Which type of tumbler is better for Al?

[bob1112]

We are really trying to answer this question for our small production Al parts. We need to bring them off the VMC and hopefully run through a couple stages of tumbling to acheive a nice polish or near polish. Are the cam type box shakers better or faster or are the bowl types better? I think the bowls are quieter but what about the job they do?

Brandon

[Crash]

I like the bowl type better. We use rotating barrels and a vibratory bowl type. For a nice polished surface on aluminum, you will need to rough and finish tumble it. We use a plastic type of media for the rough tumbling. It leaves a soft, matte surface. It's a good surface to anodize. For a bright polished finish, ball burnishing is the best. We send a number of parts out for this process. There are some hard, ceramic media types that will put a nice finish on aluminum, but not as good as ball burnishing does. It approaches a hand buffed finish.

Good luck

[bob1112]

When you say ball burnishing, what type of ball are you talking about? The stainless balls? what size? Can walnut shell do it but take longer? I know the ball media is expensive so I would need to be sure of my purchase for sure. Thanks for the reply.

[Kevin Taylor]

Tub type I use work's great Noise is an issue but if it dosen't make noise it isn't going to doo anything for you plastic media leaves a good finish but if you have rough cut's ceramic first then fowellowed with plastic might be more to your licking Good Luck Kevin

[Crash]

Ball burnishing media is a small very hard, steel media. It lasts almost forever, but is very heavy. That's why we send our products out for this process. You would need a heavy duty machine for ball burnishing. You would also need to have a machine with a continuous flow of fresh soap and water to keep the parts clean. I think a vibratory bowl type would be best for this.

http://www.vibratoryfinishing.com/media.htm

[KOS]

for my anodizing I use a vibratory tumbler with the 1/4" plastic triangles to remove machine marks (i use the green ones), it will leave a matte finish. From here I then run it in walnut shells with rouge for about 36 hours. It brings the part to a very high shine. Since I want my anodized parts to look almost translucent I need to have a high polish before they go into the tanks...

[Stepper Monkey]

The plastic media is good, but for ball burnishing to a mirror polish shine I use ceramic balls. They have to be run wet (water with a couple drops of a special soaplike solution) to keep the black crap from clogging up thier microsurfaces but they work like nothing else.
I like the bowl systems for the pyramid plastic and the ceramic cutting media, as it is much fatser than tumbling. However, the ceramic balls are the opposite. I run three bowls in a row with descending order of cutting grits, followed by a rotary tumbler with the ceramic balls for a final mirror shine.

Only two caveats; The balls need to be broken in first - easy to do, just run them with some scrap for an afternoon. Second, the surface needs to be pretty smooth before the balls will shine them up - the balls don't actually remove much material, they just remove the matte finish, so make sure they are well vibro'ed down to a fine grit cutting media first.

[KOS]

hey stepper do the ceramic ball get in small areas? how big are they? The reason I go with the walnut shells is that they get in every nook and cranny.

thanks!

[Stepper Monkey]

The balls are 2mm for the smallest, so nearly everywhere anyway. They do like to get in every little slot and invariably on every piece a few want to stay wedged in a narrow slit or hole, so a dental pick to knock them out is always by the tumbler! Don't know if wlnut shell does the same.

[mxtras]

Can we get some folks to post some pics of the before/after, please? .

Include info on what media and what type of equipment and maybe some pics of the equipment and media, too.

Thanks!

Scott

[KOS]

they can get stuck in some very tight spots, just depending on how tight the area is...usually they dont get stuck at all...here is a sample shot no the best pick but you will get a good idea of what it can do.

please note that the middle pic says bead blasting although this one was put through the tumbler with the 1/4" green pyramids...

[KOS]

Hey Scott
Sorry I will have to take some pics of my set up and media for you, I only have an old shot of that part to post for now.... that is done with the set up i mentioned before...