Does anyone have any experience with cutting tool steel on an 1100? When you calculate your speeds and feeds, how much of the available 1.5hp do you aim to use?
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Does anyone have any experience with cutting tool steel on an 1100? When you calculate your speeds and feeds, how much of the available 1.5hp do you aim to use?
For any 3-phase motor with VFD "available" HP varies with speed. Below the motors rated base speed (the RPM @ 60Hz frequency), the motor is essentially constant torque, which means HP reduces linearly with decreasing RPM - at 30Hz, you'll have full torque, but only about half the HP. Above base speed, it's constant power, which means torque reduces linearly with increasing RPM - at 120 Hz, you'll have only 1/2 the torque you have at 60 Hz, but the HP will be the same. This all needs to be taken into account when picking RPM and feedrate. You're sometimes better off deviating from "ideal" RPM and feedrate to accommodate the motors characteristics.
Regards,
Ray L.
Do you know if there is a graph or other information regarding the "available" hp at certain speeds? Or an equation I can use to figure it out?
Some good information posted by 'Keen' in these threads. Haven't seen him on here in while though.
http://www.cnczone.com/forums/tormac...teel_k600.html
http://www.cnczone.com/forums/tormac...ned_steel.html
http://www.cnczone.com/forums/tormac...ugh_steel.html
I'm cutting a bit of P20 tomorrow, so I might chip in with what I find as well.
Thanks Peter, that is some good information. Please let me know how you make out with the P20 and, if you are willing, the speeds and feeds you used.
Like I said, both relationships are linear. I don't know the specs for the Tormach motor, but let's assume 1.5HP, with a base speed of 3600 RPM @ 60Hz.Quote:
Originally Posted by adamboon
Below 60 Hz/3600 RPM:
HP = 1.5 * RPM / 60HzRPM
Torque = HP * 5252 / 3600
Above 60 Hz/3600 RPM:
HP = 1.5
Torque = 1.5 * 5252 / RPM
At 3600 RPM, you'd have:
Power: 1.5 HP
Torque: 2.18 ft-lbs
At 2000 RPM, you'd have:
Power: 1.5 * 2000 / 3600 = 0.83HP
Torque: 2.18 ft-lbs
At 5000 RPM, you'd have:
Power: 1.5 * 3600 / 5000 = 1.08 HP
Torque: 1.08 * 5252 / 5000 = 1.13 ft-lbs
Regards,
Ray L.
Thanks for that Ray. Now I just need to find out the specs for the Tormach motor. I couldn't find it in the manual I downloaded, maybe somebody out there knows what it is. Now I can better calculate if my pretend speeds and feeds are within the capabilities of the Tormach.
Hi Adam
From the tech sheet on the Tormach web site
100-5,100 RPM
110ipm in x and y
90ipm in z
Max power 1.5hp
Peter
You're trying to eat the elephant from the wrong end.
Horse power calculations are very approximate. Horse power at the cutting tool is not the same horse power as at the motor. Whether you can use the available horse power depends on other factors not included in the calculator. Horse power calcs are only good for telling you if you are way outside or inside your limit. Constant torque to rated rpm and constant hp above rate rpm is more than close enough for your calcs considering all the other uncertainties. Hence the reason you can't find what you are looking for is because it is of low interest.
Don't forget to allow for the speed difference between the motor and the milling spindle.
Phil:)
Quote:
Originally Posted by adamboon
Constant horsepower calculations don't mean squat if you're cutting D2. If your spindle speed is too fast, you'll fry your cutter in about 6 turns.
A2 is a little more forgiving, and with the right tools, 4140 in an annealed condition and with the right tools can be at some fairly high feeds and speeds.
Went quite well, posted the pics/info in a different thread to avoid hijacking this one.
Quote:
Originally Posted by adamboon
Just for completeness on the motor topic:Quote:
Originally Posted by HimyKabibble
The motor is 1.1 KW, 230 V, 60 Hz, 1715 RPM, Delta config.
I had a spectrum analyzer hooked up to mine to check unbalance, and the motor to pulley ratio was 1.26 (from the response peaks), on the high speed ratio.
Tormach designed it to overdrive to ~140 Hz with the VFD. 1715 RPM * (140/60) * 1.26 = 5042 RPM.
Regards,
Geo
A2:
A-2 steel is an air hardening alloy chromium-molydenum-Vanadium die steel. As a cold work steel grade containing 5% chromium.
http://www.otaisteel.com/products/co...ld-work-steel/
D2:
1.2379 die steel is a kind of high carbon high chromium alloy tool steel. It has high hardness and wear resistance after heat treatment, and has strong hardenability and good dimensional stability. 1.2379 die steel and NAK80 die steel are suitable for making. High precision long life cold working die and thermosetting plastic mold.
http://www.otaisteel.com/din-1-2379-...21bohler-k110/
4140:
AISI/SAE 4140 grade is a versatile alloy with good atmospheric corrosion resistance and reasonable strength. It shows good overall combinations of strength, toughness, wear resistance and fatigue strength.
http://www.otaisteel.com/products/qu...0-alloy-steel/
H13 mold steel have good tempering resistance,high temperature wear resistance,good quenching and heat resistance impact resistance,high touhness,good Thermal cracking resistance.It can be nitrided to increase wear resistance. You can content Songshun steel to get h13 mold steel.
Contact: https://steelpurchase.com/about-culture/