Novamill tool turret problem

All info relating to the Denford NovaTurn CNC lathes

Moderators: Martin, bradders, Steve, Mr Magoo

Post Reply
mitip
Posts: 6
Joined: Mon 08 Aug , 2016 16:46 pm
Hardware/Software: Novaturn Vr turning

Novamill tool turret problem

Post by mitip » Thu 11 Aug , 2016 19:27 pm

I bought a nice condition Novaurn that was sold to me is completed working. I saw it work well from cold. When I finally got it commissioned and tried to use it I found that the turret motor was chattering very noisily on tool number one. Note I have not personally tried adjusting the ratchet pawl when it is not moving. But it is possible that the previous owner did and caused damage. It seemed to find an intermediate position on tool change where it was stuck. The toolpost end would rotate a few degrees but seems slightly tight when moving it by hand, as if the bearings were over tightened. I'm really not sure about the gearbox it may have stripped teeth, I'm not sure.
So I have little choice but to take it apart, I found the appropriate exploded view drawings on this forum and have been studying them. As far as I can see that by disconnecting the turrent motor from the connector in the end plate PCB by releasing two wires means the motor could come free,. But I have loosened the four screws in the motor will not lift, and I've tried very gentle persuasion. I have loosened the nut the other end and there's no way I can get the bearing out gain access that way, this is assuming that the motor should just slide out because it's got a metal pin sitting in socket. If that's not the way it's done could somebody let me know? When I look inside the connector end I can see the encoder plate as a silver pattern on a rotating disc for turret position and I assume some sort of IR position recognition based on simple logic due to the shape. I have marked the angle of the turret relative to this encoder plate using the cross marked on the shaft and seen it aligns with certain edges on the encoder plate. Is it okay to remove that plate? Can I get it back on accurately? I noticed there is a castellated nut putting pre-tension on the angled roller bearings, is very torque setting for that? Is there a special tool to undo it, I know I can make one but if it's not too expensive I will buy it?

If the motor doesn't come out the top how else do you get it off? If it's stuck what choices do I have? I have now lost all my tool offsets so had to go back to square one on that, is hoping to avoid that as the previous owner had set it up very nicely. Too late now. I have read all posts about people taking these toolposts apart, how do you do it.? It has what looks like a simple max on DC motor inside heat sink. I know such motors are not that expensive on the Internet, are tempted willing to share their specification, same with the gears in the gearbox. If the gearbox is not proprietary part that made by Max on I have dealt with them before and probably could source gears the gearbox or find a 60 to 1 reduction gearbox on its own. Any thoughts on that? I have been working my way through VRturning and quick turn, they seem perfectly adequate for my uses but I wish the DXF importer were better, it doesn't work well from many of my four CAD packages, mainly because the way they describe the circle is no use I think. It has to be polylines so I use £30 DXF the polyline converter I found on the Internet, be very nice if this were built in.
But in principle the way VR turn works seems adequate apart from the inability to put a neutral tool in the tool post, i.e. define something that will cut with both faces of the 35° neutral insert, one used for profiling. Can you add profiling? Would it take a lot of code to make the software use the same tool for left and right hand finishing? So that you can profile complex 3-D surface and get a smooth finish.
I've also been told about fuses in the control box but I looked at the toolposts PCB and the fuse is good. When the motor was stalled toolposts got very hot and I turned it off before it got too hot but there is a distinct smell of blue smoke coming from it meaning it's got pretty hot. Would that happen if it was pushing 12 or is it 24 V in and nothing was happening? I know you reduce the voltage for the return locking function is there a way to check this is working properly? The machine will home at high speeds but will not jog except very slowly once the tool change button has been pressed, it puts up the spinning wheel of doom and I have to use task manager to get out of the software.
Maybe I should add this is very urgent, I am actually wanting to use the late on a major project.

DavidB
CNC Expert
CNC Expert
Posts: 111
Joined: Tue 19 Oct , 2010 16:06 pm
Hardware/Software: Triac

Re: Novamill tool turret problem

Post by DavidB » Thu 11 Aug , 2016 22:01 pm

I'm not sure whether the Novaturn toolchanger is the same as the Orac one so maybe you could post a pic or a link to the details of its' assembly. The Orac one is here http://www.denfordata.com/downloads/for ... s-list.pdf page 33 and I have had mine apart recently and re-assembled it with new bearings and a bit of fettling. Post here /viewtopic.php?f=43&t=4972 . The internals don't look like they would wear but the gearbox was known to be weak and it had to be replaced but I found a seller on ebay selling the correct box so I bought one and modified it with the drive pin and all OK so I bought a few extra as spares. Maxon still listed the gearbox online at a decent price so ebay is not the only option.

Martin
CNC Guru
CNC Guru
Posts: 1749
Joined: Fri 24 Feb , 2006 17:09 pm
Location: Brighouse

Re: Novamill tool turret problem

Post by Martin » Fri 12 Aug , 2016 10:23 am

The motor & gear box should slide out once you have removed the 4 screws. You may need to try getting a screwdriver behind the gear box to help it out.

Don't forget the motor wires run through the gear box so it may be easier to remove then heat sleeve & unsolder the 2 wires from the motor.

Post Reply