In the process of part design, various factors, such as product performance, assembly performance, etc., are usually considered to ensure that the part can meet its design purpose. However, when determining the index of part surface roughness, the potential impact of this parameter on plating quality is often overlooked. This article will explore the impact of part surface roughness on plating quality and why this factor should be taken seriously.
1. Surface roughness and polishing effect
The surface roughness of a part has a significant impact on the final polishing effect during subsequent treatments such as electropolishing or chemical polishing. In general, if the surface roughness of the part is lower before treatment, the reduction in surface roughness will be more pronounced after polishing. This means that by controlling the initial surface roughness of the part, the desired smooth surface can be achieved more easily.
2. Surface roughness and plating quality
For plating layers that require porosity quality indicators, the surface roughness of the part before plating is critical to obtaining a porosity-free plating layer. Lower surface roughness can reduce the porosity in the plating layer, making it denser. Conversely, if the surface roughness of the part is high, it is sometimes difficult to obtain a porosity-free plating layer even if the thickness of the plating layer is increased.
In addition, the greater the surface roughness of the part, the greater the deviation between the actual area of the plated surface and the theoretically calculated area. This means that the time it takes for the plated layer of the part to reach the same average thickness at the same current will depend on the surface roughness. Parts with small surface roughness will form a plated layer of the same thickness faster than parts with large surface roughness.
3. Surface roughness and plating uniformity
When the part has deep concave parts such as inner holes and internal threads, the increase of surface roughness will not only reduce the plating speed, but also significantly affect the uniformity of the coating in the deep concave parts. The large surface roughness limits the depth of the coating in the deep concave parts, thereby affecting the uniformity of the coating.
4. Surface roughness and appearance and corrosion resistance
Increased surface roughness of parts can also negatively affect the appearance and corrosion resistance of plated coatings. Parts with higher surface roughness often have a poorer appearance, and their coatings may be more susceptible to erosion and corrosion by environmental factors, reducing their corrosion resistance.
5. Conclusions and recommendations
Unless the surface roughness of the part has special requirements for the performance of the product, the surface roughness of the part before plating should be reduced as much as possible. Practice has proved that the use of profiles with high surface quality, the manufacture of blanks of parts by precision molding technology, and the reduction of the roughness of the cutting surface can significantly improve the quality of the coating on the surface of the part, reduce the generation of non-conforming products, and reduce the total manufacturing cost of the part. Therefore, designers and manufacturing process personnel should jointly recognize the importance of part surface roughness to plating quality to ensure the performance and reliability of the final product.
