Magnetic Scale vs Optical Grating Scale vs Ball Grating Scale — Pros and Cons

Many customers ask about the differences between magnetic scales, optical grating scales and ball grating scales. Which one offers higher precision and which is better for a given application? This article compares the three.

1. Appearance and structure

1. Magnetic scale: made using magnetic pole principles with magnetic material forming the scale and read head. Available in open or semi-sealed designs; S and N poles are arranged at uniform intervals along a steel tape and read by the read head.

2. Optical grating scale: uses optical glass grating as the measurement reference, installed in an aluminum profile with a read head; typically semi-sealed.

3. Ball grating scale: uses ball subdivision as the measurement standard, constructed with alloy and scale body components.

In terms of enclosure and robustness: ball grating scales are fully sealed with high hardness alloy bodies; optical grating scales are semi-sealed with optical glass reference; magnetic scales are semi-sealed or open but have rugged metal construction and widespread applicability.

2. Advantages and disadvantages of the three display types

Magnetic scale:

Highly resistant to water, oil, dust and vibration with long service life; advantages become more pronounced for lengths over 2 meters, and ranges can reach up to 40 meters;

1. High reliability: all-metal housing and imported flexible wear-resistant shielded cable with interference-resistant design;

2. High precision: selectable resolutions 1 μm, 5 μm, 10 μm or custom;

3. Price: Atonm magnetic scales offer competitive pricing while maintaining quality and broad applicability;

4. Easy installation: differential or single-ended pulse outputs; small form factor but requires flat mounting surface for accurate detection.

Optical grating scale:

1. Strong precision in the 0-2 meter range, suitable for machine tools, EDM, optical projection measurements, etc.;

2. Manufacturing becomes difficult for lengths beyond 5 meters;

3. Semi-sealed design provides some protection but oil, dust and vibration accelerate wear and shorten life;

4. Higher cost compared to magnetic scales.

Ball grating scale:

1. High precision and suitable for many machine tools;

2. Fully sealed design offers protection against water, dust and chips, providing long service life;

3. Higher price due to imported components; commonly used in lathes, milling machines and other precision equipment.

Choose based on the trade-offs between precision, environment and budget to determine the best fit for your application.