Dilemma: making a batch finishing process flow 1

[leanIE]

I've improved the flow of several drill/tap type machining operations, however, my latest problem (ah.........opportunity) is in the finishing process. All these machined castings have to be vibratory polished. Basically, this a glorified tumbling process (steel media and burnishing compounds). The cycles are usually 45 min. to an hour. This holds true for 80 parts or 20 parts (appx. 3" x 3" cubes)....doesn't matter. Any suggestions or insight that might help me improve flow?

 

[BML]

I have a few ideas ... just remember that batching can be lean if it is done properly.

#1. If the parts *must* be vibratory polished, then that operation will force your batch size to equal your transfer size (Nb=Nt). (This is assuming that you only put one part type into the hopper for any given cycle.) Given this, I would suggest that you make the batch sizes on your other equipment match this. However, the transfer size between each step (other than into or out of the hopper) should be driven down to 1.

#2. Why do the parts *have* to be vibratory polished? Is there a way to alter your other machining operations so that this operation is not needed? Or perhaps the specification is a bit of overkill?

#3. Can the parts be polished another way? For example, some wood finishing operations will use a "slap sander" instead of manual sanding to take the roughness out of parts before staining. Imagine a car wash with the spinning and draping bristles. You put a part on the line, which is moving at a constant speed, and X feet later the part comes out. If this works, this would drive your transfer size for polishing down to 1, but it may take up a lot of floor space and require some significant capital investment.

Hope this helps!