Every Bridgeport mill rebuild has the option to upgrade to a Precision Ball Screw kit, but only 1 in 6 will purchase the upgrade, according to Bridgeport Machine Rebuilders. The initial cost will typically scare off a Purchasing Agent, Maintenance Manager, or Machine Shop Supervisor. But if those ball screws will last longer and be much more accurate over the life of "multiple" acme screws, does it make sense to add this option to your Bridgeport mill rebuild?
Let’s dig a little deeper into this and see if a precision ball screw upgrade makes sense.
What is a Ball Screw?
A ball bearing screw is just that: a screw which runs on ball bearings. The screw and nut have matching helical grooves or races, and the ball bearings recirculate in these races. There is physical contact between the screw and the nut. As the screw or nut rotates, and the rolling balls reach the trailing end of the nut, they are deflected or guided from this “pitch” contact by means of a return tube and returned to the leading end of the circuit. There, the cycle resumes and the balls recirculate continuously.
So in layman’s terms: a ball screw has ball bearings that provide a smooth and easy rotation and/or movement, while basically limiting or removing friction that causes wear on the screw. Or something like that.
Let’s focus on the Benefits:
Limited Wear – Because of the rolling contact, wear is far less than that of sliding contact. The end result, deterioration of accuracy is extremely low over the life of the ball screw.
Less Force – Since friction loss is extremely low, the amount of force used to rotate the screw shaft is as low as 1/3 of that needed for the acme thread lead screw.
In a nutshell: Your ball screw will have limited wear over the life of the ball screw and will maintain a high level of accuracy.
The formula below proves this... we think?
So if your application calls for higher accuracy and you want to limit maintenance/downtime costs in the future (when your acme screws need to be replaced), then ball screws may just be the ticket for your Bridgeport mill.
Let’s dig a little deeper into this and see if a precision ball screw upgrade makes sense.
What is a Ball Screw?
A ball bearing screw is just that: a screw which runs on ball bearings. The screw and nut have matching helical grooves or races, and the ball bearings recirculate in these races. There is physical contact between the screw and the nut. As the screw or nut rotates, and the rolling balls reach the trailing end of the nut, they are deflected or guided from this “pitch” contact by means of a return tube and returned to the leading end of the circuit. There, the cycle resumes and the balls recirculate continuously.
So in layman’s terms: a ball screw has ball bearings that provide a smooth and easy rotation and/or movement, while basically limiting or removing friction that causes wear on the screw. Or something like that.
Let’s focus on the Benefits:
Limited Wear – Because of the rolling contact, wear is far less than that of sliding contact. The end result, deterioration of accuracy is extremely low over the life of the ball screw.
Less Force – Since friction loss is extremely low, the amount of force used to rotate the screw shaft is as low as 1/3 of that needed for the acme thread lead screw.
In a nutshell: Your ball screw will have limited wear over the life of the ball screw and will maintain a high level of accuracy.
The formula below proves this... we think?
So if your application calls for higher accuracy and you want to limit maintenance/downtime costs in the future (when your acme screws need to be replaced), then ball screws may just be the ticket for your Bridgeport mill.
Ball Screw Kit for Bridgeport mills
Ball Screw - How it works
Ball Screw - Reduced Friction
Ball Screw Life Expectancy