MAHO 1000 c CNC retrofit/rebuild
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    Default MAHO 1000 c CNC retrofit/rebuild

    Now here is the deal, a friend of mine has gotten this old CNC mill for about 2500 usd, given it's 8 tons of weight is not that far off from its scrap value if disassembled.
    now the problem is this, the mechanical parts, axis etc are working , the three servo motors are in ok condition, the main spindle motor is also working.
    the cnc doesn't have it's original controller box only the power supply and the individual axis drive/motor power boards of which there are three.

    Since I haven't gone into much deeper reading and have yet to see the cnc itself fully my question then is this, is it possible to get a main controller (modern one with all kinds of connections ) and have it work with the original motor drive blocks and motors or would it be much easier to simple get a new controller together with the axis motors and their drive units and just keep the spindle motor original since that doesn't have any position readouts etc and is just a motor.

    the original motors on this cnc are DC permanent magnet servo motors with the main spindle motor being rated for 14kw and each of the axis servo motors about 2/3 or something kw.
    purely in physical terms they are quite large and heavy.

    they are manufactured by Indramat which is a German company
    indramat mdc 9.30b - Google Search

    here is their model name.

    Ok I guess i'll leave it here for my first post and let's see some of your answers.

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    Back in the 80s and 90s when I was doing field service, myself and the other field service techs called the Indramat drives "Laundrymat" drive because we had concluded they were better suited to power a washing machine than a CNC machine. You may have better resources than we had in the US as there was almost no factory support here in those years.

    A common problem on old Maho machines is bad wear on the keeper plates for the "knee". They were undersized for the load they carried (particularly on the models with the built in rotary table) and wore quickly which allowed the knee to droop.

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    well my main concern is what to do with the servos, I mean if the existing servos and their drives can be coupled with a modern controller board then all is fine but if they can't then one needs to add to the existing cost new servo motors with new servo drives.

    from reading I concluded that in our time stepper motors are used mainly and they don't require a feedback mechanism. And even if servo motors are used they now come AC instead of DC , I assume for ease of operation, but can a stepper motor conversion be done on such a bulky cnc machine?

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    Quote Originally Posted by artis View Post
    well my main concern is what to do with the servos, I mean if the existing servos and their drives can be coupled with a modern controller board then all is fine but if they can't then one needs to add to the existing cost new servo motors with new servo drives.

    from reading I concluded that in our time stepper motors are used mainly and they don't require a feedback mechanism. And even if servo motors are used they now come AC instead of DC , I assume for ease of operation, but can a stepper motor conversion be done on such a bulky cnc machine?
    IMO DC servos are light years ahead of steppers. Open loop vs closed loop. Long before I took a step back like that I would look for another running machine or one I could fix. I don't know anything about this machine but I do know that pretty much any industrial closed loop control is better than a open loop stepper system......IMO I own both, steppers are cheap and easy to implement......that's about the only advantages I can think of. Any time I use something with steppers its always in the back of my head wondering if it has lost steps and actually knows where it is.

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    Quote Originally Posted by artis View Post
    .....from reading I concluded that in our time stepper motors are used mainly and they don't require a feedback mechanism. And even if servo motors are used they now come AC instead of DC , I assume for ease of operation, but can a stepper motor conversion be done on such a bulky cnc machine?
    Steppers are crap and have no place in an industrial CNC. They are used by the hobby crowd for low cost, low grade machines.

    AC servos primarily replaced DC for reasons of reduced maintenance and better reliability.

    Your Indramat drives are analog units. Most retrofit CNC controls could drive them. Something PC based like LinuxCNC with appropriate motion control board would probably be your best option to get the machine going again if low hardware cost is important.

    If you place any value on your time it won't be worth it. If it is a hobby project and something to help pass a cold winter.....

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    Forget about steppers, you dont want to mess with that. Original servos and drives can most likely be used. Check out Dynomotion Kflop/Kanalog controller. This will let you control anything you could possibly want with the machine and will be very reliable. Im using it on a Fadal 4020 and really like it.

    It will be a ton of work. Do you really need this type of machine? You may be better off getting a better type of machine if your going to put that much time/money into it. A typical VMC with enclosure and tool changer will be much more useful for most work.

