My 1980 SL3B w/ YASNAC 2000G (SLD) is having an issue.

We just ran 1,000 Pcs. and we were having a intermitent problem. After the cycle the chuck would not unclamp. If you spun the chuck a few revs. by hand, then tried again, the chuck would open.

We got thru the job this way. Now, it's a different story. Production is a joke on this machine now. You have to mess with the spindle for a long while before you can get any response from it. The control tries to start the spindle but it just sits there waiting for the spindle to start. If you spin it by hand, sometimes it will kick in and the cycle willl run.

After the cycle, the chuck will not open without spinning it as before. As I said, you can get the spindle to come on via the program with manual spinning of the chuck after it sees the M03, sometimes not. Sometimes it may do it automaticly as it should, but hardly ever.

After the cyce, It seems to me that the control "thinks" the spindle is in motion. That's the reason it will not unclamp the chuck. But, with everything reset and the chuck clamped and cycle start pressed, something is telling the control to wait after M03 command. The control is not getting a confirmation of the spindle moving. That's why it just sits there and waits. Also, The manual spindle control on the panel is not working properly. I do have High and Low gears working and they switch out from each other as they should.

I know most of you guys will say SPINDLE DRIVE. But I don't think so. The spindle does run perfect when you CAN get it going.

I was thinking SPINDLE ENCODER. However the machine cut threads perfectly and CSS and such track perfectly.

I tried to trick the machine by disabling PARAMETER 40 (set to 0). This disables the M11 (chuck open) command and I thought that would help. It did not.

Could it be some kind of spindle motion sensor? I have never taken off the Plastic shroud that covers the spindle motor and encoder. I have looked inside there with a flashlight and I can see it has spindle encoder that was made when encoders ruled the world (HUGE).

Any experience here would be great

JohnnyTurn

On some of the older machines there was a clamp and unclamp switch / sensor at the rear of the spindle over the hydraulic cylinder. If you take off the plastic housing, you will see these two sensors ... they are in slots and are adjustable ... this needs to be done sometimes depending on how the jaws were bored or collet set ... the amount of stroke you used in the draw tube cylinder.

Another thing to check is the chuck clamp / unclamp light on the operator panel ... does it go on and off as it should? ... I think this is basically reading these sensors.

It sounds like the machine doesn't know if the chuck is closed or open ...

Another thing is that the lead from the sensor back to the cabinet may be broken somewhere along the way ... thus sometimes it works, sometimes it doesn't.

Hope this helps ...

Real World Machine Shop Software @ www.KentechInc.com

Thanks so much for the guidance here! I will check out the sensors.

And yes, the chuck light works as it should. I am thinking it may be a crunchy wire or the sensor needs adjusting/replacing.

I will let you know!

Thanks again!

JohnnyTurn