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The Technique of Lapping

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The Single-Plate Lapping Machine

The single-plate lapping machine is finding a wide and ever-increasing range of applications. According to the desired surface quality, will result in a lapped or polished look. The agents that are used during this machining process depend on the abrasive grain, the amount of material removal, and how flat and fine surfaces of the workpieces are achieved. Some examples of abrasive grain that are commonly applied to the rotating plate are silicon carbide, aluminum oxide, and other types of abrasive particles. Below’s a description of this machine and the working principles and applications.

As in all machining processes, the operations are all conducted with specific objectives. In order to maintain control over the different factors influencing the quality. These factors are four in number:

  1. The flatness of the lapped surface is theoretically a copy of the lapping plate. The lapping plate is continuously flat by the conditioning rings.
  2. Ensuring the parallelism and dimensional uniformity of workpieces is by the flatness of the pressure plate and by interchanging the workpieces.
  3. Achieving size accuracy by the precisely controlled removal rate per unit of lapping time.
  4. Determining the surface finish goes off of the grit type, lapping fluid (film), and pressure.

In modern lapping machines, the material removal rate is high enough to make lapping a serious competitor to grinding in many cases. In contrast to grinding, the same grit and the same lapping medium can be used for a wide range of materials. The fixtures used for lapping are generally simple to make, and therefore inexpensive.

Flat Surfaces

Nowadays, workpieces commonly deliver for finishing with a machining allowance of 0.2 to 0.5 mm. So the implementation of lapping can be directly after turning, milling, punching, or sintering, except in the case of a large area, solid workpieces, as these workpieces require longer machining times (large chip volume). Components with large recesses, such as covers, housings, flanges with recesses or holes, rings, etc. often provide large machining allowances. In such cases, lapping is frequently much faster than grinding. There is no “grinding in air”, while the entire workpiece surface is machining at the same time. The beauty in our lapping and polishing fixtures.

Lapped and Polished fine surface parts on single sided lapping machine

Figure 15:
Assortment of workpieces
machined on a single-plate
lapping machine. However,
relatively tall workpieces and
workpieces with complicated
shapes can also be machined.

The main factor contributing to the success of the single-plate lapping machine (Figure 16) is the effect of the conditioning rings, which keep the lapping-plate surface flat during the lapping process. The single-plate lapping machine is in fact the only machine tool for general use. That being said, it is capable of continuous self-correction for maintenance, or even improvement, of operating accuracy. The accuracy of all other machine tools decreases with each second of use unless the errors are compensated or corrected by means of additional equipment or measuring controls (it is worthwhile to make cost comparisons).