Servo Driven 4th Axis for CNC Mill

Gallery, Projects and General > Project Logs

<< < (23/39) > >>

John Stevenson:
Andrew,
So sorry I didn't know. It's always a wrench and you say you won't have another but you always do.
We are on No's 9 and 10 of the Old English Sheepdog rescues.

But No 9 is doing my head in, play for England 25 hours a day, mind you if truth be known he plays better than England............

Pete W.:
Hi there, Andrew and John,

This is definitely :offtopic: but here goes,

This is 'Unity', she's a retired guide dog, twelve years old and has been with us just two years and one month.

She's successor to our previous GSD who we lost at six and a half years of age, it took us a while to get over that loss.

We meet several Viszlas while dog-walking in local venues, one of them is wire-haired.

awemawson:
I'm pleased to say there has now been lots of progress on the 4th Axis.

I decided that the side exiting wiring was a no-no, and that the use of the original SEM termination box was messy, so I re-made the motor box with rear exiting cables that have to emerge 'upwards' to avoid fouling other things. I also gave the mechanics a lick of paint, that no doubt will all be removed in use !

awemawson:
I then wired up the various relays needed:

a/ 4th Axis enable
b/ 4th Axis brake
c/ 4th Axis ESTOP

Wired up the servo card and finished off the external termination box

awemawson:
At this stage I was then able to start testing. The system worked, amazingly, but I couldn't get a decent speed out of it without generating 'Gross Positioning Errors' Fairly obviously the servo card needed tuning, and some parameters tweaking in the control. However the good bit was that the gearing and encoder interface was working correctly to give me 360 degrees for a full turn as it should.

I went through the Bosch manual MANY times following their procedure, and try as I might couldn't get the main servo motor spinning more than about 700 rpm without errors - it's max speed is 3100 rpm and I'd initially set it up to max on the servo at 2000 to be on the conservative side.

Many people offered help, both from this forum and others and I thank them profusely, but the break through came the other day, when by chance I was put in touch with a local chap who had installed this type of servo card many years ago.

Long story short - he came round yesterday, and after four hours of tweaking, un-tweaking and head scratching we got it to a very acceptable performance. Servo motor is now reliably able to spin at 2500 rpm giving 2500 degrees a minute on the table.

So to celebrate, last night and this morning I made up the swarf cover and am ready to put it on the machine table and try it for real. That won't happen immediately due to family commitments

Navigation

 Message Index

Go to full version