conect cnc lathe retrofit

[daedalus]

Hi,

Finally after 140 odd posts here ive got something to write a project log about.

I bought an old cnc lathe on ebay for next to nothing, its a conect numerical control lathe. Conect sold lathes to schools and colleges in the UK, where as D&M distributed the same products in US.

From what i have been able to figure out the body of the lathe is a Myford ML10, with a 2 hp spindle motor.

The current controller is some kind of proprietary serial interfaced board, which is pretty much obsolete (it used a dos app to communicate, pretty limited, plus i dont have the software).

The spindle motor is controlled by a board by ashe controls,marked fx 1500. This is driven directly by mains, and has its own rectified power supply. The spindle motor has 4 wires running to it from this board, one of which runs through an ammeter on the front of the lathe. Am i right in assuming that this is a bldc motor? (A,B,C+ground) This controller is interfaced to the rest of the electronics by 4 wires (unmarked), which i guess control the spindle RPM.

I have literally only just got this through the door, so still have a lot of wire chasing to do before i know where everything is wired to.

Eventually i plan on installing 2 picstep drives for the steppers, and possibly a mini-itx pc. Still undecided on the EMC / mach3 front, but that can be selected later.

Also i really need to get some tooling, otherwise having this will be quite pointless (starts counting pennys)

[Trapper14]

Awesome, nice to see a lathe around here, way to many mills floating around Keep us updated, looks like its in pretyt good shape.

[mark kemble]

Hi

I have the twin to your lathe and although i have some software but i have never got i to work very well, i am looking to retro fit a new controller.

Compucutter make a four axis controller which could be used for x,y, and the spindle and i have a tool changer on my machine.

I am trying to find out more about the ashe speed control.
It seems a shame to bin all the electrics. I did once get the tread cutting software to work.
I had major trouble with the constant surface speed(css) it always ran at 2500 RPM even if the g codes were altered
Mark

[daedalus]

yep, the ashe control board is a bit of a mystery, i contacted a controls company by the same name, but apparently it isnt one they made.

I am not familiar with compucutters product, but i was planning on building some picstep drives, as most of the designs i can find wont take the voltage being used.

I assume you have a second board next to the stepper drives (mine has a blank space). Is the tool changer stepper driven?

Also i have a really stupid question, but its been bugging me. My tailstock is missing the lever handle on the top, is this for releasing the collet?

I would be posting more frequently, but work have just dropped a rediculous deadline on me, so i havent really had much time to work on it, bar sweeping out the chips.

[daedalus]

Ok, have had a few hours today to mess with the lathe. I have removed the old controller boards, and traced most of the wiringl.

On the question of the spindle controller, i have started to reverse engineer the middle pcb in the hopes of figuring out the pinout. I cant start my spindle as i dont have the software, so this is all deduced without powering up.

My wiring indicates that the contacts 1-6 on the spindle controller act as follows:

1 +?V
2 ground
3 signal (connected to ground via pulldown resistor)
4 sw1
5 sw2
6 Not connected

sw1 and sw2 are connected to a relay on the middle board, which is energised on power up. This is the spindle enable switch.

Pin 3 is driven by a HV phototransistor optocouple, which is rated for 200-300v switching. The optocouple switches between pin 3 and pin 1.

Any appropriate PWM output should be usable to drive this spindle, assuming proper optical isolation is used, as the drive itself appears to be unisolated.

Are you able to control your spindle speeds in software normally? or is it just CSS thats bugged? I dont have the software so dont know exactly how it works.

[mark kemble]

Hi
I am not an electronics enginer but I had thought of controling the spindlemotor with a DC motor control directly conected to a stepper, this being conected via the control on the pc. After all how many times do you need CSS for most turning work. The motor I have is about 200 volts DC the field and armature, there are 4 unmarked wires but I guess it would not be dificult to work out how to wire it up.

Compucutters.com, Make a 4 axis control with to software for retro fitting, it looks a bit heath robinson they are in Coventry an will show you their system if you can go there or see the web.

I do have another pcb in side this may well do the tool turet.

The missing lever just locks the tail stock spindle.

[daedalus]

Hi,

The spindle motor controller that comes with the lathe is pwm controlled, as are the stepper drives in the compucutters box. All you would need to do is route an output pin from the parallel port through an apropriate optocoupler to the drive. I assume mach can produce a pwm signal for spindle speed control. I havent done this yet but hopefully i will get some time off this weekend to play with it, and post some more details.

I am doing pretty much the same thing as the compucutter, but building the stepper drives and breakout myself, as its cheaper, and it should all fit in the fold-out back section. I am keeping the psu thats in there, the spindle drive, and some of the wiring. If you dont mind putting together some pcbs then check out the picstep project on these forums, as its a pretty cheap way to get set up.

I would be interested to know how the tool changer works, could you post a photo of it? I am thinking something like a stepper and solenoid to raise the toolpost off a set of locking pins prior to rotating.

[balsaman]

Is that thing in your living room? If so your wife is very understanding.

E

[daedalus]

Ok, has it been this long since i did anything on the lathe? Really need to pull my finger out! 12 hr work days dont really agree with my hobbies.

I managed to get the motor turning for the first time today. I was right about the spindle drive wiring, so Mark if your reading this then just short the yellow and green together, and the red and blue together. This will make the spindle drive run the motor at max speed when you push the button on the relay with the power on.

Slight problem though, when i start up the motor it makes a loud grating noise and vibrates whilst running, even though the spindle spins reasonably freely. Its not supported in a stable manner at the moment (uneven floor), so that could be contributing to the vibration.

I finally recieved a copy of the myford ml10 manual, which was pretty useless, but contained a few bits of info i wanted, namely how frequently i need to oil the various bits.

[mark kemble]

Hi

It sounds as if you have some swarf in the motor or the mounting is loose.

I am still using the original software and can drive it from there.
I attach some pics of the tool turret

[daedalus]

I have finally placed the order for all the tooling / electronics parts that i need, so hopefully everything will be arriving next week. I have ordered the recommended oil and will relubricate the spindle when it arrives and see if that is the problem. When i get some time i am thinking about removing the drive belt, as this should let me see if the problem is in the spindle or the motor.

- Its the motor, it doesnt seem to have any vents for swarf to have infiltrated, but i cant get to the back of it at the moment, as it protrudes into the area where the spindle is, and i cant get to the back. It is rigidly fixed, so that is not the problem. I have the nameplate data, so i guess its back to ebay to find a new motor, that or just put up with the noise and run this one till it packs up completely.

How much noise does yours make whilst running?

Thanks for posting the photos, yours looks in better condition to mine. Did you add the gas spring yourself, or did that come with it? mine has a fiddly folding steel tube to hold the lid open, which i really need to change.

Also i can see a bit of coolant tubing in the third pic, do you have a coolant system installed in yours?

[mark kemble]

hi
The cooolant is a mistery i understand that it worked by blowing air rather than liquid, as there is no return drain for any liquids this seems reasonable.

I have to admit it has been rather more trouble to make it work than i expected and as I do not have much spair time to play it has hung around.

The lathe came to me as you see it with that strut.
I am interested to see how you manage with making a new control for yours.

You can get a dc motor control from rs componants that will give veriable speed.