mike93lx
ALLIANCE MEMBER
I believe this is research, not commercial. So I'd expect stuff like this testing and experimentation
Machining pure Tungsten?
- Thread starter no704
- Start date
RoninB4
Well-known member
-Multiples of anything should result in a lower price IF the second one avoids another machine set-up charge. With conventional EDM it could also mean less electrodes have to be made if a worn electrode from the first piece could be used for "roughing" the second piece. For that matter, perhaps some cash could be saved if you made the electrodes, you'll have to weigh the numbers for that.
mike93lx
ALLIANCE MEMBER
Is roughing done with EDM? I thought it was used for getting straight to finished surface
American Locomotive
Well-known member
You can do anything you want with an EDM! Quite a few shops use wire EDMs as glorified band-saws. It's convenient being able to clamp a bunch of stock in the machine and just have it carve off chunks all day on its own. Since the EDM typically leaves a better and more accurate surface than a band saw (to put it mildly), it saves you finishing time on the mill.
RoninB4
Well-known member
-There's two basic types of EDM (electrical discharge machine): Wire (WEDM) and conventional (RAM). For both the level of finish depends upon:
1) Tolerance required
2) Level/number of details
The following are generalized descriptions and not definitive or complete
Conventional EDM uses an electrode the size/shape of the blind cavity with any details machined into the electrode itself. The electrode can/will erode as it burns away the metal so sharp edges/details my become more rounded. Dimensions may change as the electrode burns and a taper may exist at the end of the burn cycle. If tight tolerances/details are required a second (or more) electrode may be required for a "finish" burn cycle. Sometimes details are selectively burned in with multiple "trodes" that are sectional to make things easier.
Wire EDM (WEDM) uses a spool of traveling wire instead of a hunk of graphite (or other materials) as an electrode. A small hole is created in the work, the wire is threaded through, and the burning process begins. WEDM is far more prevalent than conventional now but it must have the ability to go all the way through the work. All blind cavities are the realm of conventional EDM. Wire is capable of great accuracy and precision but even wire usually takes a rough and a finish pass to create that accuracy.
-Any of those ads showing nice looking parts from the WEDM are NOT how they look when they leave the machine stage. There's always a yellowish or brown (burned) surface to remove with the bead blaster and a small "***" to remove/blend with the surface grinder. Both types have a place and purpose.
rlitman
Well-known member
Correct me if I'm wrong, but what I've seen of the process, the spool works like a cloth typewriter ribbon, where it spools up on one side, then reverses and spools up on the other side.
I think it depends on the unit.
Been a few years since I've been in front of one, but I seem to recall ours spooled spent wire into an open bin.
It was of course tensioned through the cut, but from there just dumped into essentially a trash can.
I have no clue about machining. But I'm curious just how expensive? Tungsten electrodes for TIG are $20ish and that's really only a few ounces
American Locomotive
Well-known member
I'm not saying there aren't EDM's that do that, but every wire EDM machine I've seen (which is like 10, but they were all Fanucs, to be fair) throws the used wire in a big bin for disposal, as the diameter of the wire changes after it cuts.
RoninB4
Well-known member
-I'm not the last word on EDM either, it's one of the few machines I haven't run. I have been around and next to them since the late 80's, both conventional and wire.
They can either spool and take up on another spool or a chopper can be added which cuts the used wire at a predetermined length to go into a scrap bin. While it seems far more convenient to have a chopper it can affect the burning process. I was helping someone long distance figure out what was going wrong with his parts/programming, according to him the stroke of the chopper caused vibration to feed back to the part burn. We were stumped about the weird deviation in the burn path until he paused the chopper and the problem disappeared.
I've not been around EDM for several years and I'm certain that the technology and capability has vastly improved since I was around them on a regular basis. They've had the capability to orbit for at least a decade or two and who knows what else is current technology (pun unintended).
Right around $4k.
Holey Schmidt! I would never have imagine that a band saw could have cut it in any useful way. I am impressed!Well this is some miserable s#%*. After about 9 hours in the saw! Hopefully be thru it tomorrow. This will be going to the EDM shop for the remaining operations.
Only about $5k? I would have expected considerably more.
It did take about 11 hours and is like 0.125” out of square!
