Boxford TCL160 missing steps.

[tay100]

This might be a bit long winded but please bare with me.

I bought a low millage TCL160 without software around 12 years ago with the idea of converting it, once i got hold of it the supporting documentation suggested that the machine was made in 1990 so was nt going to work with the current software without a major upgrade. So it sat around in my workshop for quite a few years gathering dust and i did a little bit of research into converting it but made no firm plans. Then not so long ago i managed to get my mitts on the relevant software so thought i was good to go but when i tried hooking up the PC it was the wrong connector on the back of the lathe. Long story short the machine had been updated, probably in the early 2000's and would operate on the latest software so i purchased the software from Boxford and thought i would be good to go, well yeaaaaah no :(

So to start off with i lubed everything up, installed the software, set my tool offsets and made a few test cuts. The initial cuts showed that the accuracy on the X axis was nt great but on the Z axis it was a total travesty ! Taking the belt cover off of the Z axis showed that there was an insane amount of lash in the screw, looking into the belt cover there was the remains of a thrust washer smashed into 7 pieces ! So, got a new thrust washer fitted, tightened the gibs up a little and did some more test cuts, it still was nt great at +/- 0.1 - 0.15 mm but it was good enough for the parts that i wanted to run so i just cracked on and thought i would get back to it at a later date when i had more time.

Just before Christmas i started to notice that it was getting a little further out, especially when doing a run of multiple parts without rehoming each time. Then i noticed when facing a billet that it would leave the tiniest little nub behind like the tool was nt on centre, the machine is fitted with a tool turret and had been fine up until then and sounds like it its being pushed back onto the pawl ok but i was starting to think that maybe that its not being locked into position right.

Anyhow this week i decided to pull the X and Z motors bearings and screws and see what i could do. Upon dismantling the bearing block for the Z axis i found another broken thrust washer on the inside of the bearing block this time ( i did nt check this one last time, just replaced the broken one i could see on the outside ) This one was still in one piece but had a couple of big chunks out of it. What could of caused this? Would it have been a tool crash by the previous owner? Anyhow checked over the screws, replaced the broken washer and then checked both axis by hand using a DTI and there was no appreciable lash, everything moves freely by hand so i put everything back together.

Next i fired up the PC, reset all of the tool offsets and ran a test part, if anything it was now worse than it was before ! Interestingly before parts were usually undersized on the diameter but on this test part it was oversized. Next i decided to run another part to see if the parts were at least consistently out, it got as far as facing the billet and i just hit the e stop, it had left around a 2mm diameter nub on the face of the billet. It was at that point that i walked away before i took a hammer to it

Sooooo, where to go from here ? Im starting to think that it might be electrical and not mechanical, although the boards were updated in the 2000's i suspect the motors are the original 30 yr old items, could it be that the magnets are degrading and the motors are loosing steps? How likely is it that they would all be buggered? It could be the drivers but again all 3 of them? The other thing that crossed my mind is the driver board not getting enough voltage / current and could that make the motors a bit limp?
Also does anyone know who is OEM on the stepper motors for these? There is a number on the back of each motor but a quick google brings up nothing. They are 4 wire bipolar motors and thats about all i know. The motor drivers are easy power GS-D200S which i think are 2-2.5A .

Im not very knowledgeable when it comes to things CNC so any ideas , any suggestions would be gratefully received because i have parts to make and right now and really need to get it back up and running.

[tay100]

Well i think i have ruled out mechanical or errant pulses from the PC. I jogged both axis from the front panel today and both motors were audibly " glitching " so i took the motor off of the X axis and jogged it whilst not connected to the screw and it can clearly be heard glitching / stuttering. My guess is that its the driver board or main board thats gone.
I will msg Boxford but im not holding out a lot of hope, they will just say send it for replacement boards and that aint going to be happening, not at their prices :(