Overhead magnetic conveyor design considerations

[Jamison.Gates]

Hi all,

I am trying to figure out a design for a magnetized overhead conveyor that will transport ferrous manufactured parts from one conveyor to a set of conveyors that are perpendicular to the starting conveyor. The tricky part is that the magnetized overhead conveyor needs to be able to drop the parts at specific positions to land onto the perpendicular conveyors to then be moved on to the next manufacturing process. The magnets in the overhead conveyor need to be able to either de-magnetize or repel the part at specific intervals. There are two perpendicular conveyors acting parallel to each other, so the overhead conveyor needs to be able to drops the parts at multiple positions but at different times.

I have looked into using electro permanent magnets, but those are generally used for small applications. I have also been looking at programmable magnets or correlated magnets, but i'm not sure if those will fit the application. If anyone has any suggestions, please comment. Attached is a simplified sketch of the system that is trying to be achieved. Thank you!

[jboggs]

Believe it or not, years ago I designed a conveyor that did nearly the same thing. I used permanent magnet rollers (for which I learned the VERY HARD way that you MUST use stainless steel shafting) to transport stamped steel sheets from a press to a stacking station. To release the parts you don't have to "turn off" the magnets. All you have to do is separate your articles from them.

I did that with an array of pushrods, or fingers, positioned above the sheet flow path. They were linked together so that on signal they all extended downward simultaneously. If there was no release signal, the transported sheet would pass beneath the pushrods unaffected. Each sheet was supported by several magnetic rollers at any given time. The pushrods were arranged to insure separation from all the magnets simultaneously to keep the sheet from tilting. The pushrod array mechanism was actuated by a single cylinder. You could have such an array over each secondary conveyor.

[Jamison.Gates]

I hadn't thought of that pushrod idea. Thanks for the suggestion! I'm guessing they were pneumatically actuated, right?. I had been looking into the permanent magnetic roller idea, but I was seeing if there was some way to electrically disrupt the magnetic flux of a row of individual rollers with no luck though.

[Jamison.Gates]

Similarly, couldn't you also use permanent rollers for the majority of the conveyor, but use electromagnetic rollers on the section where the part will fall. Then you can remove the electrical current simultaneously causing the part to fall.

[jboggs]

I'm not aware of any electromagnetic rollers that will allow continuous rotation. Think of the slip rings and complications. Anyway, once the conveyed parts are just a very few millimeters away from the rollers they are out of the effective field.

Yes, the fingers were pneumatically actuated... but only use ONE cylinder. Tie all the fingers in a given area together with shafts and mechanical linkages. That's the only way to guarantee truly synchronized action. Synchronizing the operation of numerous pneumatic cylinders to operate reliably within a few milliseconds of each other reliably, every time, regardless of fluctuations in air supply and cleanliness is near impossible.

[Hudson]

If you can use pushrods, do you need the magnetics? Can you push the parts off of a conveyor perpendicular to your two target conveyors? Do you really want magnetized parts?