Re: [CAD_CAM_EDM_DRO] Any "Best Practice" Recommendations for clearing chips and feed/speed when

You need a regular dust collection system, not a shop vac. One of the best, and
easiest to build is the vortex system, (see rec.crafts.woodworking archives).
It's the same thing with grain silos; Enough fine particulate matter plus
commutator/switch sparks equals instant explosion. There are several ways to
move the air into/from a dust collector, but you want a zero sparks solution.
One such solution would be to use an air amplifier. These work on the Coanda
Effect, which has to do with how gasses and liquids move across a curved
surface. Coanda was one of those multi-discipline geniuses who lived back
around the early part of the last century. His main gig was organic chemistry,
but he also designed, built, and flew, the first jet airplane. An air
amplifier is a three opening unit that acceptss air from a compressor, and uses
it to induce an airflow into one side, and out the other. The specs I've seen
indicate that it works on a 1:25 ratio; I.e., a 10 mph flow from the
compressor equals a 250 mph flow through the device. This spec is the same
from several manufacturers, so I presume this is the max for practical air
moving devices, though no doubt the figures and sizes are different for denser
stuff like liquids.

While I'm on the subject, try to segregate as much as possible the results of
your aluminum work from your ferrous metal work. Rust, (ferrous oxide), mixed
with aluminum oxide equals thermite, which burns, (redox reaction), in the
neighborhood of 5 or 6 thousand degrees, and has been known to self ignite.....

Bill

On Sun Dec 23 00:45:12 2001, glee@..., <glee@...> wrote:

>Well, tonight I switched from cutting wood to machining 6061 aluminum with
>my Sherline Mill using a 1/8" end Mill to Mill a part 1" x 1.6" by .25"
>
>It was an education to say the least. In the process of documenting the
>results, I arrived at some questions:
>
>When I was practicing on plastic and wood, I ran the ShopVac with the
>intake nozzle next to the cutter. This way, it was a superbly clean
>process.
>
>When cutting aluminum, I used WD40 From time to time to lubricate the
>cutter. I noticed that the WD40 label says "Highly Flammable - propane." I
>decided that I would not use the ShopVac and the WD40 at the same time for
>fear of starting a fire inside my ShopVac and making my ShopVac a flame
>throwing jet engine. (Am I correct in this concern)
>
>Since I was no longer using the ShopVac I now had a micro chip problem.
>This was further complicated by the WD40 (used in moderation) and resulted
>in an aluminum "Slurry" surrounding the cutter and resting on top of the
>part.
>
>No problem, I thought. I used an acid brush to brush away the debris -
>still wishing I could run my ShopVac.
>
>Well, combine the above with the lessons I learned about climb vs
>conventional milling as well as and feed/speed rates, I have probably
>broken many rules tonight not to mention possibly destroying my cutter. At
>least I am learning and having fun while making chips.
>
>So, now that I have shared the gory details, I will ask for
>feedback/correction:
>
>1. Any ideas on the removal of chips
>
>2. Any ideas on the lubrication of the cutter (It's an 1/8" end mill)
>
>3. I experimented with feed rates and speeds as I was encouraged to do. I
>came up with 2500 rpm, 5-10" ipm on XY and 1 ipm on Z seemed to work. I
>would welcome some recommended rates for my sample part
>
> Spindle Speed?
> Feed Rate XY?
> Feed Rate Z?
>
>This is a learning adventure for me. I'm open to all kinds of feedback so
>fire away :-)
>
>Thanks. I cant wait to check my email in the AM to see what kind of
>responses I get....
>
>
>Eric Mack
>glee@...
>
>
>P.S. I am documenting my adventure to try and write a tutorial to help some
>future lost soul do this. For now, I return to wood and plastic for
>practice until I master the speed/feed stuff.

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