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  1. #11
    there are lots of things like this over ebay

    http://www.ebay.co.uk/itm/CNC-AC-Ser...gAAOSwMgdXyS7x

    and even cheaper stuff??

    http://www.ebay.co.uk/itm/EU-Stock-N...4AAOSwoBtW58KV

    I don't mind spending a few quid to get good results

  2. #12
    Quote Originally Posted by andy_con View Post
    link me up...
    usedparts-pk He is very decent seller from Korea. Check his listings for servo motors and drives and combos. Normally he will have nice 400w packs. Most of all he checks them, have seen videos, has 100% feedback and can combine for you stuff for better price even, outside of ebay also.
    Last edited by Boyan Silyavski; 24-03-2017 at 08:55 PM.
    project 1 , 2, Dust Shoe ...

  3. #13
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 3 Days Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,908. Received thanks 360 times, giving thanks to others 8 times.
    Quote Originally Posted by andy_con View Post
    there are lots of things like this over ebay

    http://www.ebay.co.uk/itm/CNC-AC-Ser...gAAOSwMgdXyS7x

    and even cheaper stuff??

    http://www.ebay.co.uk/itm/EU-Stock-N...4AAOSwoBtW58KV

    I don't mind spending a few quid to get good results
    750W would be overkill for a Triac. I'd aim for 200W, or maybe 400W.

    The second link is actually a closed loop stepper system. Technically it is servo system, however it won't have the same performance as what's more commonly referred to as a servo system.

    I had been hoping DaveK would of chimed in with his views on the generic Chinese servo systems, but I guess he's too busy playing with his new toy...
    Last edited by m_c; 24-03-2017 at 09:03 PM.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  4. #14
    Hi all,

    I got my servo's from AliExpress direct from China, they are fitted to a Bridgeport mill(ex manual style machine) I got 700W on X&Y and 400W on Z.

    Having only used steppers until this job, i was not expecting them to be as good as they were as the Nm figures do not compare with steppers at all. I used a CSMIO IP-A with 10-0-10v control.

    The issues i had/have are all tuning related really - the manual i was sent by the guy was in strong Chinglish so not really much use to a beginner like me. To get a really good tune i am convinced i need to alter the parameters in the drives but cannot do this.

    The tuning in CS Labs plugin is all i have so worked with that. It is a time consuming process, forget the auto-tune ;) Apart from a slight resonance on the Z drive I have it running really well now, very little following error and good acceleration, top speed is pretty low at 2500mm/min but this is only an old Bridgeport so no point in flogging her to death. Acceleration was more important to stop corner-rounding in Mach 3's trajectory planner.

    I must admit that i had the 400W on the bench to play with and even running at maybe 5 rpm i could not stop the shaft rotating no matter how hard i grabbed it, the torque is phenomenal and start / stops at speed are sharp enough to make the motor jump off the bench!

    I could probably have fitted smaller motors on the mill, they have 2:1 reduction drives but this size seemed a good price :) I think they were about £400 for 700W with drive and 5m cables.

    I would love to fit them to the plasma cutter, may do one day.

  5. #15
    Quote Originally Posted by Davek0974 View Post
    The issues i had/have are all tuning related really - the manual i was sent by the guy was in strong Chinglish so not really much use to a beginner like me. To get a really good tune i am convinced i need to alter the parameters in the drives but cannot do this.
    Ok I've been watching and stayed out of this until now because don't have any experience with Triac's or there power requiements but need to make this clear to defend chinese servos.
    Dave I'm not having a go at you so please don't take it this way just want to point out for sake of others that the parameters can be changed in the drives to give better tuning. Yes it's fiddly process with lots of parameters and the Chinglish manual doesn't help or make it simple but this is why they are so cheap.
    If folks want simplicity in tuning then buy branded name but expect to pay the same amount of money for one axis as you would 3 axis worth from China and still have spare change.!

    To the OP.
    In terms of performance then servos are no comparison to steppers in most cases. However that doesn't mean Servos are always better for the application. IMO for DIY level Mill or router then steppers are perfectly fine. Much simpler with far less hassle for not lot of money.

    I can tell you with absolute confidence because I fit both on nearly all machines I build that the AM or EM drives give excellent performance which I've yet to see beaten for the money. Reliabilty so far after fitting good few hundred has been 99.9% with only one none starter. By that mean never had one fail in use and only one which didn't work out of the box.

    The Cslabs Controllers are Top notch which ever you use and again you won't get better.

    Regards Steppers then provided you buy ones with sensible spec in terms of inductance etc then they all pretty much work the same.

    What I will say is that on Denford and Boxford router conversions I've done where all has been replaced with New steppers, AM882 drives and Cslabs controllers the performance difference is Night and Day turns the machine into different animal.

  6. #16
    No worries Jazz, i fully realise that you get what you pay for :) All it needs is a knowledgeable person to identify the Pid parameters in the manual and sort out what does what :) Trouble is they dont even call them Pid :)

    One drive not mentioned yet is the hybrid stepper-servo - a stepper with an encoder mounted and a suitable drive. I nearly fitted these on the Bridgeport but fell for servo's instead. They do sound interesting though.

  7. #17
    Hybrids are what i have and mentioned them earlier in the thread......excellent piece of kit and work brilliant.

    I have two on the y axis, one on x and a smaller one on the z....all connected with leadshine drivers and purelogic boards....

    Excellent but i did pay £2K+ for set up inc all power supplies etc...

    Tommy
    Last edited by Skiprat; 25-03-2017 at 07:44 PM.

  8. #18
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 3 Days Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,908. Received thanks 360 times, giving thanks to others 8 times.
    Andy, the main thing you have to consider, is what do you want to achieve?

    Faster rapids, faster acceleration, better positioning, just to spend some money???
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  9. #19
    Closed loop steppers are just now becoming cheap enough to be worth thinking about. I've just started fitting them to machines but In truth they offer very little more than normal stepper (open loop) when sized and tuned correctly. The smaller ones do have the advantage of using 3phase motors which give smoother action than 2 phase but other than that there isn't any advantage in power terms.
    The closed loop side isn't really anything to pay thru the nose for IMO because at best all it does is throw a fault if position is lost. Thou to be fair this is the same for servos which only close the loop between motor & drive rather than fully closing the loop back to control.

    Servos however get there advantage from the smooth linear power and speed they provide but the same holds true that if pushed too hard or tuned to high they will still lose position and the only advantage then is the fact they fault the drive. However this does come with a cost, both in money and technical knowledge required. They don't tolerate any corner cutting in control system or sloppy ness in machine. This means often the cost doesn't stop at just buying the servos.
    Standard steppers cannot do this but if sized correctly and tuned correctly they are very accurate and reliable. They don't match servos in performance but they do Match Closed loop steppers in every way. They are simple and reliable which is why they suit DIY perfectly.

  10. #20
    Quote Originally Posted by m_c View Post
    Andy, the main thing you have to consider, is what do you want to achieve?

    Faster rapids, faster acceleration, better positioning, just to spend some money???
    All Good Questions but also while at it ask your self WHY.?

    Do you really need machine that travels at light speed.? . . . . . At this size I'd say 100% not.!!
    Do you really need machine that goes from 0 to 100 in 0.01's.? . . . . . . . . . . . Probably not.!!
    Can machine handle the higher speeds.? . . . . . . . . . . . . . . . . . . . . . . . . . . Probably Not.!!
    Can the rest of machine match the positioning accuracy.? . . . . . . . . . . . . . . .Probably not.!!

    So only probable reason is because got money burning hole in pocket which is fine if your loaded.

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