Need help with my calculation to find the stepper the motor that allows for the use right pulley

Hi, I need help finding the right stepper motor for an X and Y gantry.

The formula I was given to solve the right torque is Force and Torque.

F=mgu

M=mass

G=gravity

U=coeffiction of friction

Torque

T=f*d

T=torque

F=force

D=radius of pulley

1)x-axis distance range is about 2ft 5in.

F=(7kg)(9.81m/s)(0.5)=34N

T=(34N)(4mm)=136mNm

  1. y-axis distance range is about 1ft 6in.

F=(4kg)(9.81m/s)(0.5)=20N

T=(20N)(4mm)=80mNm

*These are the stepper motor I found for x and y.

1)x-axis NEMA 17 39oz-in. torque

2)y-axis NEMA 14 20oz-in. torque

  1. x-axis timing belt(9mm width, 745mm pitch length, 149 tooth).

  2. y-axis timing belt(9mm width, 650mm pitch length, 130tooth).

*can someone help me with this? Or show an example of how?

*need help to find the right pulley shaft to the match stepper motor. the pulley is 8mm, but most of the stepper motors are 5mm shafts.

A short length of 8mm rod pressed into the pulley hub and then drilled with a 5mm drill should fix it.

Look for "shaft couplers". Servocity, Mcmaster Carr, etc. have them.

Keep in mind that there are often severe restrictions on the amount of weight you can hang from a motor shaft. It is in the motor specifications, the term might be radial load.

Would You mind posting a picture or a drawn sketch showing what You're talking about?

Decide for a stepper producing the needed torque. There's no use for a stepper that fits the pulley but has too little torque....

yes

I have deleted your other cross-post @th504.

Cross-posting is against the rules of the forum. The reason is that duplicate posts can waste the time of the people trying to help. Someone might spend 15 minutes (or more) writing a detailed answer on this topic, without knowing that someone else already did the same in the other topic.

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In the future, please take some time to pick the forum category that best suits the subject of your question and then only post once to that forum board. This is basic forum etiquette, as explained in the "How to get the best out of this forum" guide you will find at the top of every forum category. It contains a lot of other useful information. Please read it.

Thanks in advance for your cooperation.

Screen Shot 2022-03-05 at 1.23.20 PM

Screen Shot 2022-03-05 at 1.23.33 PM

Can you see it?

No motor but the rigg. Fine.

NEMA 14 tells about the outer physics of the motor but tells nothing about torque, current etc.
Search the internet for timing belts and pulleys. There's plenty out there. If You have the courage to buy from Ebay, they have pullies.

NOWHERE in your calculation to you account for using a lead screw for movement. If it is of reasonably good quality, the TORQUE required to turn the screw will be so close to zero that ANY stepper motor can turn it.


this is what I got for x axis.


this is for the y axis


this is the belt I got for x axis.
Can it be any kind a pulley?

we are not using lead screw. its like pulley system moving horizontal x and y gantry

I got it. Thanks for the documentation.
You can always trade speed versus power. Small pulleys gives more power but move more slowly. Larger pullies moves faster but has less force.

Those steppers are not very powerful running at 0.6 resp. 0.8 Amps.

What is that platform supposed to carry? You have not told the whole story yet. Is it a mini mill, a plotter or what?
Heavy objects have a larger inertia.

Then did you account for the resistance of the slides to movement? The only linear rails I have encountered have ball bearings in the slides.

The steppers on my Anet A8 3D printer all have a 5mm output shaft and the 'Lead Screws' are 8mm, a gear with 5mm hole half way through and 8mm from the other end. On the numerous occaisions I have had to replace the rods, bearings & lead screws even the cheapest chinese traders have offered a choice of 5mm, 8mm or 'half n half'