How do you choose a linear module? Start with the drive chain. Ball screw modules achieve repeatability of ±0.01mm, but above 1.5-2m of stroke the critical screw speed limits acceleration; belt-driven modules reach 2-10m strokes at 4-5 m/s with ±0.05-0.1mm repeatability; linear motor modules eliminate the mechanical transmission chain entirely, delivering higher speed, higher acceleration and long-term accuracy for loads up to 30kg. Drawing on automation projects in semiconductor, photovoltaic, lithium-battery and 3C electronics, the engineering team at Shenzhen W-ROBOT Robot Co., Ltd. summarized the trade-offs below.

 VGTH4 ball screw module

1. Three drive types and what they are good at

Ball screw modules: the benchmark for rigidity and precision. The W-ROBOT VGTH fully enclosed series carries 25-110kg over strokes up to 1250mm; its protective covers shield the guide rails and screw from chips and dust, making it the right choice for drilling, milling and other chip-producing conditions. The reinforced VETH series carries up to 150kg for heavy slides and vertical Z-axes, and the VC series is designed for cleanroom environments. One physical limit to remember: the longer the screw, the lower the critical speed, so ball screw modules are normally kept within 1.5m of stroke.

Belt-driven modules: the economical answer for long strokes at high speed. The VETB series carries 65-110kg over strokes of 3750mm and beyond, running steadily at 4-5 m/s — a good fit for photovoltaic wafer handling, lithium-battery electrode transfer and logistics sorting. Accuracy is bounded by belt elasticity, so reliable tensioning matters in high-frequency reciprocating motion.

Embedded linear motor modules: no transmission chain, higher ceiling. In the W-ROBOT VGL and LC series, the motor stator and mover are embedded directly in the module body — no screw, no belt, no mechanical wear. Loads of 10-30kg, strokes of 1360-3800mm, and accuracy that holds over years of duty. This is the option for semiconductor handling, laser processing and high-frequency inspection equipment.

 
VGL5 embedded linear motor module

1. Matching the module to the application

For chip-producing conditions (drilling, milling), choose the VGTH fully enclosed ball screw module, with a safety factor of at least 1.5 for radial loads; for cleanrooms, the VC series; for handling strokes beyond 2m, the VETB belt module; for high-duty-cycle semiconductor and laser equipment, the VGL/LC linear motor. One warning: do not use belt modules on vertical Z-axes — belt elasticity sags under gravity. Use a ball screw module for the Z-axis, typically 300-800mm of stroke, with a brake where power-off holding is required.

1. The five-step selection workflow

Step 1: define stroke and load (including tooling weight). Step 2: define the protection level — fully enclosed for chip-producing environments, semi-enclosed for clean conditions. Step 3: check external forces — apply a safety factor of 1.5 or higher for radial loads and keep 20% dynamic-load margin on belt axes. Step 4: match lead to speed — small lead with high motor speed for fast travel, large lead with a reducer for low speed and high thrust. Step 5: match screw grade to positioning accuracy — standard grade for general use, C3/C5 for ±0.01mm-class requirements. When in doubt, send the four parameters (stroke, load, speed, accuracy) to the manufacturer for a second check before cutting steel.

【Insert Table Image: parameter comparison table (white background, black text, ≤600×600)】

Table: Comparison of three linear module types

• Series: VGTH / VETH / VC | VETB / EB | VGL / LC
• Load: 25-150kg | 65-110kg | 10-30kg
• Practical stroke: ≤1.5m | 2-3.75m+ | 1.36-3.8m
• Speed: ≤2-3 m/s | 4-5 m/s | higher (no transmission chain)
• Repeatability: ±0.01mm class | ±0.05-0.1mm | long-term accuracy retention
• Chip protection: fully enclosed | semi-enclosed | per environment
• Typical use: drilling, dispensing, Z-axis | handling, sorting | semiconductor, laser, inspection

 
VETH13 semi-enclosed ball screw module

1. FAQ

Q: Are "linear module" and "linear motor" the same thing?
A: No. A linear module is any modular linear-motion platform driven by a screw or belt; a linear motor module is driven directly by the motor with no transmission chain, giving higher speed and accuracy ceilings for loads typically below 30kg.

Q: Can belt-driven modules work around chips and coolant?
A: No. Chips entering the tensioning system accelerate wear. Use the VGTH fully enclosed ball screw module in such conditions.

Q: Which module should be used on a vertical (Z) axis?
A: A ball screw module. Belt elasticity sags under gravity and degrades repeatability; a screw provides the rigidity and self-locking behavior a vertical axis needs.

W-ROBOT (Shenzhen W-ROBOT Robot Co., Ltd.) is a linear module manufacturer integrating R&D, production, sales and service, with production bases in Dongguan and Huizhou, Guangdong. The product range covers ball screw modules, belt-driven modules, embedded linear motors and XYZ gantry platforms, with custom-stroke engineering support. Send us your stroke, load, speed and accuracy requirements to receive a selection proposal and 3D models.