Vibratory Deburring and Polishing
This is easily done in a vibrating
tumbler or even a rotary style. You need some plastic media. I used media
from Grainger that was listed as:
Deburring Media, 3/8 Inch Styrene Triangles, 6 Pounds per
Box, For 6A898 and 6A899
This media was recommended
to me by a machinist friend largely because it was similar to what he
1" wedge shaped product from CandMTopline), but it was available
in smaller quantities more suited to my small vibrating tumbler:
tumbler was intended for polishing brass for reloaders, but they're all
pretty much the same...
I only needed
one package of the Grainger media to fill the tumbler. My tumbler was
intended for polishing brass for reloaders, but they're all pretty much
the same. I chose the one I have largely because it was available cheaply
on eBay, and because it had interchangeable "buckets" in case
I wanted to purchase more of them.
To use the tumbler
for deburring aluminum, fill the bucket with media, add water (I filled
mine just below the top of the media), just a little bit of liquid dishwashing
soap, put the parts in, turn it on, and walk away. I got a good result
after about 5 hours. Here are the parts before tumbling:
Lots of sharp
edges and tooling marks...
And here they
are afterward, along with a bit of the media:
And after the
deburr. Note the nice uniform finish. Tooling marks are all but gone...
The smaller the
tumbler, the more time will be needed to achieve the desired effect. In
this case, I got a nice even finish over all surfaces. It's best if you
can get media large enough that it won't even go into any holes, otherwise
it tends to get stuck in the holes and is a nuisance.
I did a whole
bunch of scrap parts in the one run. This process really does a nice job
replacing tooling marks with a satin finish. If there are gouges or other
deep impressions, it won't take those out. However, I did surface a piece
with a 3/16" endmill and it pretty well got rid of the tooling marks
This was done
with aluminum, which is pretty soft. Mild steel takes longer, and there
is some question about whether there's any point in even trying with stainless
Vibratory Polishing Tests...
I threw some parts I had in
the vibe and left them for 4 days with walnut shells impregnated with
green rouge. Here is what I got back:
You can see the polish best in the granite reflection of the edges...
On the left is
a part straight off the mill, covered with all sorts of tooling marks.
Unfortunately, the flash makes it hard to see when looked at face on.
It's hard to photograph these finishes!
Next up is the
part marked "deburred". It ran overnight with some deburring
media until it had a nice satin finish. There is definitely some grain
still on it. In fact, I had some parts that had the vibratory deburr and
some that didn't. The ones without were shiny with deep scratches left
from the tooling marks. I didn't bother photographing them as the satin
finish from the deburr looked better to my eye. Lastly, we have 3 parts
on the right that got a 4 day polish in the vibe. There is still some
grain visible, so I can't truthfully call it a "mirror", although
I notice a lot of people want to call any shiny part a "mirror".
But, they are quite shiny. You can see the bottom photo they are reflecting
the grain of the granite countertop they're sitting on. All in all it
is a nicer finish than the deburr. I suspect it would be nice to have
had some grade of abrasive in between the deburr and the polish. I'm not
sure what that would be, but there's still too much grain after deburr
for the polish to get it to a mirror.
I find when polishing
I often have the problem of moving to the next finer grade too soon, only
to have it do a wonderful job highlighting scratches that should have
been taken care of with the coarser grades. In any event, I am reasonably
happy with this first time polishing result. It looks like something you'd
buy commercially and think nothing of it. Best of all, I literally forgot
about it while the vibe did its work.
I need to experiment
a bit more on my exact processes, but I really like this approach. The
polished parts also picked up a wonderful smooth feel.