SFE Ball Screw

The SFE ball screw is a high-lead ball screw series with an internally recirculating flanged single nut. Its main characteristic is the large linear travel produced by each revolution of the screw shaft.

DLY SFE models cover screw diameters from 16 mm to 50 mm and leads from 16 mm to 64 mm. Standard combinations include 16×16, 16×32, 20×20, 20×40, 25×25, 25×50, 32×32, 32×64, 40×40 and 50×50 mm.

SFE High-Lead Design

Ball screw lead is the distance travelled by the nut during one complete revolution of the screw. For example, an SFE1616 moves 16 mm per revolution, while an SFE3264 moves 64 mm per revolution.

At the same rotational speed, a larger lead produces a higher theoretical linear speed:

Large lead also changes the required driving torque, positioning resolution and resistance to back-driving. Motor capacity, axial load, screw speed, support arrangement and braking requirements should therefore be checked together rather than selecting the screw by travel speed alone.

SFE Model Examples

SFE1616
16 mm diameter and 16 mm lead

SFE2525
25 mm diameter and 25 mm lead

SFE3232
32 mm diameter and 32 mm lead

SFE Ball Screw Dimensions

The SFE nut uses a flanged single-nut structure with an internal ball return path. Dimensions D, A, E, B, L, X, W and H correspond to the drawing above. All standard models in the table use an M6 lubrication port.

Dimensions are in millimetres. Ca and Coa are stated in kgf; stiffness K is stated in kgf/μm. The -3 and -6 suffixes identify different ball-circuit configurations and must be included when confirming a model.

Selecting Between -3 and -6 Configurations

Each standard diameter-and-lead combination is listed with two circuit configurations. The -6 version provides higher dynamic load, static load and stiffness ratings than the corresponding -3 version.

The higher rating does not mean that the -6 version is automatically required. Selection should be based on the actual axial load, duty cycle, required service life, acceleration and available nut installation space.

Typical SFE Applications

SFE is primarily selected for fast-feed axes, transfer mechanisms and automation systems where a large linear distance is required from each screw revolution. The following images show representative equipment categories in which an SFE model may be evaluated.

CNC Machine Tools
Fast-feed and positioning axes where the selected load and speed remain within the screw ratings.

Factory Automation
Transfer, feeding and repeated positioning mechanisms requiring rapid linear travel.

Robotics and Handling
Linear movement units in automated handling and robotic support mechanisms.

Semiconductor and Inspection Equipment
Motion mechanisms where the required lead, accuracy, load and environment have been individually verified.

Medical Equipment Mechanisms
SFE may be evaluated for non-sterile mechanical motion units after application requirements are confirmed.

Measuring Equipment
Rapid positioning mechanisms where the selected accuracy grade meets the measurement system requirements.

Accuracy and Materials

• Standard accuracy: C7 rolled ball screw.
• Optional accuracy: C5 ground ball screw, subject to model confirmation.
• Screw shaft material: S55C.
• Ball nut material: 20CrMo.
• Nut structure: Internally recirculating flanged single nut.
• Thread direction: Right-hand thread is standard.

SFE Model Confirmation

Confirm the complete model suffix, total screw length, accuracy grade, shaft-end drawing and operating conditions. For high-lead applications, critical speed, axial load, support arrangement, motor torque and possible back-driving should be checked before final selection.

For conventional 4 mm, 5 mm or 10 mm lead combinations, compare the SFU ball screw.