Select electronics for my raptorxz - Page 2


Page 2 of 5 FirstFirst 12345 LastLast
Results 13 to 24 of 53

Thread: Select electronics for my raptorxz

  1. #13
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    Ok My findings so far:

    For 3d Printing it is an advantage it the setup is max 36V (not getting into detail here...) so i have been looking for a combination which gives good speed and torque On my 36x48 machine and still enables it to in a simple way (both useabillity and design wise) ti do some 3d Printing.

    Not to forget, The machine must perform well cutting Aluminium!

    So i found a 4 axis kit giving me best of all worlds. Again using the calc in first post i get the following:

    stepper is 1.6mH/phase (6wire) --> 32*sqrt(1.6) = 40.5volt optimal power
    stepper is 3.0A/phase --> 21.1 rev/sec @ 40.5 volt
    leadscrew is 10mm --> 211mm/sec --> 8.3inch/sec --> 498IPM

    now powersupply is 36v for reason above:
    stepper is 3.0A/phase and 1.6mH Ind. --> 18.8 rev/sec @36v
    leadscrew is 10mm --> 188mm/sec --> 7.4inch/sec --> 444IPM

    What I still do not understand is consequenses/effects of having a 6 wire stepper and the different ways i can connect it.
    Anyone?




  2. #14
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    found the answer...
    --> UniPolar vs BiPolar wiring schemes for 2-phase Stepper Motors

    Each phase is 3 wires, beginning, middle, end.

    Following this guide you connect beginning and end as wire1 and center as 2 and same for next phase as 3 and 4 and for the rest follow the setup as if it was a 4 wire motor.

    For future reference if link above goes dead, the wireing above is called "Bipolar Halfcoil" and does not affect specifications of motor (as if it were a 4 wire).



  3. #15
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    The more i learn the more i fall to the understanding i know now nothing....... -

    Im trying to find a stepper to go with my 10mm ballscrew. it will move the gantry (est. 15Kg). I needs lots of acceleration. I want it to reach 350+IPM speed within 3 inches or so. It needs only torque enough to handle the weight of the gantry at these speeds (3dPrinting) but at the samt time have torque enough to do aluminium routing at lower feed. I have been calculating for days now using online calculators etc. but everytime i find something new i get setback with new info.

    Any suggestions?



  4. #16
    Member BanduraMaker's Avatar
    Join Date
    Dec 2010
    Location
    USA
    Posts
    623
    Downloads
    0
    Uploads
    0

    Default

    You have conflicting requirements. G540 at 48v with the motors I recommended should exceed the speed/accel requirements you've stated. Dropping the supply voltage to 36v will hamstring your drive system.

    Since you've bought a Raptor, I have to think that 3D printing is less of a priority than milling as there's no reason to go with something this rigid for 3D printing. So, decide what's important to you and the solution will become more clear.

    -Andy B.
    http://www.birkonium.com CNC for Luthiers and Industry http://banduramaker.blogspot.com


  5. #17
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    Yes - BanduraMaker - I am slowly realizing that. lol ...and Yes Milling is a priority but having a print speed less than 150mm/s will force me into having two machines where one always is standing still. This is the reason I am willing to spend a lot on one machine, and also two machines will not fit in the area designated for the task.

    After another 3 hrs of reading during the day my conclusion is that the size / weight of the machine will require about 50v or more when using NEMA 23 steppers. The printer solution will have to be some custom built controller board using external voltage supply and the drivers incorporated into the board.

    So I dropped the 36v target and now I will try to find a 50v system to keep the driver price down. G-540 looks promising but so does DQ542MA. The Gecko G-540 has spindle outputs but that should not matter since i will use a smoothstepper Ethernet and can break out the nessesary outputs from there.



  6. #18
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    I believe that the setup from suggested by BanduraMaker is up for the task if he says so, but I cannot get my head around the math. Using the known formulas these motors should Max out at 12.2RPS = 732RPM and with 10mm Lead This translates to 288IPM @48v cranking up the voltage to 53v would result in 312IPM.
    To meet requirements i need at least 355IPM = 150mm/s. BanduraMaker says the combo does 400IPM on his with 10mm lead, so what am i doing wrong?



