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Small size tumbling media

AgnewBlues

Plastic
Joined
Nov 14, 2021
Does anyone here have experience tumbling small parts, about 1” square and 1/32” thick? It is mostly 304 stainless with very small features like small slots machined in it.

The features are often smaller than 1/32”, and I’m wondering how small I should go with the tumbling media, to do a decent job deburring the edges.

I have no prior experience with tumblers. This will be my way of getting into this. One of my local suppliers insists that 3/8” triangle ceramic media in a rotary tumbler would be small enough to get to all the edges. I kind of doubt it, but this is the smallest media that this supplier has on offer. Other suppliers have 1/8” media and suggest that this would be the way to go. Ceramic triangles in all cases.

From what I have read, I understand that smaller media take a lot longer but are better at getting to small details, and also provide a better finish. Bigger media work faster but cannot get to very small features.

I am not looking for a shiny finish, but reasonably uniform and smooth. I really don’t mind how long it takes, as long as the parts come out looking good.

So how small should I go with the media? How small is small when it comes to tumbling?

It has been suggested to me that for flat parts, a rotary Tumbler would be best, because vibratory and centrifugal types tend to float flat parts on top of the media.

When I started running these parts, a little bit of sanding by hand was all that was needed for finishing, after machining. But the volume has increased and I cannot do it by hand anymore.

Any and all suggestions and advice welcome.


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Milland

Diamond
Joined
Jul 6, 2006
Location
Hillsboro, New Hampshire
Vibratory tumblers might be faster if the process is tuned right, but if no speed requirements a rotary might be easier to get results from. You can mix media, but it's a bit of a pain to sort media out if you decide you want to stay with one size after all. Use an appropriate soap solution to help keep the media clean, I've used regular Dawn detergent as well as more specialized compounds.

My larger (17" bowl, not huge) vibratory tumbler has a pump and settling bucket, which helps keep the bowl and media/parts cleaner IMO.
 

AgnewBlues

Plastic
Joined
Nov 14, 2021
You can mix media, but it's a bit of a pain to sort media out if you decide you want to stay with one size after all.

Is there a benefit to mixing media, instead of going to a smaller size? Is there a way to figure out what is the appropriate media size for the size of the part or the features on it? When mixing media, how do you choose the sizes of the smaller and larger ones?


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SeymourDumore

Diamond
Joined
Aug 2, 2005
Location
CT
Rotary tumblers are an order of magnitude slower than vibratory, and from my experience their primary benefit is nicer surface finishes ( even mirror if needed )
With that said, give these guys a call: Vibra Finish: Mikro Industrial Finishing Inc.


I have some small. 1/4" triangle for my rotary, as well as some 1/8 angle cut cylinder.
They both work for the right application in the rotary tumblers, but using them in a vibratory was quite pointless.

One thing to note about size: You either get media that is substantially smaller than your smallest closed feature, or just a tad larger,
otherwise you will either not get everything deburred completely, or worse, you'll be prying them little fu*kers out of the slots or holes.
 

AgnewBlues

Plastic
Joined
Nov 14, 2021
One thing to note about size: You either get media that is substantially smaller than your smallest closed feature, or just a tad larger,
otherwise you will either not get everything deburred completely, or worse, you'll be prying them little fu*kers out of the slots or holes.

Thanks for the link, looks interesting. Regarding size, the features on the parts are considerably smaller than the smallest size media anyone makes, so it will definitely be bigger media. That’ll save me the hassle of finding out how to pry them out.

I guess I’ll have to try a few different sizes and types and see what results I get. The media suppliers have different opinions on the matter. Ranging from half inch angle cut cylinders to 2 mm triangles. At least they all agree on ceramics.

In the long run, I will also be running aluminum and brass parts, but the first few large lots are all flat stainless parts. But all parts will be on the small side of tiny, with very small scale features. This is the nature of my work, for the foreseeable future at least.

So, for now I am mainly concerned about the media for the stainless parts.

Many thanks for the replies, guys!


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Milland

Diamond
Joined
Jul 6, 2006
Location
Hillsboro, New Hampshire
I'd try to keep metal types separate if possible, to avoid potential corrosion behavior between Al and other alloys. Ideally this means different bowls and media, but that may not be feasible from a space and cost standpoint. In that case, try to wash down the bowl and media before changing materials.
 

AgnewBlues

Plastic
Joined
Nov 14, 2021
I'd try to keep metal types separate if possible, to avoid potential corrosion behavior between Al and other alloys. Ideally this means different bowls and media, but that may not be feasible from a space and cost standpoint. In that case, try to wash down the bowl and media before changing materials.

I’m assuming I will most probably need to use different media for the different metals anyway, for best results, so I was thinking of different bowls to keep things moving faster.

How do you wash the media? Just doing a run with soap solution and no parts?


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Milland

Diamond
Joined
Jul 6, 2006
Location
Hillsboro, New Hampshire
How do you wash the media? Just doing a run with soap solution and no parts?

Something like that. It's also good to not just throw the effluent down the drain, a shallow settling pan will let the water evaporate off, then you can scrape the muck out into the trash. Setting aside the ecological/legal reasons, it prevents the debris from settling out and clogging pipes.
 

Pathogen

Hot Rolled
Joined
Oct 18, 2016
I use ss pins as tumbling media for coins

gun people use it for brass shell cleaning, check for the media there

pins are 0.045" dia and 0.25 long
 

AgnewBlues

Plastic
Joined
Nov 14, 2021
Something like that. It's also good to not just throw the effluent down the drain, a shallow settling pan will let the water evaporate off, then you can scrape the muck out into the trash. Setting aside the ecological/legal reasons, it prevents the debris from settling out and clogging pipes.

Very good points! Thank you!


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AgnewBlues

Plastic
Joined
Nov 14, 2021
I use ss pins as tumbling media for coins

gun people use it for brass shell cleaning, check for the media there

pins are 0.045" dia and 0.25 long

I was looking at these and the dimensions sound about right. But, is stainless on stainless a good idea? Coins and shells are not stainless, so it is dissimilar metals. Also, I am assuming that for coins and probably also for shells, the aim is not to remove any material, but to remove any gunk that is stuck on top of the metal. For deburring and breaking edges, you do need to remove at least a bit of metal.


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