Aluminum Headaches
Aluminum Headaches
(OP)
All,
We have an application where we are inserting an aluminum part into a plastic part. We are feeding the aluminum parts down a vibratory rail and using the part insertion plunger to gate the queued up aluminum parts. We are struggling with the build up of aluminum on the plunger. We have tried various things: carbide with a Titanium Nitrided coating, Tool steel with a Teflon impregnated coating, bare tool steel with a miror polish. None of these are getting us to the operational life we would like. Any other suggestions from my eng-tips.com compatriots would be appreciated.
Rich.......
We have an application where we are inserting an aluminum part into a plastic part. We are feeding the aluminum parts down a vibratory rail and using the part insertion plunger to gate the queued up aluminum parts. We are struggling with the build up of aluminum on the plunger. We have tried various things: carbide with a Titanium Nitrided coating, Tool steel with a Teflon impregnated coating, bare tool steel with a miror polish. None of these are getting us to the operational life we would like. Any other suggestions from my eng-tips.com compatriots would be appreciated.
Rich.......
Richard Nornhold, PE
http://www.personna.com





RE: Aluminum Headaches
Why is the aluminum building up at all? In order to get aluminum, you have to abrading it from the parts as they go by. And while aluminum is a relatively soft material compared to others, it's by no means that soft, particularly with Teflon coatings and mirror finishes.
TTFN
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RE: Aluminum Headaches
RE: Aluminum Headaches
We are using air to position them under the plunger and we have stack of them queued up behind the plunger. So you are getting stack pressure on the aluminum part and high cycles per minute on the equipment.
MiketheEngineer,
We are having the parts cleaned after they are stamped out. We get minor amounts of debris, but this isnt' what is causing the buildup of aluminum. The build up is from the part to plunger interaction as the plunger moves past and gates the next part to be put into position.
Rich......
Richard Nornhold, PE
http://www.personna.com
RE: Aluminum Headaches
Ted
RE: Aluminum Headaches
Bingo!
Rich.......
Richard Nornhold, PE
http://www.personna.com
RE: Aluminum Headaches
TTFN
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RE: Aluminum Headaches
About 500k or 2 weeks worth of runtime. Our goal would be 5-10 million cycles before we would have to tear down to clean.
Rich.....
Richard Nornhold, PE
http://www.personna.com
RE: Aluminum Headaches
TTFN
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RE: Aluminum Headaches
It causes the gated part to misfeed and then causes a jam in the plunger. This in turn causes downtime on the equipment.
Rich.....
Richard Nornhold, PE
http://www.personna.com
RE: Aluminum Headaches
Mike Halloran
Pembroke Pines, FL, USA
RE: Aluminum Headaches
> There ought to be a secondary gate, as Mike suggests
> Reduce the number of parts in the queue to reduce the pressure that's forcing the next part against the plunger
> Drill a set of holes in the plunger and push air out to keep the part from contacting the plunger
Is your vibratory rail possibly causing adjacent parts to rub against each other in the portion adjacent to the plunger, and then that residue gets transfered to the plunger?
TTFN
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RE: Aluminum Headaches
RE: Aluminum Headaches
RE: Aluminum Headaches
Stack with wax paper/oil paper/plastic sheet, use a vacuum to strip the top piece of paper as the plunger passes back to engage the next aluminum piece. Removes the one-contact-only surface, plunger side never contacts the aluminum.
Ted
RE: Aluminum Headaches
Have you looked at using an escapement to separate the queued part from the plunger?
Perhaps a small indexing wheel to pull a gap
Maybe a picture would help me, we do this stuff all the time.
Charlie
www.facsco.com
RE: Aluminum Headaches
RE: Aluminum Headaches
RE: Aluminum Headaches
Again, it was a swing.
There are days when I wake up feeling like the dumbest man on the planet, then there are days when I confirm it.
RE: Aluminum Headaches
So, you need to reduce the force pushing the stack of parts being fed from pushing down on the final two parts: the part being fed, and the one immediately above it. (You may actually need a "stack" of five or six parts to keep everything aligned, but you probably have 50 to 60 i the stack.)
So, reduce the height of the stack. Reduce or eliminate any spring pressure on the top of the stack. Increase the friction on the 2nd from bottom, 3rd from bottom, and 4th from bottom parts so they carry the weight of the parts above, not the last part and the part being pushed in by the plunger.