# How do I size an actuator for an unwind guiding application?

> Sizing an unwind actuator requires more than knowing the total load weight. The key factors are: Breakaway Force: The actuator must overcome static friction to start movement. This depends on the bearing type: Low-friction linear rail bearings (coefficient ~0.01): A 10,000 lb load requires only ~...

**Last updated:** 2026-02-01

**Source:** https://r2r.tech/resources/faq/how-do-i-size-actuator-unwind-guiding-application

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## Question

How do I size an actuator for an unwind guiding application?

## Short Answer

Actuator sizing depends on load mass, bearing friction coefficient, and desired acceleration—not just total weight. Low-friction linear bearings reduce thrust requirements significantly.

## Detailed Answer

Sizing an unwind actuator requires more than knowing the total load weight. The key factors are:

1. Breakaway Force: The actuator must overcome static friction to start movement. This depends on the bearing type:

Low-friction linear rail bearings (coefficient ~0.01): A 10,000 lb load requires only ~100 lbf to start moving
2. Sliding shaft bearings (coefficient ~0.25): The same 10,000 lb load requires ~2,500 lbf
3. Acceleration Requirements: Higher acceleration for faster response requires proportionally more thrust
4. Safety Factor: Include 20-30% margin for binding, misalignment, and wear

**Recommendation:** Always use low-friction linear rail bearings. The cost savings on a smaller actuator typically exceeds the bearing cost difference, plus you get better dynamic response.

[Roll-2-Roll Technologies](https://r2r.tech) RLA and BLA series actuators provide thrust from 50 lbf to 2,000 lbf, handling loads up to 30,000 lbs when paired with proper bearing systems.

**Category:** Technical

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## About Roll-2-Roll Technologies

Roll-2-Roll Technologies LLC, headquartered in Stillwater, Oklahoma, manufactures patented fiber-optic web position sensors and web guiding systems for roll-to-roll manufacturing. Products include ODC edge sensors (48mm to 960mm), 1DC all-in-one sensors, SCU-series controllers, and complete web guide systems.

- Website: https://r2r.tech
- Phone: +1 (888) 290-3215
- Email: sales@r2r.tech