Mirac X position changes

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davejfowler
Posts: 16
Joined: Tue 12 Jul , 2016 12:33 pm
Hardware/Software: Denford Micromill 2000
VR 2.8

Mirac X position changes

Post by davejfowler » Mon 22 Feb , 2021 12:57 pm

I have a mirac lathe with an 8 position changer. Everything seems to work as it should. The only issue I have is that the Xposition changes over the course of a job. Usually on the plus material side so I have been working around it. Cutting from 50mm dia down to 8mm in 0.5mm cuts on brass the X will shift up to around 0.4mm its a little annoying but I have no idea what is causing this. I dont think the tool is slipping in the holder. Could the lead screw be slipping from the motor position? Any thought would be helpful! :)

Martin
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Re: Mirac X position changes

Post by Martin » Mon 22 Feb , 2021 20:42 pm

Have you lubricated the X axis recently?

davejfowler
Posts: 16
Joined: Tue 12 Jul , 2016 12:33 pm
Hardware/Software: Denford Micromill 2000
VR 2.8

Re: Mirac X position changes

Post by davejfowler » Mon 22 Feb , 2021 21:51 pm

Hello Martin, thanks for your note! I haven't done anything manually, though there is an oil feed which I assumed was lubricating the axis? Does this need to be done separately?

Martin
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Re: Mirac X position changes

Post by Martin » Tue 23 Feb , 2021 9:29 am

It may be worth running the lubrication until you see the oil coming out of the bottom of the X axis slide.

Just create a program that runs the spindle at 800rpm & move the X axis up & down with a M99 at the end to repeat.

The oil pump is activated when the spindle is running.

davejfowler
Posts: 16
Joined: Tue 12 Jul , 2016 12:33 pm
Hardware/Software: Denford Micromill 2000
VR 2.8

Re: Mirac X position changes

Post by davejfowler » Tue 23 Feb , 2021 15:46 pm

Thank you again. I've now run it over and over and I can see the slide is glistening with fresh oil. Still seems to happen. I can home between final cuts but I didnt think the axis could lose position like that. Is there possibly a coupling slipping?

davejfowler
Posts: 16
Joined: Tue 12 Jul , 2016 12:33 pm
Hardware/Software: Denford Micromill 2000
VR 2.8

Re: Mirac X position changes

Post by davejfowler » Wed 24 Feb , 2021 15:52 pm

Martin wrote:
Tue 23 Feb , 2021 9:29 am
It may be worth running the lubrication until you see the oil coming out of the bottom of the X axis slide.

Just create a program that runs the spindle at 800rpm & move the X axis up & down with a M99 at the end to repeat.

The oil pump is activated when the spindle is running.
Just another thought, are there bearings that position the screw axially? could they move in a housing or be worn?

Martin
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Re: Mirac X position changes

Post by Martin » Wed 24 Feb , 2021 21:14 pm

There is a Tab nut that tightens on to the bearings but because its on a slant it should drop down. It may be that the jib strip needs tightening to allow for wear.

Have you tried running with the feed rate turned down to 80%

davejfowler
Posts: 16
Joined: Tue 12 Jul , 2016 12:33 pm
Hardware/Software: Denford Micromill 2000
VR 2.8

Re: Mirac X position changes

Post by davejfowler » Fri 26 Feb , 2021 11:21 am

Great i will try to find that, and check the strips. I haven't adjusted them as the slide feels rigid, but maybe that's due to the weight.
Thanks Martin!

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