Have a new tumbler now need help with the media

Bought a nice used tumbler, 16in bowl vibrating type. It came with a mix of small media in it and I am testing it out. I have found that a flat aluminum plate will not stay under the media but keeps trying to float or surf on top. I will take some photos and post them soon to show you this. The blocks that I put in seem to be doing better but I am not sure why the larger plate wont stay down.

In my small tumbler I have been using the plastic triangle media that I bought on ebay, not sure the brand but it seems to work fine. Could it be that the stones are too heavy for the lighter aluminum parts? Anyone know a tumbling guru out there? I know if I call a vendor they want to know what brand I am using and then want me to send them a sample part. But of course as a job shop I never know what kind of part I am doing next so any ideas from those of you who have experimented with different media will be useful.

Charles

Photos coming soon.

Vibratory bowls don't get on well with large flat parts. As you found they simply float. Equally they will also stick together and clump up if thin and large enough. It does not just seam to be a grit size issue, but more a relation ship between media size and bowl diameter. i have only been around a couple of larger vibratory bowls, but IMHO bits like in your last pics just won't come out good. Smaller parts especially nearer cube or spherical always tumble in a hell of a lot less time. As soon as the parts start to get larger flat surfaces and the process just does not work anything like as well.

Charles


You can call Mikro: Mikro Industrial Finishing
Also, C&M Topline: Vibratory Finishing | Deburring Equipment & Machines | Tumbling Media

They won't care what brand you use and won't necessarily ask for a sample.
Keep in mind tough that there isn't a one size fits all solution for media, you likely will end up with a few different ones and will have to learn what works best with what material or shapes.
I've got 6 diff. types and switch them according to need.
Similarly, I have 4 tumblers ( small bowl, large bowl, rectangle tub and rotary ) and use the appropriate one.

Thank you Seymour, I only have a small one used for cartridge cases so this one is a good bit larger. I was trying for another even larger one but I only had the money for the one for now. I must say I do like this one, the coolant recirculates and it is nice and quite in the box the previous owner built for it. As for the media, all the tumblers he had had a mix of media in them, I will have to play with it some more and see what I can do with it. I think I will already try to sieve out the smaller size stones as they will get stuck in my counter-bores.

Charles

I do .063" X 1.5 X 4 aluminum plates and have given up on vibration units.
I found they work OK if you mix in some fine silica sand but I still had trouble with the dirt generated.

I use a smaller cheap cement mixer with the vanes made smaller and a ~50-50 mix of media and sand.
Use enough water so it not quite has liquid showing.

On my tub tumbler I've installed a larger pump and a regular household filter unit.
Also, I'm using a large 25 gallon tank for the water and it's a flow-through setup.
As for how to keep the parts pristine clean? Palmolive dish detergent as tumbling solution!
Foams up like a rabid dog, but the results are excellent.

Interesting idea, as a job shop I never know what is going to come in the door. I dont do enough of anything to buy a new machine but your idea sounds interesting. Thanks for sharing.

Charles

When i bought my 300db tub tumbler from c+m topline, the owner called me to discuse medias. He took the time to listen my needs, and suggested media/solution. They offer quite a few media/solution setups, and what he suggested has worked out great. Although i'm usually tumbling parts that require the same media/solution(So i don't have a need to make frequent changes in media type).

The light and flat parts tends to float on the surface of the vibratory finishing machine.
In real application we solve this issue by:
1. increase the motor power so that the tumbling will be more aggresive
2. We will use rotary barrel tumbler machine in stead.

Earnest