Rack Plating
Rack plating consists of placing parts on carefully designed hooks whereby the parts can be hung and remain secure while they are processed through our plating lines. This method of plating is recommend for parts with complex geometries, delicate features, obtaining scratch and blemish-free finishes, and all selective plating applications.
Hook design is critical to maximize efficiency while simultaneously providing a good conductive pathway for the rack electroplating process. A Square utilizes a large assortment of 'standard' racks to best fit a parts individual plating requirements. In addition, for large volume parts, or extra sensitive applications, we will help with the design and procurement of part-specfic racks to provide the best possible finish at the best possible price. Contact us to discuss whether rack-plating is the right plating method for your project and to discuss fixturing for your specific part.
Benefits of Rack Plating
- Produces the best aesthetic finish
- Can be optimized for parts with complex geometries
- Possible to selectively plate parts using this method
- Compatible with fragile parts
Drawbacks of Rack Plating
- Labor Intensive: Each part must be individually hung and detached from racks. This is labor intensive and typically drives up costs compared to barrel plating methods. A Square utilizes purpose-designed racks to increase the efficiency of this method. In addition, we specialize in selective plating of precious and semi-precious metals. Often we can reduce the burden of increased labor costs by drastically reducing metal costs.
- Less Uniform Plating Thickness: Unlike in barrel plating current densities vary across the face of a rack. This leads to a distribution of plating thicknesses across the rack. In situations where tight control of the metal thickness is required, A Square employs several methods to counter this phenomena. Some methods include: physical agitation of the rack, use of auxiliary anodes or "robbers", swapping parts positions on the rack mid-run, and careful control of the process parameters to improve "throw" of the bath.
- Rack Marks: Parts plated with the rack-plating method leave a witness mark from the process. In this industry this is termed a "rack mark". A rack mark occurs in the area where the part comes in physical contact with the rack hook. Physically the mark will appear to be discolored, dull, or even bare base metal. Additionally, the plating in the immediate vicinity around this mark will be thinner than the rest of the part. To mitigate the unsightly appearance of rack marks, A Square uses the thinnest gauge hook suitable for the job. In addition, we work directly with engineers and part designers to rack the part in non-critical areas or design a sacrificial tab that is removed post-plating.
Contact us to further discuss any questions, comments, or concerns, you have regarding the rack-plating process or to discuss which plating method is most suitable for your projects specific requirements.