Had another job come up for an aluminum part! Was a good opportunity to really dial in speeds and feeds for the first prototype.
Stock was .5" thick 6061
Single Flute .25" endmill
Adaptive clearing toolpath from Fusion:
.25 DOC .03" stepover, trochoidal milling
70 IPM 15k RPM
Results were very good! No pictures unfortunately as the part is not in production yet.
oops! photos that I uploaded didn't enlarge properly. reposted again. sorry.
Congrats on the nice panel!! Though I'd share a way that I used to make the lettering stand out
A few years ago, I made similar lettering on an aluminum panel for my DIY router.
I painted the panel with flat black paint
I then sanded the panel with my random orbit sander to give it a fingerprint resistant "pseudo-brushed aluminum" look
It came out pretty well
Hi all, first post after perusing the forum for a few days.
I'm trying to determine some "optimal" feeds and speeds for cutting 6061-T6 aluminum on a desktop CNC-type machine (ShopBot Desktop) and there seems to be some contradictory information on the internets.
The few people in this thread that mentioned specifications (RPM, IPM, etc) including the OP and others used a relatively high rotation speed (~12 - 16k RPM). However other reference pages with tables, formulas, etc recommend much slower speeds (~4000 - 8000 RPM). A few such pages are listed below:
https://daycounter.com/Calculators/G...lculator.phtml
https://www.cnczone.com/vb/cnc-machi...uminum-206831/
https://littlemachineshop.com/refere...tingspeeds.php
What gives? Why is there such a wide discrepancy between the recommended speeds and personal experience? Am I misinterpreting the tables / formulas?
Any feedback is appreciated. Thanks
Feeds and speeds depend HIGHLY on the tool itself. What material the tool is made of, and coatings it may have, cutting edge geometry, and the number of flutes all play a major role.
Thanks for the response. Love your name BTW. Always Sunny fan?
Well yes, of course, I understand that. But that's not answering the question. Can you please tell me, specifically, why there's a difference between what these calculators recommend and what people are using in real life?
I would like to know to educate myself so that I can choose the appropriate feeds and speeds when I make my part.
For instance, for aluminum, using the formula:
RPM = (12 * Surface_Speed) / (PI * Cutter_Diameter)
with a 1/4" mill yields: 12*280/(pi*.25) = 4278 RPM.
Now I realize that's just a guideline but why are people cutting at say 12,000 RPM instead of something closer to that number?
Perhaps that formula assumes your bit has two teeth (it doesn't say that, but anyway). Well if you were using a singe flute mill, for instance, then you would want ~8400 RPM instead to maintain a similar chip clearance. We're still not anywhere near the 12 - 16K RPM that seems to be successful for other people.
Anyway, can someone please just step me through the process of how you might choose an appropriate RPM for milling 6061 aluminum with a 1/4" bit?
Thanks again.
SFM is more of a range than a hard target, the 280 you have there from the daycounter site would be at the lower end of the range for uncoated HSS tooling. With the upper range being around 500sfm. Carbide could be anywhere from 800-1500 depending on coating. Aluminum tends to like sfm near the higher end, tends to stick to the cutter less.
What cutters are you using exactly, would be able to help more.
Sorry for the delay, haven't been over there for a few days.
Looks like what I got for milling aluminum was as set of HSS 2 flute end mills from MSC:
https://www.mscdirect.com/product/details/63324719
I have other bits as well such as these and these but I believe the set above was ordered specifically for aluminum
Last edited by pmillho; 05-03-2019 at 04:05 PM.