Honing (metalworking)

Typical applications are the finishing of cylinders for internal combustion engines, air bearing spindles and gears.

It operates by using abrasive honing tools, which rotate and reciprocate inside the components, typically a cylinder or bore.

This process enhances the internal surface quality, achieving precise dimensions and smooth finishes.

These machines are essential in manufacturing for achieving high precision and consistency in parts such as engine cylinders and hydraulic components.

Advanced models, such as auto-gauging and expansion single-pass honing machines, feature automation and real-time measurement systems to further enhance efficiency and accuracy.

Typically employed in manufacturing and maintenance applications, honing fixtures facilitate the effective removal of material to achieve desired tolerances and surface quality.

[1] Any abrasive material may be used to create a honing stone, but the most commonly used are corundum, silicon carbide, cubic boron nitride, and diamond.

In most cases, corundum or silicon carbide are acceptable, but extremely hard workpiece materials must be honed using superabrasives.

Some grinders have complex movements and are self-truing, and some honing machines are equipped with in-process gauging for size control.

Then the part is honed to improve a form characteristic such as surface finish, roundness, flatness, cylindricity, or sphericity.

[3] Since honing is a relatively expensive manufacturing process, it can only be economically justified for applications that require very good form accuracy.

The abrasive globules each have independent suspension that assures the tool to be self-centering, self-aligning to the bore, and self-compensating for wear.

[citation needed] A "cross-hatch" pattern is used to retain oil or grease to ensure proper lubrication and ring seal of pistons in cylinders.

[citation needed] The plateau finish is one characterised by the removal of "peaks" in the metal while leaving the cross-hatch intact for oil retention.

Plateau honing specification:[citation needed] A profilometer provides modern, defined descriptions of cylinder bore finish that include "RPK" (Reduced Peak Height), "RVK" (Reduced Valley Depth) and "RK" (Core Roughness Depth), which is based on both the "RPK" and "RVK" measurements.