Yeah, but still, it's tungsten!
oldmachinenut
Well-known member
That’s how the Sodicks my son teaches on at the college operate
Ya, I knew it was going to **** going in. But not really how badly!
I thought you got through it pretty well.
Thanks I tried. And will Never attempt to machine it again. I had CBN tooling on my lathe and this stuff laughed at it!
RoninB4
Well-known member
-So there were some laughs to be had during machining after all?
Oh ya! Never seen CBN throw sparks before! Like max depth of cut 0.010” @ 400rpm. But that was in the little 13” Clausing. Probably should have used the 25” Mazac it only had brazed carbide for it.
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RoninB4
Well-known member
-That's part of the new video series "Adventures In Machining" by no 704.
RoninB4
Well-known member
-Brazed carbide is almost always (now days) a cheap grade of carbide with no matrix. Didn't used to be that way but unless it comes from a big name maker it's decidedly inferior to inserts. The popularity of inserts is why nobody bothers making good brazed bits any more. IIRC there were some decent ones made by Kennametal several years ago.
RoninB4
Well-known member
-The brazed carbide is acceptable for average materials. Not a lot of point to spending the cash for insert holders if not needed very often. I'd suggest a type of grinder for touching up the brazed carbide as more useful to you. Just a suggestion.
-Making fishing weights? Hope you wore PPE and did appropriate clean-up.
Ya all manual machines. Not really high speed spindles. Have a couple bench grinders with appropriate wheels. Green one for the carbide. Would love a surface grinder but don’t have a lot of need. Lead was turned at low speeds with lots of wd-40. Gloves for handling it and lots of hand washing! Lathe is still a mess. Have about 10 gallons of chips that need to be melted and poured in to ingots.
mike93lx
ALLIANCE MEMBER
But did you try 4000 rpm?
RoninB4
Well-known member
-That's a silicon carbide wheel and is ok for roughing (aside from the dust) but too coarse for all but reshaping the carbide. A diamond wheel is much slower but the cutting edge is far superior and leaves a better finish on the work.
-Wasn't suggesting a surface grinder, was suggesting a tool grinder like a Baldor 500 (expensive) or one of the clones. There's even a fairly low priced knock-off from Grizzly for a little over $300 that a diamond wheel could be added to. Link below.
Grizzly H7762 - Heavy-Duty Tool Grinder - Grizzly Industrial, Inc.
<h1>H7762 Heavy-Duty 1/2 HP Tool Grinder</h1> <h2>Take control of tool maintenance.</h2> <p>The H7762 delivers professional sharpening power to your workshop.</p> <p>The motor is 1/2 HP, 110V, single-phase, reversible, and 3450 RPM.</p> <p>The H7762 features dual 80-grit silicon-carbide grinding...
www.grizzly.com
-Smart precaution, lots of toxic material exposure doesn't show up for decades and by then it's too late.
-Or poured into a mold for a small lead hammer. They were popular years ago for "persuading" without marring the work. When they got deformed you just melted down and poured it for a new one. Often used for assembly or tapping down the work in a vise before milling.
That's pretty short-sighted.
Destroy a 4k chunk of tungsten, tools and waste days.
How was the quote laid out regarding material cost/liability? I wonder if it was really $2k plus the liability for the raw stock...
mike93lx
ALLIANCE MEMBER
Wonder if that is normal or a "we don't want to do this but will if you want it bad enough" quote
mike93lx
ALLIANCE MEMBER
Did you try convincing them of the opportunity for growth and all the clout they would get on garage journal?
Did you try convincing them of the opportunity for growth and all the clout they would get on garage journal?
Jokes aside I'll look at their capabilities tomorrow.
Always need new suppliers
If I was Neil I might have redacted my info though...
American Locomotive
Well-known member
Shop around? Seems like they're a pretty small operation. Surely there has got to be someone else in Arizona with an EDM.Doesn’t appear to have any liability included. Actually says not liable for customer supplied material.If it was $2k I would’ve been fine with that. Wish me luck!
Perhaps. Lots of wires around. Not many sinkers that I have found. And I have a buddy in the industry. But he is a wire operator.
Guy actually said that they could get it done in 1 week.