E46 OT Engineers, need yo help

Originally Posted by 217Bimmer

if you worked for me as an engineer, i would fire you in no time. wtf is this ****?!!

Rough! Maybe he's not a mechanical engineer.

Originally Posted by kuksul08

k2pilot that looks really cool, but I don't quite understand how it works. Is that just a section view? What's the angled piece at the bottom?

Yeah it's a section view. You said you wanted the wire to come in at an angle so I angled the feed tube.

The easy thing about the design is that much like what Scott is suggesting, you could have the drive motor from the blade timed to the wire feeding rate, it would work pretty much exactly like a camshaft, just replace a valve with these little guillotines and you'd have all the wires cut you need.

There's a million other ways to achieve this goal, and this one is by no means the best, just what came to mind.

Originally Posted by cowmoo32

New idea:

A rotating blade that sits as close to the plane the wire exits as possible. It would spin and shear the wire as it came out and it would be trivial to gear it to the same motor feeding the wire so they both run at the same speed.

You'd need to maintain tension on both ends of the wire in order for this to work otherwise the spinning blade just pushes the wire to the side.

That's only if OP has thin wire, I'm sure heavier gauge wire would be just fine with this method but it would be slow.

Originally Posted by 217Bimmer

if you worked for me as an engineer, i would fire you in no time. wtf is this ****?!!

Cause of confidentiality right?

Originally Posted by SamDoe1

The way I'd do it is to first of all use a double edge blade. They cut much better and don't leave the squeeze mark of single edge blades.

Second, how thick is the wire? Are we talking 58AWG (yes I have a machine that cuts this stuff at work even though it breaks if you look at it wrong) or 00AWG?

Third, use a cut bushing instead of a plate. I'll see if I can draw something up quick but the gist is use an EDM'ed slot for the blade to travel through. If you get the GEM razor blades, they are pretty good in terms of dimension accuracy in thickness, you can EDM a slot that's 0.001" wider than the blade and use that as your guide. This way, you aren't dulling your blade as it grinds on the surface and you aren't wearing your bushing by grinding a blade on it.

Fourth, use a short stroke pneumatic actuator to drive the blade forward and back. That should have no problem actuating at whatever speed you want. We have wire and tube cutters with this method that cut thousands of parts a day, all day, every day. Works great and has minimal maintenance.

Let me know if there's anything in detail I can help with. I have done a lot of work on wire cutting haha.

Interesting advice. What do you mean by a double edge blade? Like a safety razor blade? The wire I'm cutting is about 24-26AWG so it's on the small side but clearly not 58AWG

I can't quite visualize the cut bushing. Do you have any pictures of this stuff?

I'll definitely look into a short stroke pancake cylinder or something. I was trying to keep noise to a minimum since the other pneumatic machines in the area are very loud. The whole camshaft idea is great, but do I use a stepper and actuate it incrementally, or do I operate it continuously and use sensors to tell what position it's in. This whole part of the machine is pretty open ended at this point.

Originally Posted by kuksul08

and believe it or not those little xacto blades are very sharp and all the blades are very similar which is important when they're putting in 1-2 new blades every day.

They're sharp and dull very quickly

Do you have a better suggestion?

Originally Posted by kuksul08

Interesting advice. What do you mean by a double edge blade? Like a safety razor blade? The wire I'm cutting is about 24-26AWG so it's on the small side but clearly not 58AWG

I can't quite visualize the cut bushing. Do you have any pictures of this stuff?

I'll definitely look into a short stroke pancake cylinder or something. I was trying to keep noise to a minimum since the other pneumatic machines in the area are very loud. The whole camshaft idea is great, but do I use a stepper and actuate it incrementally, or do I operate it continuously and use sensors to tell what position it's in. This whole part of the machine is pretty open ended at this point.

While you can use double edge like a safety razor just fine (careful not to cut yourself) what I really meant was double bevel, sorry. Here's a picture:



As far as the bushing goes, here's a quick MS Paint I cooked up. The idea is that you support the wire on both sides as you cut across. The blade should be held at an angle so as to slice rather than crush. This will give you a better cut and made the blade last much longer. Obviously size the through hole for the wire according to it's size.

What are you going to be using to measure the length of the cut? Encoder wheel?

My concern with that is it would tend to smear the ends rather than cutting/shearing nicely. Leaving the chunk looking like this.

^ If your blade is kept sharp and cutting at an angle, you won't get those end defects like you drew up. The key is to support at both ends with as small a gap as possible and cut with a slice instead of a smash.

Originally Posted by v8 5

This is making me laugh

if you have to do it 4 times a second, thousands of times a day on an industrial scale, where on earth did the idea of an xacto blade holding up 500, 1000, 4000 precise /sharp cuts come up.

That's my first through, Have you ever used a razor blade? Think about how fast a shaving blade dulls cutting the hairs on your face, this is the same principle only the hair on your face is actually metal strands, surrounded by a rubber insulator. You'll be manually changing blades all day... UNLESS you also put a sharpening stone for the blade to rub up against as it comes back up.

I'm not an engineer.

EDM machine at work (and all others for that matter) have to dispose of the wire being used up in the machine as it cuts through the part.

When it exits the rear of the machine a set of spinning blades chops the thin wire into tiny pieces making it easier to dispose of/store.

I would imagine something like this would do the trick, just run the numbers to figure out RPM, rotor diameter, and wire feed speed.

The inserts are all replaceable as they wear as well.