Author Topic: Reworking of a Denford Mirac CNC lathe.  (Read 2338 times)

Offline john11668

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Reworking of a Denford Mirac CNC lathe.
« on: July 19, 2023, 06:20:06 PM »
Hi all!

Please excuse me . I am a total novice on the forum although not without experience .
This project though is going to be a bit of a challenge.

Bought as a machine which "was working until recently".    Yea  Right!!

So  A Denford Mirac but no Denford software,
Clear evidence of  messing about to try and make it work. Several PCs had been tried .
Chap was running a small commercial CNC  operation  and had a number of working machines.
Said that it had worked but just stopped loading part  programs. But no evidence of recent working
Coolant had all been drained but was well dried up.

No evidence of any action when powered up , and I seem to remember a Denford dongle was needed to make it work and there was none .
E stop was a key switch and locked out with no keys .

For the price though it seemed reasonable  so it has become my winter project.
Collected from the midlands and brought home, but had to disconnect and remove the panel to get it in through the shop door.
It became clear that the monitor was duff but am going to get that "looked at" although a separate monitor works at the moment.
Decided that redeeming the Denford slave board was likely to be hard work  so opted to add a later PC with  Debian 10 having run my smaller lathe (Boxford TCL) on that.
 So have added 3 Bobs and  3 parallel cards ,  and had spindle , and axes working.
Am now looking at Turret and getting to the point of needing more help which is why I am here .
Bedtime now  so more specifics soon!

Offline awemawson

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #1 on: July 20, 2023, 02:23:58 AM »
Iíll watch this thread with interest having been there myself a few years ago.
Andrew Mawson
East Sussex

Offline john11668

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #2 on: July 20, 2023, 02:05:33 PM »
 
So a pic of the Mirac as I first saw it.


Was claimed to have been working until recently, at which point it stopped loading code. I have to say I suspect that it has not worked for quite a long time. lots of PC boxes came with it and a handful of hard drives suggesting there had been some unsuccessful trial and error attempts to make it work.
Got it home using a mateís pickup and successfully unloaded with a floor crane, but to get it through the workshop door the panel needed to come off (so all had to be disconnected)
Seen here looking forlorn after it was hoisted onto a trolley table. The ďDexionĒ version offered with the machine was just not going to do the job. And it needs to be on wheels for access to the panel when the job is done.
 





Panel was placed on the bench.
Whilst the Denford panel looks OK, I have no Denford software and am led to believe that a costly Denford Dongle could be needed to run Denford software.  I had already run a Boxford TCL machine using Linux so decided to do similar and Installed a PC with  Debian 2.8.4 and 3 parallel ports
Then removed the Denford slave board , (reasonable offers considered)   to make room for the new kit which includes 60v drivers ,  3 BOBs  and a 0.4Kw VFD.
 
 


A mate has done similar with a Denford Cyclone, adding a turret control board designed by a colleague, and sourced from China and he has made a successful conversion. His turret motor had been goosed so he had converted his to a stepper motor drive.

 We compared notes and it was decided to first try the existing turret motor and see if it worked.
 All of the turret connections are now identified and tie up with the manual for turret wiring of a six station model.
We tried to run the motor (free of the turret) using the 0.4 Kw VFD.   It stuttered and quickly overheated.  Tried another VFD which did similar, yet the windings check out and there are no signs of damage, so am now puzzled. The turret data plate is lost but it does look like your RH80 model Andrew.
So the question is now whether the motor is goosed, or do we need a beefier VFD??
What is the rated power of the turret motor and what VFD should drive it .
What did you use Andrew?
« Last Edit: July 21, 2023, 04:20:58 AM by john11668 »

Offline john11668

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #3 on: July 20, 2023, 02:10:39 PM »
post deleted
« Last Edit: July 25, 2023, 06:10:11 AM by john11668 »

Offline awemawson

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #4 on: July 20, 2023, 05:19:29 PM »
Itís an awful long time ago so memory is hazy, but Iíd expect that I put all the details in my thread, I do tend to bore people with the minutiae !
Andrew Mawson
East Sussex

Offline Spurry

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #5 on: July 21, 2023, 04:05:58 AM »
.... I do tend to bore people with the minutiae !
Au contraire. Your posts are always helpful, informative, and a very useful point of reference.
Please continue in the same vein.  :thumbup:
Pete

Offline john11668

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #6 on: July 23, 2023, 03:09:22 PM »
Used a beefier VFD and now have turret motoring .
In the absence of a Slave board we know to be working, we are adding a dedicated turret board.
We know we have to motor the turret past the required station then back into the lock position and that function is proven.  Board should be fitted this week  then hopefully make some chips.


Offline john11668

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #7 on: July 25, 2023, 05:10:33 PM »
Itís an awful long time ago so memory is hazy, but Iíd expect that I put all the details in my thread, I do tend to bore people with the minutiae !

Cant see anything there Andrew.  Would it be possible for you to check please ??

Offline awemawson

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #8 on: July 26, 2023, 10:52:12 AM »
Remind me what you were asking - the relevant post seems to have been deleted. Bear in mind that I no longer have the machine so can't 'look see'
Andrew Mawson
East Sussex

Offline john11668

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #9 on: July 26, 2023, 01:37:01 PM »
I deleted the irrelevant post , about coming back after dinner

The question was in the prior post
"What is the rated power of the turret motor and what VFD should drive it .
What did you use Andrew?"


Offline awemawson

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #10 on: July 26, 2023, 03:03:08 PM »
I remember that there were two VFDs - one for the main spindle and one for the turret.

If you look the first post in my orignal thread they are both pictured in "Back Home #3" so not difficult to find. One looks to be a Mitsubishi 750 watt and the other seems to be a proprietry which iirc finally gave up the ghost with excessive leakage to earth and I replaced it with a cheap chinese ebay special but I'm certain they were detailed in later posts but can I ask that you go and look for yourself.

Sorry to be grumpy but I've spent the last week between the doctors, and the A&E departments of two hospitals and an eye hospital so my tolerance level is somewhat reduced.

Andrew Mawson
East Sussex

Offline john11668

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Re: Reworking of a Denford Mirac CNC lathe.
« Reply #11 on: July 26, 2023, 05:29:07 PM »
Remainder of the thread seems to be about cosmetic stuff.  I will look agaain when I get the opportunity.
I take it there are no others on here familiar with Mirac