Large lathe retrofit

[Fabric8r]

Hello:
I have read alot of threads here at cnc zone. But I have a question i'm not sure about. I have a large Cincinnati slant bed CNC lathe. I will try and post a picture at the bottom. What I was wondering about is. The Controller for this machine is dated. I was wondering if I can run it off of a PC with software like mach1. It has servos and working drives. Would this work. I am also wondering if the spindle would beable to have variable speed controll with this software. One last question is there a way to have a hand jog wheel for the movement of the X and Z axis.
Thank you, Scott

[Al_The_Man]

Something like Camsoft would fit the bill, as far as the variable speed spindle, it depends on what type you have right now, i.e. DC or AC variable speed or just a standard 3ph motor. This would also have handwheel operation as well. You can also use your existing drives and motors, it would help though if the motors have encoders and not resolvers.
Al

[kong]

Mach2/3 outputs step/direction signals from the PC, so your drives would need to support this. Apart from that, I see no problem using the software. You can add MPG's as handwheels.
As for spindle speed, I don not know much about it, but I believe Mach will output a PWM signal to control the spindle.

[RotarySMP]

You say the controller is dated. Does it still work? If not what is wrong with it? What are you hoping for from a PC retrofit that it can't do today?

[Fabric8r]

I just baught the lathe. I have not recieved it yet. I was told it has ben in storage for a year and it was working prior to that. I was told the controll screen was cracked. I was also researcing on the web and I saw a centroid retrofit on this same machine and they said that the machine with the original controll was costing them money. I am also used to using a hand wheel to set up the machine and to cut jaws. I don't see one on this machine. I also would like to program the machine with ONECNC. and I dont now if this machine can read anthing more than just the tape reader.
I looked at Camsoft but it looks like it is to spendy for me. I have heard good things about Mach1 and would like to look into that. What do's MPG and PWM signal mean. I was also wondering how can you tell if a drive excepts step and direction signals.
Thank you for the replys, Scott

[RotarySMP]

Working from the Axis:
You say it has servos. Are the existing drives set up to receive Step and Direction from the controller?
If so you have a wide choice of software (I use TurboCNC as it has lathe threading, and I think the only other one is Mach2). You will just have to strip out the controller and wire up the drivers to the parallel port.

If the existing drivers don't have step and direction interface:
Is the feedback from Encoders (good) or Tacho's (bad, but I think Rutex has a TAcho to encoder widget).

Are the servos DC? What voltage. If the motors are lower than 80V and it has encoders, you could toss the current drives and use Gecko's. For higher voltages Rutex. If they are AC servos....good luck on ebay.

For the spindle, is it DC or AC? Can you interface with the spindle driver? Most PWM DC drivers and 3 phase VFD's can be controlled by a 0-10VDC anlog signal. If you can find that interface, you could buy Peter Homanns Digispeed to interface between the digital step/dir output of TurboCNC and the 0-10V analog input to the spindle driver.

The spindle feeback for TurboCNC is a simple 1/rev you can do with a Sharp GP1A05. I'm not sure about the spindle control interface of Mach 2, but Art has an excellent manual on his web site.

TurboCNC can be modified to look at a jogging wheel. I am sure Mach 2 can as well. In Turbo CNC you'd have to write a little code and recompile (although I am sure someone already has this). For Mach 2 again check Arts manual.

The scope of your work could be between supply a PC and wire it up to, if the machine has AC servos, whoses drivers are not step and direction interfaced, with a spindle controller which can't be controllered through a simple interface, stripping out all the motors, drivers and control and replacing it all.

[HuFlungDung]

I'd be cautious about using Mach2 unless it has the means to write logic files. Controlling the tool turret is complex enough when you can write various experiments in logic to try to emulate however the machine originally behaved. Sometimes though, this is handled by a seperate, dedicated servo card, with its own burned in routine for controlling the turret indexing and clamping. If you went this route, you'd need to know if Mach2 can somehow communicate with this auxilary turret servo controller card.

Al can probably give you some pointers on this, its a bit beyond what I know about.

Another question to ask, can Mach2 perform constant surface speed? Does it do tool radius comp correctly? Does it allow multiple coordinate systems? Does it use standard cycles for drilling, tapping, threading, turning and finishing?

How much "safety logic" does Mach2 incorporate to trap operator blunders and such? I don't know the answers, but safety is of paramount importance when running these machines.

Practically anybody could make the spindle go round and cause a couple of axis to move, with the absolute cheapest software. Even Camsoft's default controller files had practically no traps built in to catch operator blunders, but the saving feature was I could at least write up my own.