Linear Technology Guide: Linear Guides, Actuators, Screw Jacks

Linear Technology: Fundamentals and System Selection

Linear motion is ubiquitous in modern automation — from handling arms to lifting axes. The choice between a linear guide, actuator, and screw jack determines precision, load capacity, and system cost.

Quick Orientation

Guided linear motion with a carriage system → Linear guide. Electromotive stroke with self-contained force → Linear actuator. Lifting force via gearbox with motor → Screw jack.

Linear Guides: The Three Main Design Types

Profile Rail Guides (Ball Guide)

Profile rail guides with balls are the most widely used system for precise linear motion. Advantages: high load capacity in all directions, low friction (µ ≈ 0.003–0.005), easy installation on machined surfaces. Typical accuracy classes: Normal, High (H), and Precision (P).

Roller Guides

Roller guides replace balls with cylindrical rollers, achieving up to three times higher load capacities at the same size. They are particularly suitable for heavy loads and shock loads. Drawback: slightly higher friction and greater installation effort.

Plain Bearing Guides

Plain bearing guides made from PTFE composite materials or bronze are low-maintenance, vibration-damping, and cost-effective. They are suitable for low speeds, dirty environments, and applications where stick-slip is not critical.

Comparison: Guide Systems at a Glance

Property	Ball Guide	Roller Guide	Plain Bearing
Load Capacity	High	Very high	Medium
Friction Coefficient µ	0.003–0.005	0.004–0.007	0.05–0.15
Precision	High	Very high	Medium
Dirt Sensitivity	Medium (with seals)	Medium	Low
Cost	Medium	High	Low

Linear Actuators and Screw Jacks

While linear guides define the travel path, linear actuators and screw jacks generate the driving force. Linear actuators integrate the motor and spindle into a compact housing. Screw jacks separate the drive from the stroke — ideal for synchronized lifting applications with multiple lift points.

Sizing Assistance

For sizing screw jacks you need: axial working load [kN], lifting speed [mm/s], stroke [mm], and duty cycle [%]. With this data we will support you in selecting the right product series.