# 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:** 2026-10-06

**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 BLA and RLA series actuators provide nominal thrust from 150 lbf to 2,000 lbf. The BLA-067 moves about 10,833 lb on rolling bearings at μ 0.06 (6,500 lb at μ 0.1); the RLA-200 moves about 33,333 lb at μ 0.06 (20,000 lb at μ 0.1). See the [BLA](https://r2r.tech/products/actuators/bla) and [RLA](https://r2r.tech/products/actuators/rla) load tables.

**Category:** Technical

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## About Roll-2-Roll Technologies

Roll-2-Roll Technologies designs and manufactures patented fiber-optic web position sensors and advanced web guiding controllers — the precision measurement and control core of modern roll-to-roll manufacturing. Spun out of Oklahoma State University's Web Handling Research Center and trusted by Fortune 500 medical, battery, and nonwovens manufacturers, our patented sensors work without recalibration, with 0.0635 mm resolution and ±0.127 mm repeatability at line speeds up to 760 m/min — typical customer outcomes are 50%+ less downtime and payback under six months. Headquartered in Stillwater, Oklahoma, our team of PhDs, controls engineers, and industry veterans extends the sensor + controller core into complete web guide systems including stepper-motor-based linear actuators (RLA, BLA, LHS).

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