  7. #19
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    AAAARGH! Just sead into a thread on DSP Drivers.... Another all new world *sigh* More reading... Just realizing - by the time i have all the info on what i need i´ll be able to write a book on the subject. - Still cant make out the math.....



  8. #20
    Member BanduraMaker's Avatar
    Join Date
    Dec 2010
    Location
    USA
    Posts
    623
    Downloads
    0
    Uploads
    0

    Default

    Several days ago I ran my numbers through that calculator and came up with the same 288ipm (or something close to it) but I can tell you for sure that my big axis is running at 400ipm with an accel of 30. The smaller axes are at 450ipm with accel around 50.

    I can only guess that the calculator is a very conservative estimate. Don't forget that units like the G540 have micro stepping and other tricks up their sleeves to work the motors harder.

    With the larger size of your machine, it probably won't get quite to the performance of mine (I've got the 24x36) but you should be able to come pretty close.

    -Andy B.
    http://www.birkonium.com CNC for Luthiers and Industry http://banduramaker.blogspot.com


  9. #21
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    BanduraMaker: It would be nice to see a volt and amp reading from your motors to see if the gecko does some magic!



  10. #22
    Member BanduraMaker's Avatar
    Join Date
    Dec 2010
    Location
    USA
    Posts
    623
    Downloads
    0
    Uploads
    0

    Default

    No need, the magic are a few things that's on their website. have no idea how much each influences the performance but they claim that their drives use microsteping, midband resonance damping and "morphing" to get better performance out of the motors and what can I say? It works.

    You can ask anyone on this website that has used more basic drivers that resonance can be a serious problem with stepper stalling at mid to low RPM. Adding dampers to the shaft of the motors can fix it and apparently there's DSP tricks one can do to get rid of it too.

    You may have heard people say before that "according to physics, bumble bees can't fly"? Well, that's absolutely not true. According to physics bumble bees absolutely can fly it's just that elementary physical models don't accurately reflect what's going on to get the damn thing to fly. When the model gets more sophisticated, it more accurately shows how the bee is flying.

    Seeing as my machine runs at 400ipm on the big axis, and I regularly cut at 400ipm, I'm going to say "my bumble bee flies". If the calculator on that site doesn't match my performance it's down to a couple things - either we're entering the parameters incorrectly or the calculator is just plain wrong. I guess to be more kind one could say as I mentioned before, that the calculator is conservative rather than just plain wrong.

    Gecko Drives may not be the best stuff out there but there's a reason they have a good reputation and are recommended on this site. While it's not the solution for every machine, the G540 gives you great performance bang for your buck when it fits the bill.

    -Andy B.
    http://www.birkonium.com CNC for Luthiers and Industry http://banduramaker.blogspot.com


  11. #23
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    Ok.. i found a comment which might explain it... Digital drives can swith between coil states quicker because amps need not to be constant, because of this higher speed is achievable when full torque is not needed also optimized by stall detection.

    These facts have made me consider the Leadshine EM705 combined with 57hs22 LeadShine steppers. This leaves room for a nema 34 upgrade eventually (if i need better acceleration during 3d printing).

    Sent from my GT-I9505 using Tapatalk

    Still Learning..... :D


  12. #24
    Registered
    Join Date
    Nov 2013
    Posts
    92
    Downloads
    0
    Uploads
    0

    Default

    microsteping, midband resonance damping and "morphing" should all be factors limiting the steppers performance from calculated max. Calculator is based on the time it takes to fully charge and then discharge the coil to produce one step. Max voltage in 32xsqrt(Inductance) is only the voltage at which a stepper will produce lots of heat in the motor with very little performance gain. Depending on the torque curve it is quite easy to see that adding voltage above this value is just plain stupid. Exceeding it is not a catastrophe in small ammounts but every volt above is more or less translated into heat. Having a result of 48v from the formula says it will be ok to power at 50v but the additional volts will do little or no gain in performance, 60v vould be really bad as biggest part would be translated into heat (for example 6Amp motor would lead to between 8 and 12v multiplied with 6A equals 48 to 72 Watts of heating.

    The only thing i can see that might affect speed beyond theoretical values is not fully loading the coil to faster be able to switch state. Now this math is beyond me..



Page 2 of 5 FirstFirst 12345 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Select electronics for my raptorxz

Select electronics for my raptorxz

Select electronics for my raptorxz