1. #1
    Hi all, Can anyone tell me how much force could be applied to the top of a material using a Nema 23 and a 1605 ballscrew, I realise this would be dependant on the weight of the Z assembly, so lets say that weighed 5lbs. im sure there will be other information required so ask away.

    Rick
    Always bear in mind that your own resolution to succeed is more important than any other - Abe Lincoln

  2. #2
    Not quite sure what you're asking - do you want to know how much force the motor can apply if the Z-axis pushes straight down into the material?

    If so, then the answer is dependent primarily on what speed the motor is running at and clearly what motor/driver you are using. For sake of argument lets say it's a 3Nm motor on 70V, operating below the corner speed (about 880rpm = 4400mm/min), which is realistic as the Z-axis rarely goes very fast. Under those conditions the torque is a 2Nm.

    Formula for driving force, F=T*2*pi*e/L where T is torque, L is pitch (m/rev) and e is efficiency (around 90% for ballscrew).

    So with 2Nm on a 5mm pitch ballscrew, remembering that lead is in meters, you have; F=2*2*pi*0.9/0.005=2262N

    We should factor in the weight of the Z-axis, but as you can see ballscrews/leadscrews can apply a huge amount of force so this is negligible in comparison. So in short don't stick your fingers under it!

    Does that answer your question?
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  3. #3
    Quote Originally Posted by Jonathan View Post
    Not quite sure what you're asking - do you want to know how much force the motor can apply if the Z-axis pushes straight down into the material?

    If so, then the answer is dependent primarily on what speed the motor is running at and clearly what motor/driver you are using. For sake of argument lets say it's a 3Nm motor on 70V, operating below the corner speed (about 880rpm = 4400mm/min), which is realistic as the Z-axis rarely goes very fast. Under those conditions the torque is a 2Nm.

    Formula for driving force, F=T*2*pi*e/L where T is torque, L is pitch (m/rev) and e is efficiency (around 90% for ballscrew).

    So with 2Nm on a 5mm pitch ballscrew, remembering that lead is in meters, you have; F=2*2*pi*0.9/0.005=2262N

    We should factor in the weight of the Z-axis, but as you can see ballscrews/leadscrews can apply a huge amount of force so this is negligible in comparison. So in short don't stick your fingers under it!

    Does that answer your question?
    Over the weekend i will be loading my gantry (in lbs) in the middle to measure the deflection and too see if it needs more work, so i needed a guide weight to go by. my 3nm nema23 on 70v (good guess there) may be replaced with a nema 34 but ive not decided which one yet.
    Always bear in mind that your own resolution to succeed is more important than any other - Abe Lincoln

  4. #4
    Quote Originally Posted by Ricardoco View Post
    Over the weekend i will be loading my gantry (in lbs) in the middle to measure the deflection and too see if it needs more work, so i needed a guide weight to go by.
    I'd be wary of using the Z-axis to do that as unless you have something to measure the force, such as putting bathroom scales underneath the Z-axis, you could seriously damage something - 2262N is 508lb.f.

    Quote Originally Posted by Ricardoco View Post
    my 3nm nema23 on 70v (good guess there) may be replaced with a nema 34 but ive not decided which one yet.
    How much does your Z-axis weigh, just the bit that moves up and down so we can work out the motor and driver? It'll be quite a lot with the spindle and motor you're planning on, but generally such high speed isn't required on the Z-axis anyway.
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  5. #5
    Quote Originally Posted by Jonathan View Post
    I'd be wary of using the Z-axis to do that as unless you have something to measure the force, such as putting bathroom scales underneath the Z-axis, you could seriously damage something - 2262N is 508lb.f..
    LOL thankyou for the warning but im not that heath... I have a motorcycle scissor lift with digital weight guage on it and that can go beyond 1.5 tone, so we should be ok there and i will be building my Z when i know what forces i will require it to achieve.



    Quote Originally Posted by Jonathan View Post
    How much does your Z-axis weigh, just the bit that moves up and down so we can work out the motor and driver? It'll be quite a lot with the spindle and motor you're planning on, but generally such high speed isn't required on the Z-axis anyway.
    Ahhh now there is a question..lol, I will not be able to answer that until i have my Spindle and Motor. So for now i am working on reducing any twist or flex on the gantry itself.
    Always bear in mind that your own resolution to succeed is more important than any other - Abe Lincoln

  6. #6
    Quote Originally Posted by Ricardoco View Post
    LOL thankyou for the warning but im not that heath... I have a motorcycle scissor lift with digital weight guage on it and that can go beyond 1.5 tone, so we should be ok there and i will be building my Z when i know what forces i will require it to achieve.



    Ahhh now there is a question..lol, I will not be able to answer that until i have my Spindle and Motor. So for now i am working on reducing any twist or flex on the gantry itself.
    I am also considering belt drive 2:1 gearing so it wont be fast anyhow, but i need to test the gantry Re-inforce if need be test again and work out what stepper and driver i require so neither the stepper or the gantry is stressed beyond its capability.
    Always bear in mind that your own resolution to succeed is more important than any other - Abe Lincoln

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