Teach me about tumblers.....

moonlight machine · Apr 26, 2020

I have a Burr King 200 I use it a few times a year. Usually for small 4130 parts, 1/8" x 1" x 2" or so mostly in lots of 50. Sometimes water jetted / laser cut or just cut out on the mill. I just want to blunt the sharp edges, no big expectations. The media is from vibra finish, ceramic media, shape ACTS, looks like a triangle. Type SF size 5/8 x 1/4 2 issues, it takes a day or more to break the edges and all the pieces tend to migrate together and stick together, usually 5 to 8 pieces. is this normal?

jz79 · Apr 26, 2020

a customer of mine had the same problem with aluminum parts in larger round tumbler, about 1m in diameter, they usually run ~80 parts in 8x15x140mm flat pieces with some holes in them, and they tend to stick together sometimes sometimes more than 2 pieces, they ended up running a small zip tie through one of the holes, loose loop, so media can get "under" it, that solved the problem with that particular shape

they run them with media and water+compound all to tumbler manufacturers recommendations, they still stuck together

they also run similar sized stainless laser cut parts with different media, different additive to the water, same problem, same fix

manufacturer suggested running less parts, that didn't help, some still stuck together and the reduced productivity was a not acceptable either

edit: regarding aluminum parts, they also run around 25x80x25mm shaped parts with 2 25x80mm flat faces, and those don't stick together any more
maybe size of the media might have helped them, but buying all sorts of different media just for testing would get expensive quickly for that size tumbler, the tumbler itself was nearly 9k EUR

thermite · Apr 26, 2020

moonlight machine said:
I have a Burr King 200 I use it a few times a year. Usually for small 4130 parts, 1/8" x 1" x 2" or so mostly in lots of 50. Sometimes water jetted / laser cut or just cut out on the mill. I just want to blunt the sharp edges, no big expectations. The media is from vibra finish, ceramic media, shape ACTS, looks like a triangle. Type SF size 5/8 x 1/4 2 issues, it takes a day or more to break the edges and all the pieces tend to migrate together and stick together, usually 5 to 8 pieces. is this normal?

Gots IRON in that alloy. Check for magnetism building up. It don't take much atall.

No Iron is easier.

Ran hundreds a day of 14K and 18K gold - rings mostly - for ten years, tumbled overnight the next step after sprue cutting and filing-off the stub.

Never had the problem of clumping. Had a seasoned expert shop foreman who'd been at it for ages. Only thing I recall asking him about it was why he always used TWO media.

One did all the work. The other did nuthin' but improve the spacing-out distribution of the parts, reduce the count of hits and the amount of force back of it of 'em hitting each OTHER 'stead of the media.

Took longer, but overnight was plenty. Or less-than ALL night, as he had the tumblers on a timer.

The results were more uniform as well. Fewer fine dings, smoother finish all-over. So we saved on hand polishing time and cost - our next step before setting the stones and final polish.

Worth a try? Experiment on "drops". Take notes.

Onct yah get it "right" there's no need to sit and watch it, after all. Apply yer proven "recipe", set the timer and go make sumthin' else.

If is IS magnetism, cheaper to go over to a faster method. Buffing wheel hit on the edges, perhaps?

neilho · Apr 26, 2020

moonlight machine said:
I have a Burr King 200....I just want to blunt the sharp edges, no big expectations. .... it takes a day or more to break the edges and all the pieces tend to migrate together and stick together, usually 5 to 8 pieces. is this normal?

I assume wet process - sticking together is common. Flat meets flat, stuck. Frequent checking and separating can help, as does fewer parts per load. If you can put a screw/nut through/into the part, the head/nut can help separate parts, too. Plastic screws preferred. If using metal, a good locking device is essential. DAMHIKT.

A day seems like way too long. My experience is with aluminum in Swecos (larger bowl type tumblers), none with tumbling steel or Burr King table top units, but I expect edges to be deburred in an hour or so. Surface finish takes longer, depending on the starting point.

FWIW, parts migrating together is a function mostly of the type of tumbler, and some to do with getting the process right. Denser media would shorten cycle time.

Some questions, being a question guy

....Is this a flow through process? How often are you dosing the mix? With what?

moonlight machine · Apr 26, 2020

neilho said:
I assume wet process - sticking together is common. Flat meets flat, stuck. Frequent checking and separating can help, as does fewer parts per load. If you can put a screw/nut through/into the part, the head/nut can help separate parts, too. Plastic screws preferred. If using metal, a good locking device is essential. DAMHIKT.

A day seems like way too long. My experience is with aluminum in Swecos (larger bowl type tumblers), none with tumbling steel or Burr King table top units, but I expect edges to be deburred in an hour or so. Surface finish takes longer, depending on the starting point.

FWIW, parts migrating together is a function mostly of the type of tumbler, and some to do with getting the process right. Denser media would shorten cycle time.

Some questions, being a question guy ....Is this a flow through process? How often are you dosing the mix? With what?

Not flow through, I dump the bowl in a screen basket and wash the media with a garden hose and rinse out the bowl after about 5 runs. Burr king additive. I hear some people use dish soap, how does that work?

gustafson · Apr 26, 2020

Fewer parts, maybe

walk over and break up the part clusters every once in a while

Pondering if more aggressive media for shorter run times would help

I have used all sorts of soap for my aluminum parts over the years, finally back to the tumbler specific stuff

Maybe try more water

At the end of the day the problem does not disappear, but in my case it does not affect the edge deburring, so I break them up a bit before removal so the surface gets an even finish.

I run a 3 foot dia unit, also have medium tub, used to have a big round.

