Aluminum Polishing with CNC mill?

[wwendorf]

This is a good thread and something I have been considering doing myself. I have a machine I am producing that is a modern version of an antique woodworking machine. The old antique machines were all jeweled. I want to do the jeweling on them as well. I haven't had a chance to experiment with it yet, but i've read a lot about the jeweling practice.

One interesting method was to glue a chunk of thick leather on a dowel and jewel with that and some polishing compound. I've also read of the pencil eraser trick.

I do like the idea of a dedicated jeweling (polishing) machine tho. That type of machine wouldn't have to be quite so accurate either.

Wade

[justgary]

wwendorf -

If I were planning to jewel large machine parts, I would want a pad much larger than a pencil eraser. The leather pad would work very well, and so would a big eraser that you cut and glue to a stick. For large parts, 1/2", 3/4", or even larger jewels would look good. I've even seen it done with a 4 1/2" grinder on very large sections of plate.

I'm pretty sure you can still buy valve lapping compound at your local auto parts store. Get a can of coarse grit and give it a try. Since you want a slow spindle speed, you aren't going to sling much gunk very far. It is very abrasive, though, so cleaning the machine afterward does make sense (just to make sure you didn't sling the gunk anywhere important).

Regards,

- Just Gary

[Doubleoh9]

Originally Posted by kevperro In terms of the vibrator tumbler. I've found the round ones, and some much more expensive square tub ones but nothing in my price range. I'd want to keep the cost down around $1000 and I need to put 16"-17" long parts in it. I've not found a solution in my price range. If someone knows of one, I'm all ears.

When I needed to debur some large tubes (11" long) I bought a cheap cement mixer from Harbor Freight, left the paddles out, and filled it with media, put a colander on the open end, tipped it to the side and turned it on. Works great for deburring larger stuff. Never tried polishing with it, but it would probably work.

[LeeWay]

I did a test with my mixer and lava rocks and only run it 10 minutes.
I could already see the burrs getting gone. I am designing my own right now. It will be the bottom of a plastic 55 gallon drum. Vibrator type.
We'll see how that goes.
For long parts, one guy on here built a trough style vibrator. Looked like it works pretty well. He has a video of it as well.

http://www.cnczone.com/forums/showthread.php?t=52143

[kevperro]

This looks like a viable commercial solution.

http://www.moore-tool.com/store/debu...ler-p-124.html

As much fun as a big DIY project sounds, I need to make parts and some money and just don't have the time to monkey with the experimentation needed. I want to plug it in, pour in media and throw my parts in there and go.

I just need to get them deburred and get the machining marks out so I can send them out for anodizing. Polishing MIGHT be something I try on just portions of the part. That was the reason I asked. I figured I could either bead blast the part, or vibratory tumble it and then move it back to the CNC machine to polish the portions of the part that will look real shiny. The contrast between a matt finish and the polished finish, covered with a clear anodizing treatment was the "look" I'm trying to achieve.

[Caprirs]

Originally Posted by Geof I am going to be contrary and say that it could be a workable idea, but I had better back that comment up otherwise Caprirs and Kipper are going to be all over me.

I respect my elders. I would never argue with them.

Having said that, when I worked for a machine tool builder, we had some customers who needed to replace ball screws, gibs, spindles, and coolant pumps due to excessive wear from abrasion. These were on big VMCs with box ways, flood coolant and 40mm diameter ballscrews. One customer used our machines for grinding ceramics and had to replace gibs and ball screws every few years. Another did nothing but G10 and replaced coolant pumps every couple months and ballscrews every 18 months. The coolant pump still worked but the seals would start to leak. The ballscrews still functioned but the precision deteriorated. The graphite machining industry has specially equipped machines to deal with the abrasive nature of graphite.

I should have qualified my too short answer by the ever-so-popular "it depends". If the machine were spending considerable time doing production polishing, I would bet serious money the precision of the machine would deteriorate rapidly requiring parts replacement within a year. For occasional use, some forethought into cleanup would go a long way towards minimizing potential long term damage.

From my point of view, I can pay someone else to polish a lot of parts for the cost of replacing my ballscrews.

[kevperro]

Well.... I bought this little guy. It don't expect a super polished look but it should at least get me most of the way there for anodized parts. The tub is 19.75" x 15.75" x 15.5" which won't hold a ton of parts, but should allow me to do 5-10 at a time.



I think I'm going to just try some manual buffing to get the polished look. If I get the parts most of the way there with the vibratory media, the final touch shouldn't take long with the right tools. At least it will be something to do while the Tormach is cutting parts.

[AMCjeepCJ]

I polish 400 series stainless and aluminum on my $70,000 VMC and quite honestly don't worry about it. My machine is plenty accurate and I use 4" diameter hook and loop pads to get a mirror finish on flat stock. I run coolant during my polishing operations and I figure most everything probably gets suspended in the coolant. Will it wear something out? Maybe... Am I overly concerned about it? Not at all... If it works and makes money, then it's worth it to me. Would I recommend it to others? Absolutely as long as they know it's always possible to end up with unexpected long term results when using something in a way it wasn't originally intended to be used...