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  1. #61
    Jess's Avatar
    Lives in Leamington Spa, United Kingdom. Last Activity: 08-06-2015 Has been a member for 2-3 years. Has a total post count of 35. Received thanks 2 times, giving thanks to others 0 times.
    I think if the motors are working (at a guess, they probably are), then I think they'll be just fine.

    I'd emphasise the 'budget for' though; worst case, you might have to fork out, but obviously, every penny you don't fork out, is a penny you can spend on your vices (and clamps, endmills etc.,)

    The problem with the stock electronics is that it's basic (eg., the drivers are probably only half-stepping etc.,) and conservative (voltages are lower than necessary etc.,). So, it's not going to run as smoothly or as quickly as it otherwise could.

    Having said that, it's also quality stuff; so it's often worth flogging the bits you don't need on eBay, especially if they're working - last I looked the motion control and driver boards seemed to fetch a decent price.

    On my very small Denford, I've only replaced the stepper drives and DC supply (the original was part of the original drive board). I've been able to keep the door latches, e-stop, various relays, spindle control board, transformer etc., The main reason I replaced the drive board was actually that it was a real pain to interface to. After a couple of months of 'is it the drive or is it the BOB or is it my wiring' hassle, I broke down, bought a Gecko and had the machine working (with LinuxCNC) in a couple of days.
    Last edited by Jess; 02-06-2015 at 06:40 PM.

  2. #62
    Quote Originally Posted by Jess View Post
    I think if the motors are working (at a guess, they probably are), then I think they'll be just fine.

    I'd emphasise the 'budget for' though; worst case, you might have to fork out, but obviously, every penny you don't fork out, is a penny you can spend on your vices (and clamps, endmills etc.,)

    The problem with the stock electronics is that it's basic (eg., the drivers are probably only half-stepping etc.,) and conservative (voltages are lower than necessary etc.,). So, it's not going to run as smoothly or as quickly as it otherwise could.

    Having said that, it's also quality stuff; so it's often worth flogging the bits you don't need on eBay, especially if they're working - last I looked the motion control and driver boards seemed to fetch a decent price.

    On my very small Denford, I've only replaced the stepper drives and DC supply (the original was part of the original drive board). I've been able to keep the door latches, e-stop, various relays, spindle control board, transformer etc., The main reason I replaced the drive board was actually that it was a real pain to interface to. After a couple of months of 'is it the drive or is it the BOB or is it my wiring' hassle, I broke down, bought a Gecko and had the machine working (with LinuxCNC) in a couple of days.
    Thanks. Sounds reasonable. Does anyone have quick numbers for the cost to do this? Considering there is a converted (Mach3) Triac on Ebay for 3250, how much cheaper should I get this to make it worth while?
    Last edited by Chaz; 02-06-2015 at 08:26 PM.

  3. #63
    Jess's Avatar
    Lives in Leamington Spa, United Kingdom. Last Activity: 08-06-2015 Has been a member for 2-3 years. Has a total post count of 35. Received thanks 2 times, giving thanks to others 0 times.
    Someone might have better numbers if they look for the actual specifications/cheaper suppliers/use a slightly larger envelope for calculations, but I'd guess you can probably easily spend 500-800 converting one depending on the parts you use even if you're 'just' replacing the stepper drives and you've got a few of the things you'll need.

    These aren't recommendations as I've not personally used these - I'm just using the prices as a guide:

    Geckodrive G213V drives (80V, 7A digital step drives) are $166 each, and an Ethernet Smoothstepper is $180. So, three drives and motion control board run to $678; once you get it shipped and Customs and Excise take their chunk of flesh for Duty and VAT, you might as well assume that that figure is already in GBP. Alternatively, you can get 80V, 5.6A drivers from Zapp Automation (a UK supplier) for 84 each, which with the smoothstepper and shipping sounds like it comes out to about 450.

    On top of that, you might need breakout boards and you'll definitely need various cables, wires, mounting brackets, a mounting plate for all the gear and many, many cups of tea. So, yes, it's very easy to spend more than you meant to getting it working, so it's definitely worth doing some proper working out.

