What is the Lapping Process - Difference Between Lapping and Polishing

Some types of CNC machined parts need to achieve close tolerances, so a surface finish is required. There are various finishing operations like polishing, buffing, and lapping. In this article, we are going to talk about what is lapping process, is and what is the difference between lapping and polishing.

What is the Lapping Process - Lapping Process Types and Applications

The lapping process is a surface finishing process, in this particular process, the tool and the workpiece will form a lap joint and there will be some sort of abrasive particles in between these two mating surfaces. The abrasive powder will be aluminum oxide, jeweller’s rouge, optician’s rouge, emery, silicon carbide, or some sort of crystalline structure, in between the tool and the workpiece, the tool overused is the plate. The lapping machine will be a circular plate, which is made up of cast iron and rotate at slower speeds. there will be pressure exerted on the workpiece and it will push the workpiece against the rotating plate, then particular abrasive particles remove any of the irregularities on the surface of the workpiece and will give the desired surface. The lapping process does not produce any sort of heat as there will be heat generated so this is the reason there will be no stresses induced.

There are two types of the lapping process, the first one is conventional lapping which is of the hand or manual lapping, and the second one is automatic lapping, which can be carried out by using a specialized machine. In the hand lapping process, the workpiece is pressed manually against the rotating tool which is a cast iron plate, and that overall operation is carried out manually, there will be some sort of arrangement for moving the workpiece on the surface of the tool.

When it comes to its applications, the lapping process is usually used in glass machining, ceramic materials machining, and some sort of brittle material machining.

Difference Between Lapping and Polishing

Lapping refers to the finishing of the machined surface by the relative movement of the lapping tool and the workpiece under a certain pressure using the abrasive particles coated or embedded on the lapping tool. Lapping can be used to process metal and non-metallic materials. The machined surface shapes include plane, internal and external cylindrical and conical surfaces, convex and concave spherical surfaces, threads, tooth surfaces, and other profiles. The machining accuracy can reach IT5-01, and the surface roughness can reach Ra0.63-0.01μm.

The electrolytic polishing takes the workpiece to be polished as the anode, and the insoluble metal as the cathode. The two poles are immersed into the electrolytic cell at the same time, and the DC current is used to generate selective anodic dissolution, so as to increase the brightness of the workpiece surface and achieve the mirror effect. Electrolytic polishing can not only deal with stainless steel parts of any shape and size but also can polish precision parts and various small and high-precision parts. The operation process is simple, the cost is low, and it can also replace the passivation treatment.

Lapping process will generally leave a smooth and unpolished surface and polishing is typically one of the last processes in manufacturing.

What is the Lapping Process – Difference Between Lapping and Polishing

What is the Lapping Process - Lapping Process Types and Applications

Difference Between Lapping and Polishing

Related Articles：