Etching processing is a customized machining method for thin metals. For some parts with high precision requirements, the tolerance is tight. The following content will let you know what factors are related to machining accuracy.
- Metal material
Different materials have different etching effects and etching rates under different chemical conditions. Such as stainless steel and aluminum, under the same conditions, the accuracy will be very different. Typically, stainless steel and copper are etched with ferric chloride acid, while aluminum is made from acid and base. Under the same etching conditions, the precision of stainless steel will be higher.
- Etching speed.
In order to ensure tight tolerance, one of the necessary conditions is to maintain a balanced etching rate on the surface of the part during the processing of the etching solution. So, it is necessary to strictly control the density range of the chemical components of the etching solution; keep the temperature distribution of the etchant in each part of the tank equally; keep the concentration of the etching solution in each part of the etching tank evenly. The former can be controlled by analyzing the etching solution, and at the same time, a large volume of etching solution can be used when the cost allows; the latter two should be satisfied by the method of stirring the etching solution. The faster the etching speed, the greater the amount of metal etching per unit time, which will increase in heat. The rapid temperature changing of the corrosive solution, which is not conducive to the constant etching speed and difficult to control the processing of parts with very precise depth requirements. In practical applications, for those parts with a large etching area, the method of “fast first and then slow” can solve the problem. It is to use the etchant with a faster etching speed to engrave for the first time. When the etching depth is close to the design required data, then switch to a slower etching speed for precision etching. Although this etching method increases the steps, photo chemical etching time is shortened, while the etching precision and surface gloss are good.
- Side Etching
The relation between the side etching and the etching depth:
The size of the side etching R angle is affected by the etching depth, the ratio of the minimum width of the cut-out hole and depth, the composition of etchant , etching method and material type.
The amount of side etching determines the precision of chemical etching machining. The smaller side etching, the higher etching accuracy and the wider the scope of application.
On the contrary, the machining accuracy is reduced, and the scope of application is reduced. The side etching is mainly affected by the metal material. Among the metal materials, copper has the smallest side etching, and aluminum has the largest side etching. The selection of etchant, concentration and etching conditions also have a large impact on metals. Under normal circumstances, people think that the faster the etching speed, the smaller the side erosion.
In fact, this understanding is not very accurate. It is only established when the composition of the row material and the etchant are certain.
However, the minimum side etching can only reach the theoretical value of this metal material. Studies by relevant scholars have shown that choosing a more superior etchant can indeed improve the side etching of the metal, although the increase in the etching rate is not obvious.
- Etching Depth
This is the factor that all the various factors have the most influence on the tolerance of chemical etching processing, because the deeper the etching processing depth, the longer the part is immersed in the etching solution, and the longer the time, the greater the change in the various chemical components in the etching solution. , which further increases the variation in etching rate and etching effect. At the same time, when the etching process is too deep, when it reaches a certain depth, the etching will also change due to concentration polarization and the deposition of etching residues, and the tolerance of chemical etching processing will be greater.
- The Etching Machine
The quality and life span of the etching machine is directly related to the precision of the products produced by the etching process. Accurate equipment, stable system operation and well-proportioned spraying system will directly affect the accuracy of the product. Imported etching equipment has been introduced to ensure that the precision of the produced products fully meets customer requirements and mass production is carried out stably.
- Photosensitive Photo Resister
A good photosensitive photo resister will have a better developing effect, and the thickness of the coating will also affect the etching accuracy.
- Initial Formwork Manufacturing
At present, the Mylar film template and the glass template are used. These two templates have a direct impact on the exposure accuracy, because the expansion coefficient of the film template will be larger, which will affect the exposure accuracy, and our glass exposure template can basically ignore errors and realize fully automatic production, avoiding the influence of manual operation.
- Related to dust-free purification workshop
Because all processes need to prevent dust from falling onto the surface of the metal sheet. Etching can cause some white spots and pits on the product if dust-like particles adhere to the surface. For example, spots and pits will enlarge the size of gap, which will seriously affect the appearance and precision of the product.
The above is the introduction about the factors related to the photo etching accuracy. Hopefully it can help you. If you have any questions about the content of the article, you can call us or leave us a message: [email protected]