Oh Blimey I bought a CNC Lathe !!!!

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Leblondmakino:
Yes defo sounds like a reference position issue on that axis..should be a way of re zeroing the encoder or it could be a soft limit setting that needs changing or re setting..

awemawson:
Yes it was a referencing issue preventing the V axis moving towards the headstock end. Had a good look with a torch to find the proximity sensor and it's associated lump that it detects - can just see it looking down an access panel at the tailstock end. This showed it was set to reference at the extreme rightwards travel, and I was thus given the confidence to fast (not very!) travel it to close in jog mode then do a final approach in reference mode. Lo and behold the V axis value was then set to a sensible figure (it had been at something like -24000 mm) and I could then move the axis in jog mode in both directions.

All axis reference points are the same mechanically - a three terminal magnetic proximity sensor on a bracket looking for a simple cylindrical collar that is fixed with a set screw on a shaft parallel to the axis motion. Seems crude, but I suppose that the sensors are very repeatable.

I think that there is still a 'funny' to solve on the axis servo drivers - the absolute axis position is supposed to be retained on power off, and on two axis it is being lost despite the battery measuring ok, and also having been changed anyway. Not the end of the world if I cannot solve it - just means I'd have to re-reference after a power down.

Next thing to investigate is the tool turret - see if I can get a bit of time later today.

awemawson:
Today was one of those days when circumstances stop you doing things :( We seemed to have an endless stream of visitors all morning expecting teas and coffees - don't these people realise some of us just need to slink off to the workshop! Seriously though it it nice to have visitors.

Eventually I managed to get to the coal face and look at this turret issue. Turns out no way is the tool turret going to turn unless the safety cover is closed and locked. There are three digital inputs for 'door open' 'door closed' and 'door locked' and although the 'door open' one is toggling as the door moves, the others don't. What is supposed to happen is that a relay latches on for 'open', is released as the door closes, and another relay latches on for 'closed'. When the controller sees the 'closed' state it fires a solenoid bolt, and a feedback contact for this bolt generates the 'locked' status. The 'closed' relay is briefly clicking over but not latching on.

I strongly suspect that the latch circuitry was originally routed through the bar feeder, which I don't have, so I'll probably end up having to link it out. Not proved yet so something for tomorrow when I get back from taking four pigs on their last journey.

Investigation was greatly hampered by having all the relay logic at the back, and the safety sliding cover at the front, so you cannot see whats going on as you slide the door :( Eventually solved this conundrum using the 'Indian Rope Trick' . I tied a length of rope to the door handle, and passed it right round the machine and back to the handle. Now I can slide the door from the back. :clap: :clap: A low tech solution to a high tech problem.

awemawson:
My handy piece of rope has let me at last diagnose the door relay logic fault - we now have 'door open', 'door closed' and 'door locked' relays all doing what they should do, and about time too, I've been all round the houses on this one. In the end it proved to be a 'normally open' contact that was never closing - had to pull the relay (M1-K8 for the record) and dismantle and clean its contacts as I had no spare for that variety.

Now the door lock solenoid fires whenever an axis is moving or a spindle is turning - all clever stuff. Also now the jogging 'rapid' button works when the door is closed but is inhibited when it is open.

So on to the the Tool Turret. It is saying 'Turret is not locked' at the moment. This is the tool turret:

lordedmond:
well done it will not be long now , it does look as if the major hurdles are behind you now

Stuart

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