o/t Aluminum finishing / Cleaning

[Chris Rizzo]

So my sales guy is gripping that the parts are getting all "nicked up" and "oily filmy"...

 

They all get r-5 annodized, but he's all a$$ed up about watermarks, coolant goo, etc. not coming off in the brite-dip...

 

I tell him "Sell some part that don't require EIGHT differnt flips, and maybe there'd be fewer scraches.

 

Anyhow, my question is:

 

Do you guys have any rinsing procedure for cleaning? Magic concoctions, other than Jack and Cokes? Any ideas to keep surface scratches to a minimum? I consider myself pretty darn careful, but you so much breath on 6061 and it's scratched...let alone flip it 8 times.

 

[crazy^millman]

Tape the surface and then Bondo it. Mihgt look at a more frindley coolant to aluminum. Might look at cardboard eggcartons for swapping the parts and might look at makign softjaws out of delrin for some of the operation. I have also made sure that the parts get sprayed with wd-40 right after coming off the machine seem to limit the staining from coolant on some materials. Might look at seeing if you did the parts in a 4th axis would limit 8 handlings to 2 or 3 might help also. I have even put rubber down on the table of the machine as well as the table tops where you place parts or even foam on the table tops. Yeah sucks but military parts will get rejected for such things as well as medical parts I made in the past and some of the clear acrlylic parts we make now have to be perfect we even wear glove ot keep off finger prints for final boxing up. One other trick is platic bag to put parts in helps keep nicks down also.

 

HTH

 

Oh yeah congrats on the Senior membership.

[chris m]

Dependng on part size, surface finish requirements, and tolerances a Sweco or other vibratory bowl with the right media can hide a lot of nicks and give a nice uniform surface prior to plating. Glass bead is also a possibility for this. Ron is on the money with the plastic jaws and such if you can get away with it. If you need steel jaws they sell a pretty rugged plastic film for use in sheetmetal bending applications to minimize die marks that might be applicable.

 

I always try to do as much deburring and chamfering as humanly possible in the CNC machine to minimize manual deburring because that is always f__king parts up [oops, slipped and gouged the whole face....oh well]

 

C

[Rekd™]

Try keeping alum with silver plating clean. No coolant, but still get spindle oil on 'em. PITA.

 

I'm with Chris, If I can cut an edge, I deburr it on the machine. I leave the surfaces shiny, no scotch bright. Make damn sure your jaws don't have crap in them, (ANY crap will make marks in 6061), keep the parts in those egg-crates or similar setup to seperate the parts from each other. Even wrap them in foam packaging between loads. Place them on a rag or something soft, besides wood/formica/steel benches. Wipe the jaws/fixture, keep the crap off it. Don't let people handle them. Don't let QC touch them. Keep all crap out of the jaws. I could go on, but I'm past meh 2 minute window of "typing concentration", let alone thinking of ways to keep parts from getting scratched...

[Chris Rizzo]

quote:

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Don't let people handle them. Don't let QC touch them.

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I have a feeling that's where some of my problems are coming from!

 

Also love when someone sets down a piece of emory cloth on my bench...there it goes, totally contaminated.

 

I've got a completly foam & rubber lined staging area, however most of my jigs and fixture plates are also 6061. When stuff is clamped tite to a fixture plate, even unused holes are printing a bit! (Yes, the are TOTALLY burr free). Gotta keep parts clamped tite-tite when running the highfeed at near-stall capacity. I'm going to look into some plasic lining material, though.

 

Unfortunatly I'm machining the finished faces in the first ops..great referance planes, but they only get damaged during the other ops.

 

Also wondering if we've got hard water in the building....like the wd-40 idea, Ron.

 

thanks for all the input, fellas.

[Rekd™]

cmr, the plastic lining might be a good idea. Also, depending on the part/tolerance, you might be able to leave a .002" skin on the locating faces to clean up as a last op in a controlled environment, (i.e. no holes in fixtureing where it touches parts etc.)

 

Also consider taping the parts, (again, tolerance permitting), or taping the fixturing, or even taping the QC guys to the toilet.

[Tim Johnson]

Make sure your coolant is PH neutral. Check it with litmus paper. When the coolant is alkaline, it will sort of annodize itself.

 

You can also have the plating people caustic etch (if you don't need o-ring type finishes) or ultrusonic etch the parts before plating. This will remove the water marks and tiny scratches.

[Mr. B]

have you ever tried cutting aluminum with alcohol in a mister type unit? I used to cut vaccum form plates that had to be annodized and that worked great but you do need ventilation, as for scratches but some of the white cotton gloves for the QC and shipping people but it will do nothing for the putz's