Speeds & Feeds Software

MontanaAardvark

MontanaAardvark

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For the last year, I've been using the CNCCookbook G-Wizard speeds and feeds software. One of the reasons I decided to buy the year's subscription is that after it expires, the SW is still usable. (It expired a couple of weeks ago and still does what it used to). It just caps the HP you can analyze at 1HP. I have a Grizzly that's rated at 1HP - the G0704. I don't have a way to measure its HP directly.

During the year I've had the SW, I've noticed it tells me that I can make some cuts that stall my mill when I try them. Just yesterday, I was cutting some 6010 aluminum with a 3/4" end mill, and the SW said I could cut a 3/4" wide slot, 3/16" deep at 15 IPM and it didn't say it was an aggressive cuts. The SW said it would take 1/2 HP, so I figured I should be able to do it. The tool didn't get it's full diameter into the cut before the cut stalled the motor. I didn't look for the biggest cut I could make without stalling it, but I made the cut in .050 passes, and the program says those cuts are about 1/8HP.

I'm running my motor wide open here, almost 2200 RPM, and it tells me to do that the majority of the time I set up cuts in Al. The manual says it's a 750W brushless motor but gives no details on its horsepower curve.

Is this a software problem in the G-Wizard calculator or am I just doing dumb things? I thought with the motor torque derated 50% it would work. I ended up doing the cut at 12.5% of the motor badge.

If this is a SW problem with the CNCCookbook software, what would you recommend?
 
750 watts is one HP (actually 746 and change). But that is your INPUT power. Output power will be considerably less. Welcome to Chinese power ratings, sometimes they are even further from the truth than yours...
 
I also use G-Wizard and have found that I need to slow the feed rate or DOC from what it indicates but I am used to doing that and figure it is just me not understanding some aspect. We to be honest, probably not understanding many aspects.
 
Boswell said:
I also use G-Wizard and have found that I need to slow the feed rate or DOC from what it indicates but I am used to doing that and figure it is just me not understanding some aspect. We to be honest, probably not understanding many aspects.
Click to expand...

I didn't say this part because I didn't know if anyone would get it, but you will. This cut was already done by adjusting the "tortoise/hare" slider from 100% aggressive to about 30%. It originally had it as a 1 HP cut, feeding at 36 IPM. I dragged the slide toward the conservative side until it came to about 15 IPM, which sounded reasonable.

Is that the kind of slowing the cut speed/DOC reduction you do?
 
I have never tried a 3/4" full slot, but for a 1/4" full slot in 6061 and a DOC of .125 and 2500 rpm. I can go about 8 or 9 IPM. My problem though is not overloading the motor but I will gum up the mill bit. (3 flute) I am using a Fog-Buster coolant system and I am sure I could get more speed if I was using flood coolant.

To address your question more directly, I almost always am at the turtle setting or 1 to 2 notches to the right. The times that I have had issues have been with cooling and chip removal, not HP. I hardly ever use my 3/4 end mill and when I do it is usually as a fly cutter substitute. When my End mill would clog up, it would bog the motor down because the bit would quit cutting due to the Aluminum welded to the cutting edges. could that be the issue more than just HP ?
 
I use GWizard feeds and speeds calculator. I have much better luck with the slider in the 20-30% area.
Sometimes the program come up with some numbers that are very hard to swallow.

If there is an error data input, often the box that had the error will auto correct to 0.

But even going back and making sure the tool diameter, or depth and width of cut is not zero, some of the advice on feeds is very generous.
 
Boswell said:
I have never tried a 3/4" full slot, but for a 1/4" full slot in 6061 and a DOC of .125 and 2500 rpm. I can go about 8 or 9 IPM. My problem though is not overloading the motor but I will gum up the mill bit. (3 flute) I am using a Fog-Buster coolant system and I am sure I could get more speed if I was using flood coolant.

To address your question more directly, I almost always am at the turtle setting or 1 to 2 notches to the right. The times that I have had issues have been with cooling and chip removal, not HP. I hardly ever use my 3/4 end mill and when I do it is usually as a fly cutter substitute. When my End mill would clog up, it would bog the motor down because the bit would quit cutting due to the Aluminum welded to the cutting edges. could that be the issue more than just HP ?
Click to expand...

Thanks, Boswell, and MarkDavis,

I'm also using Fog-Buster, so that's possibly a factor. I've been trying to come up with a way of going to a flood coolant, but haven't yet.

I have a surfacing cutter, 1-1/2 cutting diameter but only three carbide inserts - so you don't want to move it too fast. G-Wizard told me I could take 1/8" cut, but I ended up barely able to take half that, and .050 worked best, then, too.

It seems it's just best to put the slider where you're talking about - no more than 35% It makes me wonder what sort of machines are behind the assumptions he wrote into his software. Do the results work well for anyone?
 
You might try emailing Bob, He was very responsive via email when I had a question some time back.
 
I have a friend who is a long time pro CNC machinist, both lathe and mill. His 15 HP mill he frequently has to run at 20-30% of what Bobs programs says he can do. He finally gave up on G Wizard. He has a monster flood coolant set up and even with garden hose type delivery he can not cut as fast as GW says. I think you can read endless threads on PM about the inadequacies of the program. My self, I find it worse than worthless, i would rather go by feel and chip color and surface finish than trust the screwy recommendations that GW gives me. I have given up caring about what the believers say about it, it does not work for me and countless others. Twice I have written to Bob, and respectfully questioned why my results are so wacky, no response............
 
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