Ballscrews and FA Series


Our production of the PMI ball screws has adopted a manufacturing 

process and equipment unlike other manufacturers. Combining advanced skills and the Bad Düben digital electric screw thread rolling machine, we adhere to a strict quality control policy at every stage of production, from the selection of ball screw material and rolled processing to the induction hardening heat treatment and post production. We are committed to providing clients with products of the best quality.


The combination of rolled ball screws and ground nuts has replaced the traditional ACME screws and trapezoidal screws. This makes for a smoother operation while reducing friction and backlash. Moreover, the new technology has the advantage of faster production speed and lower prices.


Besides the differences in the definition of lead deviation and geometric tolerance, rolled and ground ball screws can both eliminate axial play by preloading.

  • Precision Ground Type

  • Rolled Type

  • FA Series

The advantage of internal ball circulation nut is that the outer diameter is smaller than that of the external ball circulation nut. Hence it is suitable for machines with limited space for ball screw installation.

It is strictly required that there is at least one end of screw shaft with complete threads. Also the rest area next to this complete thread must be with smaller diameter than the nominal diameter of the screw shaft.

Above are required for easy assembling the ball nut onto the screw shaft.

The end deflector series ball screw type, circulation system use high rigidity and against material of strong plastic. The specially designed pathway of the circulation system makes a contact with lead angle and also with ball circle diameter (BCD) in the same tangency, improving its smoothness effectively.

The ballnut diameter reduces 20%~25% substantially and the length of nut is shorter. Application in high-rigidity、lower-noise and high-lead.

 The conventional type of ball nut of the external circulation ball screws, using return tube circulation system.


Offers better solution and quality for general lead or large diameter ball screws.

The specially designed pathway makes a ball circle diameter (BCD) into the return tube by tangency direction to match the direction of lead angle.


Offers smooth ball circulation to improve lifetime and reduce noise level.

 Focused on improvement of contact points of balls and thread grooves,ball diameter and circulation system for new type.


The rated dynamic load has been increased to as two times as that of conventional type, FSVC

End cap series use the through hold which crosses both end of nut to consist a close loop. End cap and wiper are one-piece make the shortest length of nut.


Application in high-lead and multiple thread grooves of ball screws.

External circulation system, it don't need to have at least once end with complete thread to the end of ballscrew for ballnut assemble to screw shaft.

The special design of ballnut, so the size of ballnut is the same as internal circulation system of ballnut, Space saving. Hence it is suitable for the φ6~φ16 of shaft diameter  and under φ2 of ball diameter of ball screws.