Calculate Ball Screw

We could spend hours going into this - the formulae are pretty simple, but there are many variables.

Easiest thing is to contact ball screw suppliers, who will trip over themselves telling you exactly what you need. If you contact 2 or 3, you can play them off against each other to get a good price.

Motor & drive suppliers are worth asking, as well, if you haven't already sourced that side of your system.

If you're starting from scratch, it's worth getting ball screw, motor & drive from one supplier. This eliminates the possibility of each supplier blaming the other if the system doesn't work, and, since they recommended it, they'll have to get it working.

To a large part it depends on how fast you want to accelerate/decelerate the load and if the ball screw is contributing anything other than just acceleration forces such as load support. Also screw diameter is sometimes governed by travel distance and travel rate so the the ball screw doesn't "whip". Most ball screw manufacturers have a section in their catalogue that steps you thru the process.

If you are asking about the theoretical maximum torque of a certain ball screw configuration, its a simple inclined plane lifting problem with rotation torque (moment) thrown in.

Dear Guest,

There are so many things to consider while selecting lead screw.

Apart from what has already been mentioned, the following will also play a role.

1. The friction existing on the horizontal slide.

2. Type of drive (Motor etc.)

3. Precision of movement.

and ofcourse the acceleration & decelaration.

Regards,

__For Knowledge purpose___

Load a ball screw can carry is usually determned by the female part ( i.e.re-circulating ball nut...made of phosphor based bronze).

Multiply the no:of threads on female ( including the ones with multi-start), the mean diameter of the screw size, pitch (not lead pitch) and the shear strength of the material (phosphor bronze ) to get the load bearing capacity. For screw in particular, calculate for buckling force and rest other parameters will fall in place by default, irrespective of the size......and not to mention the screw is made of steel (varities available ) and is strong enough as any other male part, if buckling is taken in to consideration :-)

Mr.Idiotalways