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Need to polish and deburr 6061 aluminum

Q. I have a burr and finishing problem on aluminum. We are making a product with dozens of cross drilled holes about .072" diameter which intersect a larger hole that is reamed second. The ream is pushing a moderate sized burr into the small port holes. We are using 6061 aluminum for its cost and ability to be anodized with a rich color. However, we need to polish the outside of the work piece as well as eliminate the burrs. We've been told by the local electropolisher that they cannot do 6061. Any suggestions on how to finish this work piece so the final product is polished, burr free, and cosmetically pleasing?

Thanks,

Michael Quinn
- Newark, New Jersey
2002

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Deburring aluminum, but only mechanically

Q. We need to deburr fine burrs of aluminium after milling the part. The burrs are very thin and the only way to detect them is by 6X magnification.

Parts to be deburred are small (about 100 mm X 60 mm X 40 mm) and they have a very small pockets (10 X 10 X 10 mm). Parts are HFF used on satellites (microwave filters)

We are looking for a mechanical process -- chemical or thermal processes are not allowed. Nowadays we are removing them manually by spending tons of hours at a microscope. The idea is to find an automatic way.

The main important problem is that we need to deburr the part without any geometry changes. The edges must remain sharp (90°), and no fillet radius is allowed.

If anybody knows any process and can help us I will be really grateful.

Ruben Gonzalez Vinuesa
- Barakaldo Spain
June 27, 2013

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July 22, 2013

Q. Good Morning,

Answering to Mr. Kneedler.

The number of pockets are from 20 to 40, it depends on the part. The geometry is quite simple, square or rectangular. The tolerances are tight: 10 microns.

To manufacture them we are using a small mills and we machine several times the same finishing path with the tool, in order to eliminate the burr as much as possible. We use PCD milling tools. Machining time is about 10 minutes per pocket.

For manual finish, we use sticks, to keep the edges sharp. The time for each pocket could be 2 or 3 minutes of a person looking through a microscope.

Asking to Mr. Kenton

Please would you be kind enough to explain deeper the sentence: "mechanical deburring system using dry organic media with a small amount of pumice"

Which kind of dry organic media? any commercial trade mark? any suggested machine? We have a OTEC vibration machine, wet system. It helps but we still haven't found the desired solution. Same questions for the pumice, if you can detail some more information about the pumice to be used I would be really grateful.

Kind regards, and thank you very much for helping me.

Ruben Gonzalez Vinuesa
- Barakaldo, Spain

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Ed. note: Hi Ruben. We avoid recommendations of specific brands or sources in this forum because it has repeatedly led to hard feelings. People can suggest generics in the forum, and you can post a request on our RFQ page that suppliers privately contact you with their sales literature. Good luck.

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July 22, 2013 A. In regards to dry organic abrasive mix, consider a wood sawdust with a binder to hold the pumice in the mix. It works extremely well on small parts. Good on jewelry detail and produces a satin or antique appearance on all part without effecting dimensions in a 24-hr. period. You mentioned an Otec machine. If you have the centrifugal system, there is a nylon abrasive shaped media that is also run dry that comes from Japan only. It is not that new on the market but few people seem to use it. It looks like normal plastic media but behaves like dry organic media. It is expensive @ around $12-16/lb. but lasts a long time. It comes in 3 shapes down to 2 mm in size. AF Kenton retired business owner - Hatboro, Pennsylvania July 22, 2013 A. Sr. Vinuesa, Thank you for the information. The first thing to do is understand your burr. There are three types of burrs: Poisson, Rollover and Breakout. What type of burrs are you encountering? Are you using a horizontal mill or vertical mill? If you are using a vertical mill I would recommend changing to horizontal if possible. I would also look at tool path and tool selection with an eye toward eliminating swarf. Another thing to examine is swarf removal during the machining process. In other words, if you are using a vertical mill and a bad tool path with poor swarf removal techniques, you could be causing the problem yourself so why not think of better ways to get the swarf immediately out of the hole before mashing it in with the tool? Ideally, you will have long spring-like 'shavings' and not a hop-and-skip tool path. Assuming all of the parameters are set in place and you have improved all of your inputs I would then draw a Process Map along with an Ishigawa diagram. It will be interesting to know the results. Assuming that you take all of these steps and make all the improvements and investigations it could be that you will settle on two options. One, deburr using current method but while the machine is running and work on improving labor times. Two, try a light pressure blasting method (I would try glass first). We can't offer names of companies and suppliers because it is against the rules of this website. Blake Kneedler Feather Hollow Eng. - Stockton, California