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

Then too, if you want to keep your fingers out of the works, there's allways an
old fashioned squirt gun.....:-)

Bill

On Sun Dec 23 10:19:46 2001, Marcus & Eva, <implmex@...> wrote:

>Hi All:
> Don't use a brush!!!
>You will drag the brush between the cutter and the workpiece sooner or
>later.
>At best, the brush will get a haircut...no big deal.
>At worst, though, the brush will jam in the gap, flex the machine, and cause
>a big gouge in the job when it rebounds.
>The best for applying cutting fluids is old contact lens solution bottles or
>other small squeeze bottles.
>You can apply a drop at a time if needed, with complete control over where
>the stuff goes.
>For machining aluminum, the best product I've found is Relton's "A-9"
>aluminum cutting fluid.
>Not stinky, lubricates well, and available in small quantities.
>Cheers
>
>Marcus
>----- Original Message -----
>From: "yethdear0" <yethdear0@...>
>To: <CAD_CAM_EDM_DRO@yahoogroups.com>
>Sent: Sunday, December 23, 2001 7:35 AM
>Subject: [CAD_CAM_EDM_DRO] Re: Any "Best Practice" Recommendations for
>clearing chips and feed/speed when cutting Aluminum??
>
>
>Howdy, yethdear here again;
>
>Welcome to the wonderful world of machining metal. EWWWWWW! Don't use
>WD40, yes this flammable and you are risking a lot using it for
>machining. Here are some suggestions for you.
>
>Purchase a small air compressor and tank for about $100. Then plumb
>up an air cooling system using 1/8" copper tubing. Make an air blast
>nozzle that is attached to you machine so that it supplies a constant
>flow of air to your cutter at all times. This will cool your cutter
>and blast away the chips too.
>
>Go to www.use-enco.com, they have a variety of spray mist systems
>that you can buy. These work good but they are messy and pose health
>problems if you use them in a confined area. Enco also has a variety
>of cutting fluids and oils that you can buy in small quantities. Some
>of these can be mixed with water or used full strength. I usually
>pour some in a spray bottle and then apply a squirt now and then as
>you need it when machining. They also have a variety of cutting
>fluids and tapping fluids that come in a squirt bottle.
>
>I sometimes use old motor oil. It works good as far as lubricating
>but can smoke quite a bit. I just apply it with a brush. No matter
>what, you are going to have some mess. This is not a hobby or career
>for a neat freak. I'll usually try to keep the chips out of the path
>of the cutter as much as possible. Then I usually wait till I'm done
>with a project and do a thorough job of cleaning up. One advantage to
>cutting fluids and oils, it keeps the rust away from your machine.
>You'll just have to live with mess. ALSO...ALWAYS WEAR YOUR SAFETY
>GLASSES!!!!
>
>A friend of mine says he uses Windex as a coolant for aluminum. I
>don't know about the ammonia though.
>
>As for speeds and feeds. This is not an exact science. The numbers
>you'll find are "ballpark" at best. RPM is based on the type of
>cutter you are using and the type of material you are cutting. For
>high speed steel cutters on aluminum, a published "cutting speed"
>value is around 400sfm. For steel, it is 100sfm. Now here is a
>formula for determining RPM;
>
>(CS X 3.8) / cutter diameter
>
>Here is how this works using aluminum and your 1/8" endmill
>
>(400sfm X 3.8) / .125 = 12,160RPM
>
>I take it that this is probably too fast for your machine. That's
>okay, it's telling you to run this cutter as fast as you can.
>
>Now for feed, this is based on the recommended chip load per flute
>for your size of cutter. By experience, for an 1/8" endmill, I would
>figure .0003-.0005 per flute. This is the amount of material that
>each flute of your cutter removes for each revolution. Here is how
>this works.
>
>FEED = Chip load per flute X RPM X number of flutes
>
>Using what I'm guessing is your top RPM on your machine
>
>FEED = .0005 X 3500 X 2 flutes = 3.5ipm
>
>Now, where to get all these recommended values. The best place is a
>book called "The Machinery's Handbook" This is also available through
>www.use-enco.com. I know I sound like I work for Enco.I don't it's
>just a great place to get all this stuff. The handbook is the bible
>for machining. It has ALL the information you need if you're serious
>about machining. The book is about $65 but is well worth it. You can
>also find it at your local book stores in the technical section. Just
>look in the index for speeds and feeds.
>
>You can also find published values on the web. Search for "speeds and
>feeds" for aluminum" or whatever material or cutter type you are
>using.
>
>Another good place for info, my web page. I am currently working on a
>database program that calculates speeds and feeds for various cutters
>and materials. Once I finish it, I will make it available from my web
>page at http://www.geocities.com/yethdear0/
>There will also be more useful information posted there as time goes
>by. Excuse the ongoing construction on it.
>
>REMEMBER.speeds and feeds are not exact. Most of the time you will
>have to adjust them as you are machining. RULE OF THUMB..if your
>cutter is screaming and chattering, you are not feeding enough.
>Increase your feed rate or slow down the RPM. Make your cutter CUT
>more. Not too much though, or you will take too big of a bite and
>snap your cutter. You can also break cutters by not keeping enough
>cutting fluid on it and it heats up and the aluminum will weld to
>your cutter. You can also break cutters by not feeding enough. If it
>is screaming and chattering, the cutter will beat itself to death and
>knock the sharp edge off of the flutes. Now you have a dull cutter.
>
>Another RULE OF THUMB. the smaller the cutter the faster your RPM.
>BUT the smaller your chip load will be. (Fast speed..light cut)
>
>It all comes with experience, don't give up and be patient and have
>fun playing with your set up.
>
>Let me know what your results are.
>
>yethdear
>
>
>
>--- In CAD_CAM_EDM_DRO@y..., glee@i... 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@i...
>>
>>
>> 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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