1. #1
    HI,

    Hoping for some advice. I came across a Beaver mill (VRP) a few years ago and as it was only 1 I bought it. It has Anilam crusader II CNC controls that don't work. The mill came out of a college and has apparently sat in a corner for many years due to a fault in the CNC controls.

    Roll forward a few years and it's in the way. I need to decide if I go with my manual Bridgeport or sort the beaver mill and sell the Bridgeport. To be honest I fancy having a cnc machine and the beaver mill is slightly heaver duty than the Bridgeport. So it comes down to how practical it is to upgrade the Beaver mill.

    I managed to get the machine tool tech's from work to look at it a while back. Conclusion was that there is an issue in the Crusader unit. Symptoms were refusal to jog in any direction. Once the override relay was frigged (piece of wood to hold it closed) all 3 axis would traverse. However the X axis would 'stall' after a few millimeters.

    I have stripped the unit and found no obvious poor soldered connections/loose connections. However to be honest the controller is ancient (cards are dated 1981), even if I get it working the link to send code to the machine is a parallel port, etc. In short I don't think it is worth making much effort with. From my limited experience with CNC it gets old very quickly typing in G code at a machine. I wan to be able to design in CAD (use atuoCAD), send to post processor and though to machine.

    So to me an upgrade of the controller is the right way forward.

    I have:

    x and y & Z - SEM DC servo drives (MT30E4's). 1.1 NM stall torque, max rpm 3600, 72 volts. Appear to be fitted with a tacho (7.5 volt per 1000 rpm)

    Drives - not sure - in a cabinet, assume Anilam units

    Encoders(?? position indicators) - fitted 0.01mm accuracy

    Already has ball screws

    So as a newbie what would you do?

    I like to do things 'properly'. So I think I want to do the following:
    1/. New CNC control, PC based.
    2/. I'd like to keep the current drives and servos, but be able to upgrade later if I had an issue.

    So my request is what would you do/recommend as solutions?

    Thanks,

    Adrian

  2. #2
    depends how good you are at electrical work.
    its original servo drives will be analogue- so to use those you would require a motion controller that supports analogue servo control
    ie galil, csmio a, etc these will work with mach3/4 (ive never tried mach4 yet) these systems can be fun to wire/ setup and tune for steady movement if you havnt a clue in motion control.
    however- as your motors are quite low torque and voltage you could keep motors and install new step/direction drives ( www.cncdrive.com make these that would be suitable and not over expensive)
    you could also go the cheapest / easiest method and change servos for stepper motors- this would work fine too.

    ive had success using uccnc via a galil controller to run analogue too - however depends on your skill level once again- and how much you want to spend to have it up and running.

  3. #3
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 16 Hours Ago Has been a member for 9-10 years. Has a total post count of 2,126. Received thanks 233 times, giving thanks to others 5 times.
    Your plan is reasonable, however the one component you really need to check, are the encoders actually encoders?
    Given the age of the machine, they could be resolvers (basically the analogue predecessor to digital encoders).
    You can get converters, but fitting new encoders is cheaper. A KFlop/Kanalog combo can be rigged to read resolvers, but it's not recommended, as there are a lot of variables that affect the final accuracy.

    Keeping the existing servos/drives should work well as long as they all still work. They would need a controller capable of analogue +/-10V.
    Some suitable controllers are-
    CS-Labs CSMIO-IP/A - Requires Mach 3 or 4.
    Certain Galil - Not that common for hobby use, as they are more expensive (and a bit more involved to setup)
    MESA boards - Main use is for LinuxCNC.
    Dynomotion KFlop/Kanalog - Can be used with Mach 3, or Dynomotion's own KMotionCNC software.

    I personally prefer Dynomotion, as it's the most adaptable, but that comes at the cost of needing to know a bit about C programming. I've also ditched Mach 3 on all but one of my machines, as I got fed up with it's glitches, but the built in wizards are very good if you want to do simple machining.

    However, the first thing I'd advise you to do, is create a list of all the inputs and outputs you'll require, as that will help comparing controller options.
    Also think about things you may like to do, as again it's easier to plan now, than retrofit later.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  4. #4
    My advice is to dump the servo's for AC brushless with Step/Dir drives and go with Centroid Acorn Controller.

    The Centroid control Software is built proof tried tested over many years and comes with built-in conversational Cam.
    The Controller is 4 Axis with Spindle encoder input and 0-10V analog Output for speed control. With more than enough I/O for Mill.
    http://www.centroidcnc.com/centroid_...ontroller.html

    You can buy AC Servo's cheap enough from China which will work fine. This combo will give you great machine with strong control that won't cost a fortune.

