What are the limitations and difficulties of chemical etching process in terms of processing

Chemical etching processing can only take the original surface state of the part as a benchmark, progressive cutting. The shape and surface state of the part after chemical etching processing is directly related to the original shape and surface state of the part. Chemical etching processing also has its own process limitations, mainly the following points:

First, chemical etching can not be used for surface roughness of the plate, bar, etc. to process the complex shape of the parts. Such as the need for complex parts on some parts of the processing of a very thin web goods some shallow flange, it is necessary to first use the mechanical way all the geometric shape of the processing to a certain extent, and the next chemical etching is only parallel to the surface has been processed to the metal uniformly etched off a layer, in order to achieve the required thickness and shape.

Second, chemical etching can not be used to process structural parts with very tight tolerances. The adhesion of the graphic anticorrosive layer and changes in the composition of the corrosive agent in the process will cause changes in the corrosion coefficient. The geometry of the chemically etched edges can also have certain deviations. It should be noted that: chemical etching can not be used to process narrow and deep grooves, this is because in the chemical etching reaction generated by the bubble will be gathered in the edge of the layer of corrosion protection below, and these are plugged in the layer of corrosion protection below the bubble in fact played the role of the metal surface in the corrosive agent to isolate the role. At the same time, the role of the etchant surface tension, also in the narrow or small radius surface caused by the etching can not be carried out. For the depth of the larger groove processing requirements for the width of not less than 4mm, for the depth of the groove or round hole requirements for the width or radius is not less than 1.5 times the depth.

Third, the chemical corrosion method of drilling processing, chemical etching drilling and mechanical methods and the method of drilling holes are not the same, it can not be processed out of the latter two can be processed out of the hole shape. Chemical etching drilling can only drill irregular conical holes, for the depth of chemical etching drilling due to etching time is long, so that the tolerance increases, so chemical drilling is seldom used except in special circumstances.