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Stepper Motor Calculator .ods

Basic stepper motor calculations

  1. steelspinner

    steelspinner Well-Known
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  2. Tweakie

    Tweakie OpenBuilds Team
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    Excellent :thumbsup:

    Thank you for posting such a useful resource.

    Tweakie.



    (for those with MS Office, attached is an Excel version of Dave's calculator)
     

    Attached Files:

    #2 Tweakie, Oct 31, 2014
    Last edited: Nov 1, 2014
    Rick 2.0 likes this.
  3. Serge E.

    Serge E. Master
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    Way cool, I could of used it much earlier and get myself a more appropriate power supply, not to forget trying to figure the use of the few online calculators and such. I don't recall any of them taking into account the inductance or suggesting the ideal voltage. :thumbsup:

    The built in "mm to inches" is a nice touch as well. :thumbsup:

    The protection of fields (the formulae, people don't need to mess with them) along with the highlighting of input fields is great ;) Yes, it would be nice to know what the formulae actually are. But I trust they have been validated.

    Since I was raised with a touch of "there is always better", I'll permit myself to make a few suggestions, most being more for looks than actual function :
    • throw in a bit of of conditional formatting to avoid display of "division by zero". With some formulae magic you could show a "-" or "missing input" instead of letting the standard error text. I tend to be OCD with these aspects.
    • you could simply use default input values, such as info for OBPS steppers and such, so the beginner has a valid starting point and maybe just want to pick the right power supply to do a build.
    • which brings up : could also indicate a 'minimum' amp value for the power supply, especially if suggestion below is done. Sure, it can be an obvious calculation for many, but it just gives that little extra to your calculator.
    • have three, or at least two, near identical blocks, one for X and Y with an other for Z, or one for each : X, Y and Z ? Thus allowing the user do all three axis side by side and experiment with different steppers, mechanism and power supply before buying them. Your calculator could actually be used to tweak 'ideal' configuration to a target speed and precision. One can't expect much better than what the steppers and such being used allow for within their specs. Going beyond is ... looking over the edge of the 'planet'.
    • could even have a 'copy from' cell for each of Y and Z to have the calculator copy inputs from X in a single click since typically Y is same as X while Z could be different having a smaller/different stepper and using ACME screw instead of GT2 or GT3.
    A future versions could start looking at adding speed and feed rate calculation/factoring. It might be difficult given G-Wizard takes into account 50+ parameters to make it a 'true' science and still indicate reality could be off a bit... But "basics" would probably be great as a starting point for most of us. We might aim for perfection, but we are probably all happy/comfortable with a 'it works for me'.

    Great work. I'll cross reference the OXcalculator to this calculator for certain.
     
  4. steelspinner

    steelspinner Well-Known
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    Serge,

    Thanks for the comments. I thought about putting more into the calculator but I didn't want it to be over kill. I am also not the best at setting up spreadsheets. I only do it once in while. I would be happy to post an unlock version for whoever wants to modify it. The only formulas on it that are not basic math are the ones for motor speed using induction. I found those on the internet. (T= L*Imax*2/V, Rev/sec = V/(L*2*Imax), Pmax= 2*Imax*V/(steps/rev)) The screw force calculation is just a basic engineering formula. (Torque(raise) = F*Dm/2*(L+u*PI*DM)/(PI*Dm-u*L)) The belt force calculations just uses the calculated radius of the belt pulley with a simple ration to the torque of the motor. The force calculation are theoretical only. They don't take into account a lot of mechanical factors in each individual machine and friction is just calculated as a function of efficiency.

    I put the lock on the sheet more so that I don't click on the wrong cell and have to rework the formulas. The password is cnc for anyone who wants it.

    I am definitely not getting into a speed/feed calculator. They have been done to death and I have nothing to add in anyway. The numbers they give are just a starting point anyway. With experience you learn what works best with each machine.

    I put the calculator together to help people without a lot a design experience make informed choices about what they are going to buy and design around. I have seen on another site a lot of: "I just bought XYZ motor kit on ebay with XXXXX Chinese driver board will this work for my machine that I haven't designed yet." or "I just spent $80000000 dollars on the biggest motors I could find and am running off of this 12 volt walwort power supply I have. Why are they losing steps and going slow?" Seeing post like that make me feel bad for the frustration they people are going through and are going to go through. There are a lot of really decent (as far as you can tell on the interwebs) people who post on here. Everyone seems to really want to learn and do the best with what they have. I am just glad I can help, atleast a little. :thumbsup:

    Dave
     
  5. Serge E.

    Serge E. Master
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    Indeed yours would be perfect for those, like me, who kind of blindly bought steppers and power supply. Well, I sort of had an idea, but certainly did not pick the ideal power supply (voltage is low at 12 volts !)

    No problem for the rought edges, it works and is useful as is.

    By the way, the cells are locked but there was no password in the copy I downloaded earlier.

    I have to tweak the OXcalculator a bit more, but, if you want, I could spend a bit of time making some of my suggestions into what you have done so far. If you are ok with it, I could do an hybrid of both calculators at some point. With the proper attribution, of course. It be a nice marriage of the two... By then, I'll probably protect the cells people should not mess with, but have no password for those who want to tinker some more.
     
  6. steelspinner

    steelspinner Well-Known
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    I for sure have no problem with it Serge. Any way to get the info to people who can use it is great in my opinion. :thumbsup: If there is any other info you would like to include and don't have, let me know and I will see what I can come up with. The only thing I ask is that you lock the formula cells when your done so that we don't get a million and one "it doesn't work" posts because someone messed up a formula by accident.
     
  7. Serge E.

    Serge E. Master
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    Perfect. I'll be looking at it this weekend. Right now I think I have the squaring issue with myOX licked :rolleyes: So I want to confirm before moving ahead with everything else even closely related.
     
  8. steelspinner

    steelspinner Well-Known
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    Serge,

    I know a couple of ways to check squareness pretty accurately. Let me know if I can help.

    Dave
     
  9. Serge E.

    Serge E. Master
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    I believe I have it under control now, but I am all ears (eyes) if you want to share your trick. Maybe I can make double sure myOX is as square as it can be (in my hands). Others might find it of value as well.

    Quick measurements and I think I'm down to about 1 mm off, end to end of the 1500 mm length. I'll know better when the weekend comes with tests and careful measurements.
     

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