I would like to get the basics of Honing PPT

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I would like to get the basics of Honing PPT

More information about this

HONING

Honing is an abrasive machining process that produces a precision surface on a metal workpiece by scrubbing an abrasive stone against it along a controlled path. Honing is primarily used to improve the geometric form of a surface, but may also improve the surface texture.

Typical applications are the finishing of cylinders for internal combustion engines, air bearing spindles and gears. There are many types of hones but all consist of one or more abrasive stones that are held under pressure against the surface they are working on.

In terms of sharpening knives, a honing steel does not actually hone knives, but simply realigns the metal along the edge.

Other similar processes are lapping and superfinishing.

Honing uses a special tool, called a honing stone or a hone, to achieve a precision surface. The hone is composed of abrasive grains that are bound together with an adhesive. Generally, honing grains are irregularly shaped and about 10 to 50 micrometers in diameter (300 to 1,500 mesh grit). Smaller grain sizes produce a smoother surface on the workpiece.

HONING STONE

A honing stone is similar to a grinding wheel in many ways, but honing stones are usually more friable so that they conform to the shape of the workpiece as they wear in. To counteract their friability, honing stones may be treated with wax or sulfur to improve life; wax is usually preferred for environmental reasons.[1]

Any abrasive material may be used to create a honing stone, but the most commonly used are corundum, silicon carbide, cubic boron nitride, or diamond. The choice of abrasive material is usually driven by the characteristics of the workpiece material. In most cases, corundum or silicon carbide are acceptable, but extremely hard workpiece materials must be honed using superabrasives.[1]

The hone is usually turned in the bore while being moved in and out. Special cutting fluids are used to give a smooth cutting action and to remove the material that has been abraded. Machines can be portable, simple manual machines, or fully automatic with gauging depending on the application.

Modern advances in abrasives have made it possible to remove much larger amount of material than was previously possible. This has displaced grinding in many applications where "through machining" is possible. External hones perform the same function on shafts.

Economics

Since honing is a high precision process, it is also relatively expensive. Therefore, it is only used in components that demand the highest level of precision. It is typically the last manufacturing operation before the part is shipped to a customer. The dimensional size of the object is established by preceding operations, the last of which is usually grinding. Then the part is honed to improve a form characteristic such as roundness, flatness, cylindricity, or sphericity.[3]

Performance advantages of honed surfaces

Since honing is a relatively expensive manufacturing process, it can only be economically justified for applications that require very good form accuracy. The improved shape after honing may result in a quieter running or higher precision component.[3]

The flexible honing tool is a relatively inexpensive honing process. This tools produces a controlled surface condition unobtainable by any other method. It involves finish, geometry and metallurgical structure. A high percentage plateau free of cut, torn and folded metal is produced. The flexible hone is a resilient, flexible honing tool with a soft cutting action. 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.