I have a late 70's shizouka cnc mill with the bandit controller. The controller has burned-up two cards and I want to retro-fit it. I would like to save the power supply and the servos. I just want an updated servo driver and add mach 3 software to a pc. I have no interest in playing with g-code on an old style controller.
Does anyone know if I can simply get another servo driver and put it on top of the old bandit. I'd only use the bandit to power up the servos.

Thanks,Brian

Wonderful mill, wish I owned one. Do you have the tool changer with it?

I'm pretty sure you have resolvers on the servos. If so, they need to be changed out to encoders. There's a step to servo driver from gecko or rutex that will then work with Mach. You'll have to check that the voltage range on this servo driver is compatable with the power supply voltage you have.

Karl

Thanks Karl for the tip.
Yes, it does have the tool changer. If I loose the functionality of the tool changer in the change to gecko/mach, that's okay. the spindle servo has a different bolt pattern than the x and y, is it different? The old servo driver cards are the same for x,y, and z.
I have no schematic for this mill, but the label on the spindel servo is as follows;

26 lb./in 8.6 A

Max 3700 rpm 140V 47A

Tacho 7 f90-845 IP 44 IC 40

What are the pin-outs on the servo, there are 9?
What is the difference between a resolver and an encoder? Thanks, Brian.

First, I'm looking to purchase a tool changer for a taper 40 knee mill.

I can't answer all your queries. A resolver puts out a sine wave, encoders put out digital pulses, genarally an A,B, and Z channel. A and B are offest by 1/2 pulse so you can tell direction of roation. Z is the index or 1 pulse per turn. Resolvers are obsolete.

if you take a servo apart you should find that most of the wires are for the resolver. There should be two or four wires, probably larger that go to power the servo itself. These run to the driver + and - contacts. You'll have to mount a new encoder.

You'll spend huge bucks updating a spindle servo. And I think Mach software may not drive one. Look into a three phase motor and VFD drive for your spindle. I did this on a Hardinge CHNC with great success.

thanks Karl,

The tool changer control box also controls spindel rpm. So, I need to retain it for the time being because i may be looseing this function with the pc idea.
Are you saying that the spindel servo is different from the x and y?
No one makes pc controller software that understands resolvers, is that it!
It sounds like this retro-fit would require new servos, power supply and drivers i.e;logitrol systems. Thanks, Brian

The spindle servo is MUCH larger than your x,y, and z axis servos. Maybe we misunderstand each other here, to me a spindle servo turns the spindle. Are you thinking of the Z axis servo?

Resolvers are totally obsolete, don't know of anything that fools with them anymore. Not that big a job to replace it with an encoder.

You should be able to keep the servo motors themselves and the power supplies for your new control.

if you ever decide to toss that tool changer, let me know. Or, why don't you just toss the whole machine and give it to me? <GRIN>

Karl

I guess there was some confustin. I was calling the z axis the spindle servo. I'll stop doing that. The z axis SHOULD be slightly more powerful because is feels the full force of gravity in the vertical component, whereas x and y only see the mass of the table and friction.
So, your saying, I can keep my servos and slip an encoder over the shafts!
That would be great and save me big bucks! All I would need is a gecko driver and mach software ( cheap). I'll let you know if I need the ATC, if only for spindle control.
Brian
There's one on e-bay for 5k right now.

If you have a rear shaft on the motor, it pays to look at through-hole encoders like Renco, rather than fit a separate encoder and coupling, usually you will find the resolvers are fitted to one side and geared up about 10:1 due to them being much lower resolution than an encoder.
Al.

I see that ebay Shizouka doesn't have the tool changer. I have a very similar mill I'd like to mount a tool changer on. I'd be glad to help solve any issues caused by its removal and help pay for your gecko driver.

I like usdigital.com for encoder kits, very inexpensive. They have all kinds of sizes and models to fit nearly any application. On my CHNC, there was no back motor shaft or mounting room in front. So I mounted the encoder to the end of the ball screw. Works great, but if a belt ever breaks it might get exciting.

God luck with your project.

Karl