If you an see forward to using a big one for more different parts, get one, you won't be sorry

Guest · Apr 26, 2020

Seems like with round vibratory tumblers you have to get everything just right or things progress real slowly. I just either use dish soap or simple green mixed with water when I wet tumble. I think if I were in your shoes I would try putting some small headed tacks in the batch,or small finishing nails. I bet if you dry tumble with aluminum oxide they won't stick, but that is a slow process for heavy burrs and will leave a matte finish that if unwanted will take more processes to get rid of.

moonlight machine · Apr 26, 2020

Dualkit said:
Seems like with round vibratory tumblers you have to get everything just right or things progress real slowly. I just either use dish soap or simple green mixed with water when I wet tumble. I think if I were in your shoes I would try putting some small headed tacks in the batch,or small finishing nails. I bet if you dry tumble with aluminum oxide they won't stick, but that is a slow process for heavy burrs and will leave a matte finish that if unwanted will take more processes to get rid of.

I raised the water level and that helped a lot. Less sticking together and faster as well.

TDegenhart · Apr 26, 2020

Common problem. Many design books recommend adding a feature to prevent interlocking if possible.

Tom

Garwood · Apr 26, 2020

I run my aluminum parts through vibratory tub tumblers with ceramic media, but my small steel parts I run through a wet rotary tumbler. Instead of 10 hours to knock the edges down the rotary tumbler does 60rc parts in 15 minutes with hard steel shot. It tumbles wet with solvent to keep dust down and parts clean.

DDoug · Apr 26, 2020

HF mini cement mixer and a Home Depot 40 lb bag of white limestone chips.....

Take the impellers out (or don't put them in when you assemble it out of the box)

thermite · Apr 27, 2020

digger doug said:
HF mini cement mixer and a Home Depot 40 lb bag of white limestone chips.....

Take the impellers out (or don't put them in when you assemble it out of the box)

Surely... wrap it in shipping shrink film as well.

Neat part is about two hours in yah can watch the work progressing through the holes worn in the drum?

neilho · Apr 27, 2020

moonlight machine said:
Not flow through, I dump the bowl in a screen basket and wash the media with a garden hose and rinse out the bowl after about 5 runs. Burr king additive. I hear some people use dish soap, how does that work?

Soap and water wash the stones to keep them clean enough to abrade the part. The ratio is adjusted so the media is clean, but with just enough foam to lift the "dirt". It's tricky, because everybody's water is different. My soft water foams easily, so non-chlorinated dishwasher detergent keeps the foam down and supplies some cleaning power. Hard water generates less foam so dish soap could work well. I've heard Dawn works for some people but have no experience with it.

The degree of oil or scale on the parts is another variable. Lots of 'em with this process.

Burr king additive.

Was looking at the Burr King site - there seem to be a few. And they recommend something called "crystal beads" to keep the parts separated.

Bolting the tumbler to something massive, like a yard of concrete, will help. The machine then moves the mix, not the base of the machine. A denser media is more aggressive, as are pointier shapes. A full bowl helps too.

Burr King also gives out advice. A lot of media vendors run vibratory shops, and will develop the process for you, maybe even pay a site visit and quote doing it for you.

A day is way too long for just knocking the edges off- an hour sounds better!

DDoug · Apr 27, 2020

thermite said:
Surely... wrap it in shipping shrink film as well.

Neat part is about two hours in yah can watch the work progressing through the holes worn in the drum?

No joke here.

I did this on arooneeum parts.

FWIW a 5 gallon bucket lid is a perfect fit to cover the open end of the mixer, the holes for the ribs (not installed) are perfectly placed for some 1/4-20 eyebolts (on the outside) to bungee the lid in place.

This lid enables you to angle the mixer far more "downward" for more aggressive cutting.

Also with the ribs out, there is much less parts hitting parts damage.

jz79 · Apr 27, 2020

there are those polyurethane spray on liner systems they use to protect truck beds, that might be useful to prolong the life of the barrel, but there might be issues with the drive, some even have plastic gears, which is fine for occasional cement mixing, but not for 8h/day or more of continuous use

DDoug · Apr 27, 2020

jz79 said:
there are those polyurethane spray on liner systems they use to protect truck beds, that might be useful to prolong the life of the barrel, but there might be issues with the drive, some even have plastic gears, which is fine for occasional cement mixing, but not for 8h/day or more of continuous use

Why would you want to extend the life of the drum if the plastic gears won't last any longer ?

And why mess with lining that cost's more than just buying another mixer ?

And WHO said anything about "8 hours runtime" ?

IF the OP ends up doing MORE work of this nature, they can BUY a PROPER
PROFESSIONALY made vibe bowl.

jz79 · Apr 27, 2020

I'm not criticizing the cement mixer idea, I'm just saying that if you want your 200-400 mixer investment to last longer, look into the cost for the liner and avoid mixers with plastic gears, no need to get all capital letters on me :P

there is another problem with round rotating tumblers, the media/parts mix may tend to slide on the polished down bowl instead of rolling over and making the top portion slide - which is the actual motion required for this to work, you need some friction between the bowl and the mix, that is where the liner can help, or some other type of plastic screw in ribs

Limy Sami · Apr 27, 2020

Try what we call type 1 granite chippings (that we resurface roads with & dirt cheap from a quarry ) and run them dry.

DDoug · Apr 27, 2020

Limy Sami said:
Try what we call type 1 granite chippings (that we resurface roads with & dirt cheap from a quarry ) and run them dry.

Yup, I used limestone (what I had) and because it is more friable, went up size to 1b-2b stone.

Guest · Apr 27, 2020

What I want to know is why did the rotary tumbling barrel with the screw on lid go the way of the dinosaur? Some of the lid assemblies are a PITA to deal with. I was doing some experimenting in a small rotary. I tried some kerosene and it caused the barrel to deform and the 4 piece lid system popped off. Nice mess!

Teach me about tumblers.....

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