  5. #5
    Bloody hell Dean.: Welcome back from the dead
    ..Clive
    The more you know, The better you know, How little you know

  6. The Following User Says Thank You to Clive S For This Useful Post:


  7. #6
    Bloody hell Dean.: Welcome back from the dead
    +1
    Last edited by mekanik; 22-01-2018 at 09:16 AM.

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  9. #7
    Thought I would stick up a few pictures:

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    Thanks to those that commented. I'll knock up an I/O list and post next.

    Adrian
    Last edited by Breg90; 22-01-2018 at 11:31 PM.

  10. #8
    Hi,

    Few things in life got in the way of this. However eventfully I have knocked up a I/O/functionality list. See attached file.

    I find my self ending up looking at centroid solutions. What am I missing by not looking at others? Note this is a hobby, but I'd rather build something that is reliable and hopefully more saleable if I ever look to part with the mill in the future. I feel that the centroid solutions are more 'industrial' than the various MACH 3 (or 4) solutions.

    Any comments welcome.

    Adrian
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  11. #9
    id do as dean says- motors are small enough to replace with ac servos- ran in position mode.
    closed loop isnt required- as the loop is then closed in the drives (full closed loop systems are pretty expensive to set up)
    then choose a control capable of what you want/need. (governed by i/o number and working functions)
    personally id go with either uccnc - due to ease of setup and working features, or kflop as i know these both can be expanded to do exactly what you want reliably. (i dont know how much i/o upgrade etc can be done with acorn re modbus capability and so on- but this sort of thing is a must if you want perfect control over spindle/ mpg etc etc.

  12. #10
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 16 Hours Ago Has been a member for 9-10 years. Has a total post count of 2,126. Received thanks 233 times, giving thanks to others 5 times.
    First off, some comments about your IO list, starting at the top.

    I'd personally consider motorising the knee, but you need to consider if the quill alone will provide enough travel, by the time you factor in variations in tool height, and the size of work you're likely to do. DaveK has just done it to his, and uses it to compensate for tool length. I wouldn't be using the knee to provide extra travel for machining, because as you say, they're not designed to running up and down constantly, and certainly not at high speed.

    Scales are good for getting the best accuracy possible, but to use reliably, you really need to use a double closed loop. If you rely on just the scales, tuning servos reliably can be a major problem, as any backlash affects the loop, so can cause some very erratic results.

    Scales do not eliminate homing. Most scales are incremental output i.e they only output what direction they're moving, and how much they're moving.

    I'd personally stick with the VFD, as it gives more automated control. With a CNC, you want to be able to set it running, then walk away and ignore it, not have to go back to adjust things.

    So of the top of my head, to achieve that is going to cost a lot of money for a suitable controller.
    The only reasonably priced controller that I know that can do dual closed loop is a KFlop, but I think even that may struggle for the required number of channels.
    Say you run the motion using step/dir (the servo drives handle the inner closed loop), that is potentially 5 outputs.
    Then with the existing scales, that's 3 encoder inputs, plus the spindle, so 4 inputs needed.
    Now IIRC that potentially leaves one more step/dir output, and two encoder inputs (one of which you'd most likely want to use for a MPG). The problem is the step/dir channels share the same pins with the encoder inputs, but some of the step/dir outputs can be multiplexed across, so I think you can get a total combination of 12 step/dir and encoder channels.

    The reason I've not mentioned analogue, is the KFlop only has 8 encoder inputs, so if you use it to close the loop, 6 of those inputs would be needed for the 3 main axes alone. That potentially only leaves a combination of two step/dir outputs and encoder inputs . Although I think when used with a Kanalog, you can use the full 8 analogue outputs and 8 encoder inputs, and still get another 4 step/dir outputs.



    It might be worth considering the Centroid All-in-something DC controller. It's not cheap, but I'm pretty sure it's designed exactly for retrofitting this era of machine with DC servos, but I'm not sure if they can make use of the dual encoder loop. It would however save you the cost of new motors/drives, but then you're reliant on being able to get replacement motors/encoders should one fail.

    Failing that, you're into the realm of step/dir and/or closed loop without the scales, in which case, pick whatever software/controller you think will suit your needs best.


    And just realised, add a probe to your input list. They make setup far easier!
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

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