A Basic Guide To Engine Valve Grinding Machines

What is lapping?

A machining process where two surfaces have an abrasive between them while they are rubbed together slowly using a machine or hand is called lapping.

There are two forms of lapping and these are grinding and cutting of a harder material using a softer material.

1. Hard material

In grinding, glass or any other brittle material is rubbed against another surface which could still be glass or iron.

The material which is rubbed on is called the grinding tool or lap.

The movement of glass on the iron or glass is carried out with an abrasive between both surfaces, which includes:

• Silicon carbide

• Optician’s rouge

• Emery

• Diamond, etc.

As a result, microscopic conchoidal fractures are produced due to the movement of abrasive between the two surfaces and the removal of material from either material.

2. Soft material

The second form of lapping takes advantage of a softer material such as a ceramic or pitch which will be rubbed on and in this case, is the lap.

The material is charged with abrasive to enable it to cut a harder material.

What is valve lapping?

Valve lapping is a process that ensures a perfect fit for the intake and exhaust valves in the engine cylinders on their seats. Usually lapping is performed after performing an engine overhaul, or when the old valves are replaced with new ones.

Lapped valves provide maximum tightness in the combustion chamber, ensuring the engine normal operation and its technical characteristics, a high level of compression, and engine efficiency.

If valves are not lapped, then some energy of the burned gasses will be lost and it will not give the engine enough power.

The importance of valve lapping machine

Grinding with a valve lapping machine can make the valve sealing surface obtain high dimensional accuracy, geometric shape accuracy, and surface roughness. After grinding the valve sealing surface can usually achieve a dimensional accuracy of 0.001mm ~ 0.003mm; geometric shape accuracy (such as unevenness) of 0.001mm. the grinding project, the research tool, and the sealing surface is well fit together, the research tool along the fit surface for complex grinding motion. Abrasive is placed between the grinding tool and the sealing surface. When the grinding tool moves relative to the sealing surface, some of the abrasive particles in the grinding tool slide or roll between the grinding machine and the sealing surface, cutting off a very thin layer of metal on the sealing surface. The convex peaks on the sealing surface are first ground away and then gradually reach the required geometry.

Grinding is not only a mechanical process of abrasives on the metal but also a chemical process. The grease in the abrasive accelerates the grinding process by forming an oxide film on the machined surface.

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