    It gets rather difficult comparing the value of Triac models; one might have an automatic tool changer, another might be fully enclosed, another might be 13 years newer etc., If we're comparing against the one on eBay with the lurid guards, then that seems to have a coolant system installed. These are all potentially useful, but their value to you will vary depending on what you're doing (and some are easier to retrofit than others!)

    What power supply does a Triac mill require BTW? If it's more than you can get from a standard 13A mains plug, you could get a nasty shock in the form of a bill for installing one of those circular sockets (unless you're lucky enough to already have the right one).
    Last edited by Jess; 02-06-2015 at 11:33 PM.

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  5. #64
    Look for denfordata on google to get the mill details as well as lots of info from people who have probably converted them to Mach 3 and / or modern drivers etc. for guidance I spent less than 200 on new drivers, a BoB and smps to get my Novamill working, using the original motors. All the electronics from China via eBay, 2m542 drivers. Psu is 36volt. There were no electronics at all with my mill so also had to use a KB electronics motor drive I already had, but you can use the one in the mill if it's working. Caution however, if it's a dc motor thyristor drive it is NOT isolated from the mains and you will need an isolating circuit to link the drive to your BoB.

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  7. #65
    Thanks both. Good info to consider.

  8. #66
    Or you could use:
    -3 x Leadshine closed loop steppers 3nm around 200euro each kit shipped
    -1 x PoKeys57CNC /still have not tested it but price and what offers seems unbeatable by any board/~150euro shipped

    and for affordable price have a closed loop machine ethernet driven. thats what my calculator says , i spend all last night in similar doubts and researching options for quality versus price

    PS. I found some new similar drives for around 160 so shipping could be combined like 3x160+50, which is even better. Not to speak of that understate the value is a must nowadays
    Last edited by Boyan Silyavski; 03-06-2015 at 09:36 AM.
    project 1 , 2, Dust Shoe ...

  9. #67
    Quote Originally Posted by silyavski View Post
    Or you could use:
    -3 x Leadshine closed loop steppers 3nm around 200euro each kit shipped
    -1 x PoKeys57CNC /still have not tested it but price and what offers seems unbeatable by any board/~150euro shipped

    and for affordable price have a closed loop machine ethernet driven. thats what my calculator says , i spend all last night in similar doubts and researching options for quality versus price

    PS. I found some new similar drives for around 160 so shipping could be combined like 3x160+50, which is even better. Not to speak of that understate the value is a must nowadays

    Thanks. For closed loop, you need some form of encoder? How is this fit to the standard motors?

  10. #68
    The motors come with encoders already. Its all in one, they call it Easy Servo. It seems on paper better than steppers, cause due to the precise control the steppers loose power at higher than normally RPM.

    I would say with hand on my heart that IMO for metal working closed loop is a must. Not that steppers will not do it, but my mind feels easier that the machine is where i tell it to be :-)
    project 1 , 2, Dust Shoe ...

  11. #69
    Quote Originally Posted by silyavski View Post
    The motors come with encoders already. Its all in one, they call it Easy Servo. It seems on paper better than steppers, cause due to the precise control the steppers loose power at higher than normally RPM.

    I would say with hand on my heart that IMO for metal working closed loop is a must. Not that steppers will not do it, but my mind feels easier that the machine is where i tell it to be :-)
    Understood. Thanks.

    Just found a Triac VMC that looks like a worthwhile project. Depends on the final price though.

  12. #70
    Jess's Avatar
    Lives in Leamington Spa, United Kingdom. Last Activity: 08-06-2015 Has been a member for 2-3 years. Has a total post count of 35. Received thanks 2 times, giving thanks to others 0 times.
    Quote Originally Posted by JohnHaine View Post
    Look for denfordata on google to get the mill details as well as lots of info from people who have probably converted them to Mach 3 and / or modern drivers etc.
    Yes, everything should posted somewhere on Denford's forums; might need some digging though!

    Quote Originally Posted by JohnHaine View Post
    Caution however, if it's a dc motor thyristor drive it is NOT isolated from the mains and you will need an isolating circuit to link the drive to your BoB.
    Given the simplicity of the circuit needed for this (in the common PWM output case, it's one opto-isolator, two resistors and a capacitor), I'd probably avoid a breakout board that has a non-isolated 0-10V spindle output on the basis that it's been overly cost-reduced.

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