Serious Education ... plus the most fun you can have in metal finishing.
Tin/Lead Plating of Prototype Print Circuit Boards(2000)
Please help! I need to TIN/LEAD plate our prototype and small production printed circuit boards and need a simple yet effective chemical formula and mixture to have an Electroplating tank in which I can plate the pc boards. I have a suitable 6 volt/40 amp rectifier and all the necessary 40-Gallon containers in which to mix the chemicals. I have smaller tanks 22 gallon as well. I have access to any size tank for that matter but simply need the chemicals required to obtain a plating solution, how to mix them together and the quantities required to be mixed together in order to have a working Electrolyte solution as I said before.
Thank youChristopher Halgryn
Fjord Electronics - Auckland, New Zealand
Your post here leaves out some essential details, like what volume production you are looking for. My gut reaction is to look for a proprietary formulation; you will buy your lead and tin soluble salts (tin and lead fluoroborates probably, plus boric acid) as a commodity and get an additive from a supplier. Run the bath according to the supplier's recommendations. In this, I am assuming that you want to reflow the Sn/Pb for a final surface finish. If so, I would recommend that you also get a good proprietary solder conditioner to use after final etching, especially if you use an ammonia etch.
If the Sn/Pb is not to be reflowed and used as a final finish, I would recommend that you use a straight tin sulfate plate. Control is easier, and you don't have to worry about the lead liability.
The last time I produced a board with a Sn/Pb reflow final finish was in 1990 for a military spare part. You might want to talk with the customer to see if a reflow finish is what they really want. You might be better off with soldermask over bare copper or an alternative finish (one not using Sn/Pb). PCB final finishes is a concern of mine, so post any further questions here and I'll get back to you.
- Tallahassee, Florida
Sir Thank you kindly and a big apology for not replying sooner as I had a lot of other projects and PCB's to design and manufacture. Now James, I appreciate your explanations and what I am really looking for is a chemical or formula I need to prepare myself to simply "TIN PLATE" certain PCB's.
I made a mistake by purchasing the Fluoboride,Borax! all the rest of the chemicals but I did not realise I needed to have a THP plant with RECTIFIERS several large trays or containers to hold the various chemicals even built a 5 VOLT 35 AMP rectifier and all that is required for tin Plating.
I simply need to use a system whereby I will be able to "APPLY" the TINNING chemical to the boards by perhaps brushing it on with the best of FINE brushes or, By means of using a system by electroplating the board all I really need is to "TIN-PLATE" as I mentioned some PC Boards.
At the moment we have a large heavy LEAD/TIN roller where the lead is held in a large tray at the bottom with plated rollers rolling through the moulten lead/tin solution. At the top there is a large silicon covered roller that revolves and turns around so by placing and feeding the PCB from the back between the top silicon covered roller and the large tin plated roller you push the pcb's from the back between the two rollers and it rolls to the front plating the pcb.
Before you roll the PCB through the two rollers you obviously apply a tinning chemical to the copper side of the pcb. Almost like the Plumbers that apply a bit of spirits of salts to say a piece of galvanized iron before soldering.
I honestly hope you do not feel upset and tell me you know what I am talking about believe me there are people in this world that has never heard of roller plating PCB's like I do.
Again Sir, Thank you for the reply and I am waiting in anticipation for your reply when convenient and in your own time again,.........Thank you
Please advise me the easiest way to achieve TIN Plating my pcb's.
We are from SWEDEN originally now living in Auckland New Zealand for almost 10 Years now.
Fjord Electronics & Designs Inc - Auckland, New Zealand (Ex SWEDEN)
James offers good advice in suggesting that you buy a proprietary tin plating solution because not only will it work better and you will receive technical advice from the supplier. You are bound to have some difficulties, and then where will you turn? Even large plating shops don't formulate their own solutions.
If you insist on formulating your own plating solution, however, you will find formulations including the required additives in N.V. Parthasaradhy's "Practical Electroplating Handbook".
Ted Mooney, P.E. RET
Pine Beach, New Jersey