Chemical and electrolytic etching have been in use as the fundamental technology in all areas of applications in electronics, precision machinery, and printing industries. In some application areas etching has been found obsolete by the emergence of more advanced technologies, but etching still remains to be an important processing technology. Some examples are introduced below.

(3) Production of precision machine parts by etching

Most precision machine parts are produced by mechanical machining processes, but etching is more advantageous for the parts that are hard to produce, difficult to obtain required accuracies, small prototype production lots, and cost intensive parts due to expensive molds required.

In most cases, metal plates in thickness of 0.1~1.6mm are used for precision parts production by etching. The material can be SUS304, permalloy, silicon steel plates, and SUS316 as required for each application.

An outer blade section for electric razors is a familiar example for etch created products. These are made of 50~70μm thick SUS430 (13Cr) plates, and some techniques to improve the cutting performances were devised into the process. For instance, the holes are created by etching from one side first, then a press is used to make the hole edges sharp. Another is called "W etching" where slightly larger (10~20μm) pattern is deposited around the holes from the reverse side and hard chrome plating is deposited onto these narrow areas to improve the cutting performances. However, these methods are obsolete today, replaced by Electroforming techniques. The new methods utilize copper sided PCBs with 35~70μm copper plates. A negative pattern of the blade is exposure created on the copper, etching is used to remove the copper portion other than the blade pattern, then the blade is electroformed 50~79m thick onto this mold. The electroformed blade is removed from the mold and processed in a press to become the complete product.

Following are the application examples.

1) Measurements
Strain gauges, galvanometer mirror frames, electrical contacts and terminals, gaskets for meters, etc.

2) Electronics industry
Shadow masks for CRTs, high density electrical connectors, various metal grids, jigs for ceramic capacitors, magnetic recording heads, etc.

3) Optical instruments
Shutters/apertures/various slits for camera, etc.

4) Others
Precision micro nozzles, vibration plates, micro fine filters, bases for industrial diamond cutters, carriers for silicon wafer grinders, etc.