In previous blogs, we’ve covered certain brush plating conditions the operator has direct control over to assure a quality deposit, such as: anode-to-cathode speed and plating temperature. In total, the operator has under his direct control six brush plating conditions. Besides, speed and temperature they are anode cover, voltage, replenishment of solution, and contact area.
The anode cover directly affects the deposit quality. Using the proper cover material results in optimum deposit quality, adhesion, and cohesion. Due to years of research and testing, SIFCO ASC provides recommendations for the proper cover material for each solution offered. To determine the best cover material for your application, refer to the solution’s Technical Data Sheet.
Replenishment of Solution
Maintaining an adequate amount of plating solution on the workpiece is an important controllable factor as well. As the solution is used, it is depleted of metal ions. Replenishing with fresh solution is essential to maintaining the desired deposit characteristics. Be sure to pump solution fast enough or dip often enough to keep the metal ions in the work area representative of the entire volume of solution being used.
A good deposit will be applied as fast as possible when the plating tool-to-workpiece contact area is at its optimum. Optimum Contact Area (OCA) is the best possible contact area that can be achieved, given the geometry of the surface being plated, the maximum amperage output of the power pack, and the average current density of the plating solution being used.
The proper selection or design of the plating tool is the first step in obtaining the proper contact area. The tool, however, has to be used properly, including:
Keeping the tool on the area being plated.
Keeping the tool in firm, flat contact with the area.
Standard SIFCO ASC tools are available for efficiently preparing and plating a wide variety of sizes and shapes of parts. Standard tools may be selected if they meet the following requirements:
Cover a minimum of 10% of the area to be plated, when practical.
Cover full length.
Provide adequate contact area.
Cover full length.
Allow for pumping solution when required.
Voltage is the last and most easily controlled plating condition; requiring quick, small changes made using the voltage control. Each solution is used within a certain voltage range. The rather wide voltage range is broken down according to the size of the plating tool.
Use the lower voltage range of 6 to 13 when using small tooling and plating conditions are less than favorable – such as when it is difficult to obtain optimum anode-to-cathode speed or dipping for solution rather than using a pump. Use the higher voltage range of 13 to 20 when using larger tools and plating conditions are favorable.
By controlling all six brush plating conditions, the operator can guarantee a high-quality deposit with superior adherence. If you have a high-volume operation, you may consider automating your operation. In our blog “Improved Process Capabilities Through Automation of Selective Plating,” we discuss how automation can reduce the operator tasks threefold. With an automated system, the operator-to-operator variation is eliminated, with consistent part placement, movement and pressure the same for every part.
If you have questions on how to control any of the plating conditions, please contact our Technical Service Department at 800-765-4131 or email@example.com.