[Bob La Londe]

Is there a good set of graphs available for speed range 1 and speed range 2 for the PCNC1100 torque and horsepower curves based on RPM?

My speed and feed calculator does have a machine profile for the 1100 (and the 770) in the high speed range, but I would kind of like to find a secondary source and verify it with a few more data points entered in the parameters. It does not include a machine profile for low gear.



I had to make test cuts and create my own machine profiles for my other machines. They are far from perfect, but they get me by.

[MetalShavings]

If the feeds and speeds calculator you are alluding to is the one put out by Eldar over at HSM Advisor then I really don't have any info I can offer. If it's not then, perhaps HSM Advisor can give you an additional source of data to work with.

I have a 770 mill and according to the power curve that's generated for my mill, I get the most torque at about 4000 rpm. There appears to be an overlap of this same rpm/torque range regardless if I'm running the smaller pulley or the larger pulley. Since I like to go fast as opposed to going slow and strong, I try to set my feeds and speed around the speed side of the equation; although, I have generated feeds and speeds with my various cutting tools centered around maximum torque as apposed to maximum speed. I used the maximum torque settings when I was cutting 303 stainless.

The irony here is that with maximum torque I can take deeper cuts but at a slower feed rate. When running with maximum feed rates I'm taking shallower cuts so the time it takes to complete the same tool paths using one or the other of these two feeds and speeds calculations generally isn't to much different in terms of the time it takes to complete a tool path to a finished part or parts but, I use cheaper cutting tools. If a guy is using higher end cutting tools perhaps the benefits of custom profiles with optimum speeds and feeds would then be of greater benefit.

MetalShavings

[jwatte]

I asked Tormach customer support, and they gave me an approximate shape of the power curve.
This is for the BLDC spindle in the 440, so it won't help you, but it has max power between about 3500 and 8000 rpm, and looks like any other BLDC motor outside that (power linear to zero at 0 rpm, and slight dip after 8000.)

On most of these small mills, the amount of material you can remove seems to be limited by the horsepower of the mill, so shallow-and-fast or deep-and-slow seems to be approximately the same. I guess that relation will continue to hold until you get to the point where you are RPM limited, or tool strength limited.
And at that point, maybe the calculator should let you dial in feed and speed, and it will tell you optimal depth/width of cut instead :-)

[David C. Allen]

Hello Bob
I would look at the vfd frequency vs commanded RPM

http://www.lhp.co.in/images/img_vfd_9.jpg


FS Wizard Machining Calculator - Page 15

1100 Series 3 High Belt Speed
RPM Power Torque
250 0.14 2.94
1000 0.66 3.47
2000 1.50 3.94
4300 1.50 1.83
5120 1.00 1.03


David

[Advil]

HSMAdvisor has an option to download more machine profiles from their online server. It has the 770 and 1100 low belt profile for hp and torque. I use it constantly.

[MichaelHenry]

HSMAdvisor has an option to download more machine profiles from their online server. It has the 770 and 1100 low belt profile for hp and torque. I use it constantly.

I just checked HSMAdvisor Cloud and could only find the 5120 rpm PCNC 1100 profile. Is there a secret to finding the low speed version?

[Advil]

Well I apologize I could have sworn there was a low belt curve in there for the 1100 but I don't see it. Did a bunch of internet searching and came up empty.

[Zetopan]

Is there a good set of graphs available for speed range 1 and speed range 2 for the PCNC1100 torque and horsepower curves based on RPM?

Generating such plots for induction run motors is actually easy to accomplish. Simply tell me the following details for your Tormach and I can generate the continuous performance plots. You can read the VFD frequency directly off of the VFD display.
1. Minimum spindle RPM and VFD frequency on the low speed range.
2. Maximum spindle RPM and VFD frequency on the low speed range.
3. Minimum spindle RPM and VFD frequency on the high speed range.
4. Maximum spindle RPM and VFD frequency on the high speed range.

Knowing the spindle RPM when the VFD is at 60Hz establishes the maximum HP and torque point and everything else is determinable from those details. Attached is an example spreadsheet plot using the nominal Tormach supplied data for the PCNC 1100. This assumes 100% efficiency for the VFD, motor, belt drive and bearings. If you want greater accuracy you would need to measure your specific Tormach mill.

Also note that Tormach specifies this mill VFD and motor being rated at 1.1KW (1.47HP) continuous and 2.8KW (3.75HP) peak, while I have only plotted the continuous ratings.

[Bob La Londe]

First off. Yes I am using HSM Adviser.

I was not aware of the ability to download additional machine profiles. Not sure why. I thought I had pretty well explored the program. As somebody else noted they do not have a low speed profile,

What I did find that struck me as interesting is that they show profiles for generic 24K water cooled spindles from 0.8kw to 2.2Kw. I happen to have three small mills using these type of high speed spindles. One with a 0.8Kw main spindle and two with 1.5Kw spindles. I'm not sure I agree with profiles data points, but I'm going to give them a try. On the 1.5Kw they show useable power as low as 4000 RPM. I have never tried to cut below 8000 RPM with that spindle before and 6000-8000 is the typical lowest speed you see listed for this type of spindle. I'm certainly going to find out. Previously I had been using the generic linear power curve you sometimes see for this type of high speed spindle motor. Please note for most of the type of work I do even as little as 0.01 HP is useable power.

For a really interesting bit of information: I saw a profile for the Bosch Colt 1HP trim router. I was quite surprised to see that. I actually have one on my little gantry router. I don't use it often, but I do use that machine once in a while for "special" projects. Among other things I also used a Bosch Colt on my Taig. Well a different one. I wore out several of them over a couple years.