SuperPID-help cutting aluminum?


(Mike Price) #21

I believe they are. At least i get a different feed recommendation for each one i choose. It also shows the hardness value (Janka) for each one.


(Gerald Mackelburg) #22

See attached for what I get for Balsa (Janka 90) and Pumpkin Ash (Janka 990) with v4.45 of GW (no difference.) What do you get?Balsa and ash.pdf (604.8 KB)


(Mike Price) #23

not a big difference but balsa 9.237, ash 7.544. To be honest i don’t use GW for wood or even for the shapeoko. I do use it at work for the HAAS mill and lathe, and it is a must for me in that front.


(Gerald Mackelburg) #24

Where did 9.237 and 7.544 come from?


(Mike Price) #25

It was on my lathe machine profile because i was using it. On the dewalt profile its 4.412, and 3.603 ipm


(Gerald Mackelburg) #26

I’m confused! Can you please post screenshots of your GW calculations?


(Mike Price) #27

i bet its because of the min and max of the dewalt giving you the same for material.


(Mike Price) #28


(mikep) #29

Are you optimizing for cut depth?


(Gerald Mackelburg) #30

The only way I could reproduce your results was to change GW’s router Minimum RPM from 16500 RPM to 5000 RPM and lock GW’s RPM and Feedrate to your values. Strange since we’re apparently running the same software version!

Nevertheless, if you use the same RPM and Feedrate for both species (“Alloys”) in GW, you’ll get exactly the same results for both alloys. In fact, you’ll find that’s the case for all alloys in any of the “Families”. At least that was the case when I checked a few months ago.


(mikep) #31

That’s not the result I get when I also optimize to generate a depth of cut. Yes, the feed and speed numbers end up the same (basically, you run into the limit of the machine) but the greater depth of cut enables a much greater material removal rate in the softer materials.


(Gerald Mackelburg) #32

Can you please post screenshots so I can better understand what you’re saying?


(Gerald Mackelburg) #33

Please feel free to switch to Aluminum if you wish (since this thread is really about that)


Shapeoko XXL Router Options
(Gerald Mackelburg) #34

As shown in the attachment, both the latest GWizard and Kennametal calculators “say” that less than 1/3 hp and 15 lbf are required when cutting 6061 T6 aluminum like this. GWizard “says” that’s true for 7075 T6 too. Kennametal “says” less than 1/2 hp and 23 lbf are required for 7075 (more reasonable IMO). Does your experience and/or measurements contradict this?Aluminum.pdf (1.7 MB)

The attachment also shows the expected factor of 2.7 reduction in force achievable by increasing the router speed from 10 kRPM to 27 kRPM.


(Richard Cournoyer) #35

Those number’s don’t look right.

Ref: 1/3hp (15lbf) vs 1/4?h (23lbf) Perhaps 1/2 hp?? for 7075


(Gerald Mackelburg) #36

Thanks for catching that! I just corrected it. Do you think those values are reasonable?


(Richard Cournoyer) #37

Yes that look about right.


(Gerald Mackelburg) #38

Onsrud claims that keeping cutter chiploads within their specified ranges is critical for cutter life. As shown in the attachmentGWizard and Onsrud.pdf (1.1 MB)
, their 1/4" endmill with the smallest chipload (0.002") is a single flute solid carbide.EM. Forcing GWizard to provide that chipload at the maximum router speed (to maximize MRR) results in a 11.9 lbf force on the workpiece and router (since the cutter’s shank is the same diameter as the cutter). That force would likely cause about 1/64" of added cutting error on a Stepcraft D840.
IMO GWizard would be a lot more useful if users could enter minimum chipload (cutter dependent), spindle speed, and maximum machine force. To be meaningful, those calculations need to properly account for the characteristics of the material being cut. Users would also need to know how much error they’re willing to accept and what force causes it.


(Gerald Mackelburg) #39

Rick and Will,

One of Kennametal’s 2 flute endmils Kennametal Catalog.pdf (1.8 MB)

should provide material removal rates up to 19 times Calculations.pdf (1.3 MB)
that listed in the Shapeoko speeds and feed table for 6061 T6 aluminum. Why?


(Richard Cournoyer) #40

Now we’re entering into the fields of my Ph’d studies…

The lack of stability, dampening and rigidity in a hobby style machine vs. a commercial machine (e.g. Haas) is the reason.