Magnetic Clamp Design

[DayElBunger]

I have an application that requires "clamping" panels of corrugated aluminum in order to move them around with a robot.
The aluminum material is 0.5mm in thickness, corrugated to a panel thickness of between 6mm - 9mm (imagine square wave corrugated cardboard)
The panel size will vary, but will be on average 400mm x 400mm in size.

Initial thoughts involve the following process:
Place a "puck" into a recess - this puck could be magnetic or of any suggested material
Manually placing the panel on top of the puck
Robot will move to puck location and approach part until contact with top surface
Magnet activated - could be electro-magnet, but think that pneumatic approach of neodymium magnet would be stronger???
Robot will be able to lift part and move it through the rest of the process

Concerns:
Having enough clamping ability to hold part accurately while moving it
Not deforming the part due to clamping force - not sure this is really an issue
Ideally, a fairly hard urethane material (60-70 dur) would actually be in contact with the aluminum itself, adding stick-tion, preventing marking of surface, but unfortunately adding additional gap.

Questions:
Is an electo-magnet even a realistic option?
Would a magnet on both sides of the sandwich be the strongest?
Are multiple smaller magnets better than a single larger magnet - cogging effect, sorry for the terminology
Is there a configuration or sandwich of materials that would improve the performance?

Thanks for any advice or pointers.

 

[MagMike]

Interesting application!

Approximately how much weight is involved?
Do you have a maximum size limit on the diameter of the puck?

An electromagnet is possible, but I believe it'll be more cost effective to use a magnet to magnet configuration.

Multi-pole magnet configurations will maximize holding force, but the air gap from the urethane might cancel that out.

 

[DayElBunger]

Typical weight calculates to be approx. 3.5kg (7.5#)

The sizes will vary a lot, so we may end up with a couple of end of arm pucks, not ideal, but probably necessary.
For instance on a 400mm x 400mm part, we may want a larger puck for holding capacity as well as physical stability.
Smaller parts will necessitate a smaller puck, but will also weigh less and require less physical support.

I could see perhaps 1 puck at 50mm(2")for smaller parts and 1 puck at 100mm(4")for everything else?

Hopefully the design will be easily scalable.

 

[dgallup]

How are you going to release a permanent magnet?

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[EdStainless]

Your puck and gripper will need to match the contour of the corrugations.
I have seen similar devices that use a pulse from and electromagnet to release the PM holding magnet.
These take careful design so that you don't demag the holding magnet.
These will not be very large.
I'll try to sketch up a concept for you.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[prex]

With a PM you'll cause a shock, when the counter magnet or the iron grip approaches the PM, and this can damage your thin alu sheet.
Also the release part may be difficult to set up, unless you use a pulsed electromagnet as suggested above.
If you have already discarded the vacuum sucker approach and the mechanical clamp approach, then the electromagnetic clamp seems to me the way to go. In this case the electromagnet would be on the robot side and the puck would be an iron disc.

prex
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[MagBen]

the easiest, practical way i can see is to place a steel plate on the bottom of your panels, and a DC magnet in the robot. only when the DC magnet touches the top of panel, open the DC current to hold the steel. you can make the steel corrugated to decrease the "air" gap, if the force is not enough.