Strip plating thickness problem

A. In your case, by adjusting current density and feed speed it is hard to achieve thickness requirement of the copper and tin at the same time. Practical way is lower your feeding speed and shorten copper plating distance by cutting the quantity of copper plating cell (let's say in your process, you have 4 plating cells for copper, but this time you only put current in the last 2 cells.).

A. Hi Dhanajay. How are you!
Achieving desired result in Continuous reel-to-reel plating is all about:
1. feed speed adjustments
2. plating speed or plating efficiency of the bath
3. no. of plating cells and their length
4. current carrying capacity of the bath (the more the better)

Here in your case as John Hu rightly said
1. reduce (current off) no. of cells of acid copper
2. increase no. of tin plating cells.
3. adjust current.
4. calculate and adjust the feed speed though in this case it may not be advantageous.
5. look for high current carrying (high speed) plating process. There are supply houses who offer high speed tin plating process.
Regards