Carbide grade help

"Tom Gardner" wrote in news:IeCJg.4286$tU.3718 @newssvr21.news.prodigy.com:

Please do post the solution. That's where the real learnin' is.

Aha! .. Sorta like facing off in the lathe and going just a smidge past center. The carbide goes away instantly when it hits the steel going the other way and is being pulled? Glenn

Yep--on that order. It's going to be interesting to see what solves the riddle.

Harold

As much fun it is to have a problem to solve, the capacity of this machine is already sold and we are running 4 hours a day overtime on the other and through lunch and breaks. I'm in a pickle. Kind of a nice problem to have but if someone else, or the Chinese get attracted into flat wire, I'm screwed. The new machine will make me the largest flat wire producer in the world! (Kind of like being the largest producer of blue coffee cups with green and yellow stripes) But, it's my niche, and nobody else wants it.

PS. I need your advice on a grinding opperation, I'll gather the info.

Would it be possible to temper the wire post cut and run untempered wire instead?

Have you checked the wire to find if random places along length are over your specification for hardness?

Wes S

On Thu, 31 Aug 2006 18:48:16 -0700, with neither quill nor qualm, "Glenn" quickly quoth:

(Tom, here's a guide. These guys might help you decide what to use and give you tips on setup, clearances, etc. for your application.

Hey, Glenn, what are you doing talking shop, ya wannabe retiree? Get back to work. You have -one- full day left.

Well, the wire is immediately put into wood block brushes. Yes, we do run into hard and soft spots.

Ok, but what's fundamentally different about their operation? Something is different because they do not give similar results.

I build huge panel dies while my roommate builds smaller progressive dies. All the cutting operations are fundamentally the same, it's only a matter of scale.

In die work whatever can move, will move. Have you calculated the cutting force exerted by the moving insert?

What's the stationary inserts' seat/anvil material? I would use something like hardened 4140 or better. If the insert isn't sitting on a *very* flat surface (should be ground or very finely machined), it may only be sitting on two points, and it will be capable of rocking.

You can use some type of spotting blue to check if the inserts are sitting down, and where they're touching on their periphery. It sounds like the inserts are zero-clearance (straight sides). Was the insert nest cut using an endmill, or surface ground/wire EDMed? Again, the spotting blue will tell you what's touching, and it should be virtually the entire opposing side-face of the insert. This would be key.

Have you measured the flex in the arm to actually be zero during the cut?

I know all this sounds anal, but "the meticulous attention to detail" is probably what will uncover the problem. Something is likely sliding, flexing, rocking, etc.

Will your mechanism reliably cut one wire at a time?

Regards,

Robin

I was not poking fun at your deleima Tom. You and Harold just made a light bulb flicker for me. Unless it is something similar to what I have experienced on the lathe and some form of spring-back is allowing the two dies to rub together with the smouched piece of wire between causing more pulling friction on one block than the other I can't help and apologize for jumping into your thread. Glenn

Nope they kicked my ass to the curb at 1 PM today .. musta just missed you. Thanks for the sign on my freshly painted garage door LOL (door is to be replaced soon) Glenn

Well, now I've tried C-2 uncoated and the moving carbide cratered first. I've got more work to do.

Ohhhh! I see you've given me some work to do. I'm leaning with hope that it's a grade issue.

On Fri, 1 Sep 2006 18:02:13 -0700, with neither quill nor qualm, "Glenn" quickly quoth:

Yeah, we were there at about 12:20pm.

I thought that looked better than it had the last time I saw it. Yeah, I hope you're going with an insulated model to replace that 40 year old wooden monster. How long did it take you to figure out who put it up?

Hey, I aced my Oregon Contractor's License test. 75 out of 80 = 93.75% Now I engage my local insurance brokers for $100k liability and a $5k bond, pay the State $260, and I can hang out my shingle. Meanwhile, my web business is bursting with work. Never better. (Go figure. It was so dead that I had to pick some other way to make a living so I could afford another trip to GunnerLand(tm) some day.)

P.S: OTNick, I forgot to put the OT at the top. Sorry.

--------------------------------------------------------------- Never put off 'til tomorrow |

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What's that Lassie? You say that "Tom Gardner" fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Fri, 01 Sep 2006

So the other machine is cutting a flat wire with a _round_ hole? If that is the case, then I think that shows the problem. Can you angle the carbides so they don't contact the wire face all at once? Kind of like how a pair of sissors cuts paper at one point where the two edges cross. Perhaps you could grind a half circle where the wire makes contact.

Good luck.

P.S. Micro 100 is some of the best carbide I've used for making boring bars.

This may be of no use, but a thought.

Angle the arm insert at about 10 degrees. This will give a shearing action rather than cleaving.

Maybe someone knows what/how, it's done on coilers. They do square wire, and maybe flat, but mostly round.

It is quite possible that you already have thought of the following, but just to be sure, perhaps I'd remind you.

If it was you who constructed the machine I hope you were aware that the thicker the wire you are cutting, the greater the gap you must have between the sides of the edges. Look at common handheld shears for sheet metal. They are always made with a gap, if they are any good.

It has something to do with having the shear force (which always is slightly diagonal in real life because parts always have some elasticity) contained inside the wire and not allowing it to reach beyond the cutting edges themselves, which would mean that some shear force would be directed onto the flat part of the carbide edges. That might make them chip.

Bad:

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Those sound like streetsweeper bristles. I used to find these odd flat wires about 8 inch long on the streets in Michigan. Took me years to figure out that they are strret sweeper bristles. You never see the machines because they come at night.

As to cutting them it seems like having a miniscule wobble to the shearing action would be the way to go. The swinging arm doesn't just go straight up and down. it swings in for the cut and out on the downstroke so the blade doesn't drag. . Maybe not having a really sharp cutter would be an advantage in this case. Start out with it not perfectly sharp. Just imperceptibly rounded. You might get a micro burr but for a brush wire that large does that really matter?

That's an interesting concept, and one that was well tested and proven to be true. Might prove to be the solution----or not.

For those of you that have been in the shop long enough to remember negative rake carbide in it's infancy, one of the things that was recommended was to hand stone a small 45 degree chamfer, maybe .005", on the cutting edge of negative rake inserts. It prolonged useful life considerably--------and didn't have an adverse affect on the cutting action--which, for those that understand the theory of a false cutting edge, makes all kinds of sense. Needless to say, that makes an insert absolutely worthless for shallow cuts, but then negative rake isn't all that great in that application, anyway.

Harold

Funny you should say that, my TiN coating guy said the same.