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    well in fact the guy has already bought a dynomotion kflop controller that sits inside the place where the old original controls once used to be, I will only really check on the machine today but from what I know so far it has all the original equipment except for the controller, so if one can make the kflop controller work with the original drives then all is fine.

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    So today I sorted out all the incoming three phase power, attached it to the large transformers, also delivered power to each of the three servo drives (left out the main spindle drive for now) two of the drives show green led lights and their motors seem to move the third shows a red light indicating a problem which I will try to sort out.
    basically I have to still attach the taho readouts and brake solenoid to the servo drives in order for me to be able to move the servo motors normally.

    if anyone has some schematics or something it will be greatly appreciated.

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    Quote Originally Posted by artis View Post
    well in fact the guy has already bought a dynomotion kflop controller
    Good choice, your off to a good start. There is a dynomotion forum on the zone, the owner Tom posts regularly and will be a great help with any questions about the conversion. You should start a build thread about the machine over there.

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    Well I have gotten all three servo drives to function , at least to some degree, attached the tacho gens to the drives, also the DC solenoid wires for the release of brake on each motor.
    impossible to find any info on the internet but so far my best bet I attached a 9v battery to two of the input terminals that seem to drive the ic regulating the output thyristors and when Ii flip the battery +- to the input terminals the servo motor goes either one way or the other, so far so good, then as I disconnect the wire that goes to both the DC brake solenoid + and input RC/12 on the drive (which in the german instructions is labeled as "controller voltage") I get the servo motor on each drive to stop and the brake is engaged at the same time.
    the thing I couldn't control is the RPM of the motor in each direction as it seemed to go very fast, maybe I should try out with a lower voltage and a potentiometer.



    PS. what do you mean by the zone?

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    Quote Originally Posted by artis View Post
    PS. what do you mean by the zone?
    just google search "cnc"+"zone". Sheesh

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    Quote Originally Posted by artis View Post
    ......the thing I couldn't control is the RPM of the motor in each direction as it seemed to go very fast, maybe I should try out with a lower voltage and a potentiometer....
    Those drives are analog input. -10V-0v-+10V input. 0V=0speed and 10V positive or negative =max speed and direction control. Most retrofit type CNC controls are able to provide this signal type.

    You will definitely be better off at the "zone" as you work through your machine.

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    Quote Originally Posted by artis View Post
    Well I have gotten all three servo drives to function , at least to some degree, attached the tacho gens to the drives, also the DC solenoid wires for the release of brake on each motor.
    impossible to find any info on the internet but so far my best bet I attached a 9v battery to two of the input terminals that seem to drive the ic regulating the output thyristors and when Ii flip the battery +- to the input terminals the servo motor goes either one way or the other, so far so good, then as I disconnect the wire that goes to both the DC brake solenoid + and input RC/12 on the drive (which in the german instructions is labeled as "controller voltage") I get the servo motor on each drive to stop and the brake is engaged at the same time.
    the thing I couldn't control is the RPM of the motor in each direction as it seemed to go very fast, maybe I should try out with a lower voltage and a potentiometer.



    PS. what do you mean by the zone?
    Thats great, at least you know the drives and servos are good. A 1.5v battery would be safer as most drives are +/-10v. A resistor is normally used in series to prevent damage if you put voltage to the wrong point, but sounds like you got it right.

    Yeah google cnc and zone and you will find another forum with more info about your retrofit. Id post a link but its blocked. Not many people on here discussing this type of stuff.

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    Look at this thread:

    Contest for the most insane member (They will be a Maho owner)

    IIRC from this thread, an off the shelf Heidenhain control will run your machine. You will, of course, have to set it up with umpteen parameters and programming....

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    If I had this machine I would pick up a Siemens or Heidenhain control and put it on. Analog drives are not a big problem, and what is nice about those Indramats is that the tuning of the drives was done on the drives themselves rather than using parameters in the control like Fanuc. Also the E-Stop circuit on that mill is likely external to the control which makes it much easier to have the machine up and running safely provided it is still used as it was originally intended.

    Both Siemens and Heidenhain have quite a bit of the PLC filled out for machines similar to this by default. If you do a control retrofit with a high quality industrial control you will have something that will be of much more value in the end. Not only will it work quite well but the knowledge you gain will be applicable to these controls which can be very valuable too. They both offer lower cost controls for exactly this type of application.

    Good luck with your project.


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