Indexer motion for wire cutter 1

[lukin1977]

I posted this on Motion Control getting no replies so I am trying here.

I am designing a wire cutter mechanism
The mechanism consist in a 440mm shaft with a bearing support at each end. 25mm and 50mm diameter (see attached fie)
At one end there are bolted 4 cutter blades and at the other side there will be the mover

The cutter must spin and stop (indexer) at 4 dwell positions on every revolution. One ¼ rev every 0,375 seg so to achieve 160 cuts/min
Torque for each cut is 78,4 N.m

Please recommend a way of doing this

So far I was thinking about 2 alternatives

Alternative A: using a servo motor geared to the cutter shaft
Alternative B: using a rotary indexer activated by a constant input speed

 

[MikeHalloran]

It seems awfully complicated either way, and I don't understand why you need to stop/start the motion.

I suggest you examine a 'Little Joe' wire and tubing cutter.

Mike Halloran
Pembroke Pines, FL, USA

 

[lukin1977]

The big cylinder on the shaft has 4 U longitudinal grooves. The wire needs to enter the groove before it gets cut.
There is a stationary part that close the groove and holds the wire inside.
This is why the shaft needs to stop between cuts

See attached drawing

 

[lukin1977]

The end product is 350 mm straightened wire to be used in the production of welding electrodes

 

[Timelord]

There are designs around of Geneva Mechanisms that are easy to fabricate from cam followers and can easily handle your torque requirements.

Timelord

 

[lukin1977]

Geneva Mechanisms was my first choice too but I could not find any supplier

 

[MikeHalloran]

Here ya go:

https://precisionparts.wmberg.com/gearBoxes

I don't know what your torque requirements are, but it may not matter; I doubt that WNB knows their products' limits.

Mike Halloran
Pembroke Pines, FL, USA

 

[3DDave]

Are you looking for an off-the-shelf item? A would have expected that wire cutters would use a flying cutting head to cut the wire as it is being fed in a continuous motion.

Might see some ideas in thang's videos and pages.

https://www.youtube.com/user/thang010146/about

 

[lukin1977]

3DDave
The wire is fed continuously but it hits a stop to prepare the wire for the next cut. The wire is pulled from a wire coil through several grooved rollers (feed rollers) and there is a little slippage between wire and roller until it gets cutted. I Hope my explanation is understood

 

[MikeHalloran]

A former employer paid people to unroll refrigeration hose from huge spools, stretch it along a yardstick, and cut it to length. It was a mind-numbing job, and nobody liked doing it.

For ~$3500, we bought a machine that pulled the hose from the spool, measured a programmable length as it was pulling, cut it off, dropped the measured piece on the table, and stopped when it had reached a programmable count or ran out of hose.
You couldn't homebrew a similar machine for that kind of money if your labor is worth anything.

I'm pretty sure that similar machines exist that can cut steel wire. So search, already.


Mike Halloran
Pembroke Pines, FL, USA

 

[lukin1977]

The machines exist. We have the machine. I am just modifying the cutting mechanism because the actual design doesn't work well
Sorry, I did not clarify this earlier

 

[lukin1977]

I am talking with this company:

http://www.motiontechnique.com/rotodex-globoidal-cam-indexer.html