Thread: Cutting with fine wire; thickness limits

Hi All:
I just got a RFQ for a wire job 8.25" tall and he wants me to cut it with 0.004" wire.
He's hoping for better than 0.0005" flatness too.
I told him he's dreaming.

My cutting condition tables go up to 30 mm thickness for 0.004" wire, and I've never run any on my new machine.
On the old Sodick it was the devil's very own to run 0.004" wire and I had no success with anything thicker than an inch, and even that was a nightmare from hell.

So my question is: what's the thickest steel you've successfully cut with 0.004" wire?
Cheers

Marcus
Implant Mechanix – Design & Innovation - home
Vancouver Wire EDM -- Wire EDM Machining

Originally Posted by implmex

Hi All:
I just got a RFQ for a wire job 8.25" tall and he wants me to cut it with 0.004" wire.
He's hoping for better than 0.0005" flatness too.
I told him he's dreaming.

My cutting condition tables go up to 30 mm thickness for 0.004" wire, and I've never run any on my new machine.
On the old Sodick it was the devil's very own to run 0.004" wire and I had no success with anything thicker than an inch, and even that was a nightmare from hell.

So my question is: what's the thickest steel you've successfully cut with 0.004" wire?
Cheers

Marcus
Implant Mechanix – Design & Innovation - home
Vancouver Wire EDM -- Wire EDM Machining

The inserts I have are made using either a 0.25mm or 0.15mm (0.01"/0.006") wire. A height of 2" isn't a problem for 0.15mm but it does take time. For an extra smooth finish 2 or 3 passes over the important contact surfaces add the final touch. What you customer wants seems impossible at least in the next few years. Has he ever known anyone that could do that?

Gordon
Flexible Measuring Systems

Marcus, I've tried .004" exactly once, and you pretty well surmised my experience with it. After getting the machine debugged & getting the cutting conditions worked out, the job turned into a retirement project time-wise. This was on ~1.25" parts. I could possibly see roughing out taller parts with .006" (or even .008"), then finish profiling it with .004", but I'm betting max height doing that would still wind up being in the 2"-2.5" neighborhood. Even then, flatness would be open to interpretation, at least with my machines. Is the customer needing inside corner radii at .002" max or inside profiles that are that small? At 8.25", I wouldn't touch it with anything less than .008".

P.S. I've read on this forum about guys using .002" down to .0008" wire . These fellas definitely have my respect.

Jim

There is a machine called the "Twin Wire" by AgiesCharmilles (formerly Charmilles Technology Corporation) that will allow automatic wire change, and threading, between larger and small diameter wires. It would help to automate a job with small internal corner radii. I do not recall if the Technology for .004 wire goes as tall as 8.25 inches. The company I work for does a lot of .0012 wire work, and some .0008 wire work, along with standard large diameter wire work. We routinely exceed workpiece height limits that are defined by AgiesCharmilles. It may be possible to produce the part your customer requires through a series of test cuts. Of course, almost anything is possible providing they are willing to pay for it. Best of luck with that. By the way, what is the workpiece material your RFQ requires?

Now I'm curious, so...

A few quick questions. If your customer requires a .0005 flatness surface, are they disregarding geometric control over non planar surfaces? I am just trying to wrap my mind around how they could inspect the part if the entire profile were critical. If they intended profile of a surface, then a vision system inspection, a CMM inspection, or producing an imprint of the cavity would not yield an accurate analysis of its geometry. Please consider all of this in the context of internal corner radii being less than, say .005 of an inch.

Marcus,

I don't believe that can be done.

As others have said: if the part could be roughed using .2mm or .25mm wire, and then the corners finished using .1mm..... well.... it's still not possible. (IMO)

I believe on a modern machine, around 50mm-60mm or so is probably a "realistic" upper limit for .1mm wire.

Can the inside corners that require such a tight radii be undercut, or anything like that?

PM

Thank you everyone for responding:
Well, the discussion began with a demand for me to sign an NDA, followed by a model of the desired part and a demand for the finished goods for this coming Monday morning. (The RFQ came in on Thursday afternoon).
I don't even have the wire guides for 0.004" wire yet, so it's a no-go.
It was supposed to be a mold insert for hand-pouring acrylic resin into.
It's been officially abandoned by me as unworkable.
He choked at the conditions I demanded to give it a try...I don't think he was really serious about getting it done and was looking to spend a hundred bucks or less.
I described for him, a way to split it into several parts and just mill the profile with a few form cutters and a couple of standard ball cutters.
Hands are washed of this job; I'm relieved not to be cutting it.
Cheers

Marcus
Implant Mechanix – Design & Innovation - home
Vancouver Wire EDM -- Wire EDM Machining

Turns out Charmilles machines standard technology (manufacturer qualified generator settings) only go up to 80 millimeters for 0.1 wire. They are conservative, so a 100 millimeter height may be achievable. Not enough to help in this case though.

Originally Posted by implmex

Thank you everyone for responding:
Well, the discussion began with a demand for me to sign an NDA, followed by a model of the desired part and a demand for the finished goods for this coming Monday morning. (The RFQ came in on Thursday afternoon).
I don't even have the wire guides for 0.004" wire yet, so it's a no-go.
It was supposed to be a mold insert for hand-pouring acrylic resin into.
It's been officially abandoned by me as unworkable.
He choked at the conditions I demanded to give it a try...I don't think he was really serious about getting it done and was looking to spend a hundred bucks or less.
I described for him, a way to split it into several parts and just mill the profile with a few form cutters and a couple of standard ball cutters.
Hands are washed of this job; I'm relieved not to be cutting it.
Cheers

Marcus
Implant Mechanix – Design & Innovation - home
Vancouver Wire EDM -- Wire EDM Machining

Sounds like a classic example of "Failure to plan on your part does not constitute an emergency on mine".

And 8" is way too thick for any realistic .004" machining. 2" is pushing it in most cases.

Happy 4th! (or to be more accurate, happy belated Canada Day!)