Build Thread- G9732 Conversion

[Ed from NY]

Hi everyone,

I'm looking to covert this 14x40 5HP lathe.

This is going to be a very challenging process for me. I never messed with servos before and I'm not quite sure how it will all fit together... I'm hoping to take advantage of some of the experience you guys have and perhaps make fewer mistakes.

I'm keeping everything 3-phase. Power is supplied by a PerfectPhase unit. So although power is stable I still have a high leg -- no isolating transformer. I'm hoping this will not be an issue.

The machine will primarily be turning drill rod, but I want to keep the options open so I do not want to give up chuck flexibility or travel -- though I'll have to figure out how to make a 5C system work in there, well a topic for another day

The initial conversion will not touch the spindle motor. I may add an encoder just to synch and do threading, but even that is not a high-priority. No ATC or stock feed either

What I want to achieve is repeatability and the use of higher SFPM.

For a controller I'm thinking just Mach3 (or perhaps EMC if I decide to go with a higher resolution encoder for the spindle). I could be mistaken, but I do not think it would make sense to invest in Flashcut or a non-PC controller in this case. Please let me know if that sounds all right

Well, that is kind of the background

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So, for the specifics...

I'm considering the AC brushless servos from Automation Direct. They call that line SureServo. As I mentioned I do not have much experience on this and to get a matched motor, driver, connectors and (hopefully) some level of vendor support would be a big help.

The fist decision then is/was "low inertia" or "medium inertia"... Quite frankly I do not know if that would make any difference for a lathe, but I picked the low inertia.

The second decision is/was the size of the motor (I'll be using ground ballscrews). I'm thinking the 1000W for Z and 400W for X. My reason to get the smaller motor for X is to have less bulk in the carriage. Does that make sense? OTOH, I do not mind having the reserve power in Z.

The specs:

SureServo 1000W
Constant Torque (N.m): 3.3
Peak Torque (N.m): 9.9
Rated Speed: 3000
Max RPM: 4500
Continous Current (A): 6.8
Peak Current (A): 18.7
Terminal Voltage: 230 VAC

SureServo 400W
Constant Torque (N.m): 1.27
Peak Torque (N.m): 3.82
Rated Speed: 3000
Max RPM: 5000
Continous Current (A): 3.3
Peak Current (A): 9.3
Terminal Voltage: 230 VAC

One question that has me going in circles is brake or no brake? What is the brake used for? If it is used for E-stops then it would be a good thing. If it is only used on power downs to avoid axis creep then it would be meaningless. I presume that to hold position while turning or facing the break is not used... is this right?

Anyway, still in the very early stages.

Thanks for any/all input

[Ed from NY]

Well, I'll try to give Automation Direct a call next week -- no hurry a lot going on over here so this conversion is taking a leisurely pace.

I got the Z ballscrew (see pic). It is a THK C5, 5mm lead, 32mm (1-1/4") diameter, 1239mm (48-3/4") length, and 940mm (37") travel. I figure C5 is okay, it is beefy enough not to wobble too much (especially when hooked up to a heavy carriage), and the travel and length are about right. I looked at the specs on the THK site and they seemed okay.