely, "...it can be improved upon and sped up."

WEDM takes time. It is a snail on thorazine. But it is a deadly accurate snail that can do things no other can.

I learned a long time ago to pay attention to the REAL things that affect speed and performance. Maintenance, consumables, and educated strategy. Don't cut corners. Don't pass "Go!" Do it right and collect much more than $200.00.

NAST555 · May 23, 2016

Zahnrad Kopf said:
This.

It is because doing what you describe will save you nothing. More oft than not, it causes trouble. WEDM _can_ work that way, but most of the time it likes for the wire to have material surrounding it. This creates a stable arc zone and also aids in flushing. Both are prerequisite for high accuracy as well as speed, believe it or not.

Go outside and grab your garden hose. Walk over to the corner of your house. Turn the hose on full blast and aim it at the edge of the corner of house.

What happened?

Yep.

It deflected away, shooting off to the side. Same thing happens in WEDM. This creates an area of instability for both the wire, and the arc, not to mention the flushing jet. So, things slow down to adjust for it. And it often leaves a shitty cut.

In the end, one still needs to get it clean enough and accurate enough to perform skim ( finishing ) cuts. So milling out the pocket saved you absolutely zero and more likely caused you time, effort, and grief.

I have seen wonderfully performing operations turned to shit because someone unfamiliar with the realities of the job thought that it was "too slow" to be correct and that surely, "...it can be improved upon and sped up."

WEDM takes time. It is a snail on thorazine. But it is a deadly accurate snail that can do things no other can.

I learned a long time ago to pay attention to the REAL things that affect speed and performance. Maintenance, consumables, and educated strategy. Don't cut corners. Don't pass "Go!" Do it right and collect much more than $200.00.

Thank you for this post! :cheers:

Since I am just getting into wire cutting I have experienced the same and thought that I was doing something wrong. I had a few dies to cut out so I thought that if I drill the biggest possible hole in the die plate and just skim cut the rest out it would make more sense :wrong:

I actually landed up screwing myself over even worse because of the flushing and arc aspects that you wrote about. Each corner of the shape had to have a magnet on so that they didn't drop out and short the wire out whereas if I had one solid slug to drop out if would have been way easier to hold it down. Instead of me just setting it up and letting the machine do all the work I had to bloody baby sit the thing every now and again. I have realised from that learning curve that I should just let the machine run and I walk away, especially now since I figured out the it auto power cuts with M02 and not M30. It sure is a snail,like you said,but cutting hardened dies and punches would never have been possible for me before I got the old Fanuc running.

Red James · May 23, 2016

I find it interesting that no one has commented on the op's feedrate question.

Wire edm's (for those who have no idea how they work) do not have a feed rate setting. The control feeds the wire as fast as it can and maintain a stable arc.

There is a MAXIMUM feed rate that is set when skim cutting to help control accuracy.

Mike1974 · May 23, 2016

Zahnrad Kopf said:
This.

It is because doing what you describe will save you nothing. More oft than not, it causes trouble. WEDM _can_ work that way, but most of the time it likes for the wire to have material surrounding it. This creates a stable arc zone and also aids in flushing. Both are prerequisite for high accuracy as well as speed, believe it or not.

Go outside and grab your garden hose. Walk over to the corner of your house. Turn the hose on full blast and aim it at the edge of the corner of house.

What happened?

Yep.

It deflected away, shooting off to the side. Same thing happens in WEDM. This creates an area of instability for both the wire, and the arc, not to mention the flushing jet. So, things slow down to adjust for it. And it often leaves a shitty cut.

In the end, one still needs to get it clean enough and accurate enough to perform skim ( finishing ) cuts. So milling out the pocket saved you absolutely zero and more likely caused you time, effort, and grief.

I have seen wonderfully performing operations turned to shit because someone unfamiliar with the realities of the job thought that it was "too slow" to be correct and that surely, "...it can be improved upon and sped up."

WEDM takes time. It is a snail on thorazine. But it is a deadly accurate snail that can do things no other can.

I learned a long time ago to pay attention to the REAL things that affect speed and performance. Maintenance, consumables, and educated strategy. Don't cut corners. Don't pass "Go!" Do it right and collect much more than $200.00.

I agree, just want to comment, that for certain small shapes it can make sense, but not always. The Charmilles machines I ran had a pocketing routine, it basically just ran the contour xx number (5-7-9) depending on material to remove, instead of the 'traditional' single pass for a rough cut. But again, it had limited applications, and 4" thick material is probably never one of them! The few times I used it was for over the weekend burning projects, put on fresh spool of wire and let it go to town. In the end it was slower with pocketing, but I did not have to pull slugs so the machine could rough, finish, cut wire, move to next hole/feature, etc all the while the shop was empty.

NAST555 · May 23, 2016

Red James said:
I find it interesting that no one has commented on the op's feedrate question.

Wire edm's (for those who have no idea how they work) do not have a feed rate setting. The control feeds the wire as fast as it can and maintain a stable arc.

There is a MAXIMUM feed rate that is set when skim cutting to help control accuracy.

If you have an old machine like mine then you do put a feedrate in

It does slow it down sometimes when the arc is struggling but most times when that happens I will get a wire break anyways. Best I've got the old girl to go is 1.4mm/min and that was on only 10mm thick plate.

Wire EDM feeds sugestions

Hot Rolled

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Aluminum

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Stainless

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