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Precision Balls 101 - Picking the Best Materials for the Job

Choosing the Right Precision Ball Material

When selecting precision balls for an application, the material is one of the most important considerations. The material determines the properties and capabilities of the balls, and each material has ideal uses based on factors like hardness, weight, corrosion resistance and cost. Here is an overview of common precision ball materials and their typical applications:


Steel balls offer excellent hardness and durability. They are able to withstand high loads and resist deformation under pressure. Steel is easy to manufacture into precision spheres and is relatively affordable. Typical applications include ball bearings, valves, casters, and linear motion components. Downsides are steel's tendency to rust and its high density compared to other materials. Popular grades are chrome steel, stainless steel and carbon steel.


Synthetic ruby has outstanding hardness, second only to diamond. It is highly resistant to wear and can maintain excellent sphericity and surface finish over time. Ruby's low density also minimizes momentum. These properties make ruby an ideal material for ball bearings in precision instruments and other applications that require extreme precision. However, ruby balls are significantly more expensive than steel.


Ceramic materials like silicon nitride, zirconium oxide and alumina are known for being lightweight, hard, corrosion resistant and able to withstand high temperatures. They are a good option when high hardness is needed but steel and ruby are too heavy. Common uses are in ball bearings, valves, pumps and medical instruments. Cost is moderately high but lower than ruby.


Plastic precision balls encompass many polymer-based materials. They provide good corrosion resistance and a low coefficient of friction. Density is very low compared to metals, making plastics suitable for light loads where minimizing inertia is beneficial. Acetal, nylon, PTFE and ultra high molecular weight polyethylene are frequently used for applications including medical equipment, electronics, conveyors and gaming.

By understanding the unique properties and ideal uses of materials like steel, ruby, ceramics and plastics, engineers can select the optimal precision ball composition for their specific application and performance requirements. Consulting with reputable manufacturers is also advised when choosing a ball material.