Think & Tinker Instrument Prototyping

Think & Tinker, Ltd.
P.O. Box 1606, Palmer Lake, CO 80133
Tel: (719) 488-9640, Fax: (866) 453-8473
Sales: Sales@thinktink.com, Support: Support@thinktink.com

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Tin/Lead Electroplating Module
-Hull Cell/Principle of Operation

The Hull Cell
The brightener/leveler formulation developed by Lea Ronal is a two part part additive system that functions to smooth out and distribute the solder plated onto the surface and in the holes of a PCB. At the current time there is no simple test to directly analyze the additive or carrier levels in the bath or to determine if they are in balance with the other functional constituents. There is, however, a rather simple technique to infer when the additive level needs attention and to determine just how much material to add. This technique uses a miniature plating cell commonly known as the Hull Cell. Using the procedure described below, the cell is used to test plate a series of sample boards to determine when the bath needs adjustment, and, when used with the above analytical techniques, to determine how much of to add. PC SolderOn Carrier is normally maintained through routine replenishment of PC SolderOn Additive which contains small quantities of Carrier.

Principle of Operation
The Hull Cell is intended to act as a quick check on the health of the tin/lead plating bath. Using the cell in conjunction with the chemical analyses it is possible to qualitatively and quantitatively analyze all of the major constituents of the bath.

When filled to the line marked on the side of the cell, the volume of the test sample is 267 ml. If we denote:

V=volume of main plating tank (liters)
H=amount of addition agent added to Hull Cell to produce acceptable test plate (milliliters)
C=amount of addition agent needed by main tank (milliliters)

the multiplicative factor that relates what you add to the Cell and what you will need to add to your plating bath is given by:

C = (V/0.267) x H

Equipment Required:

No. 267 Hull Cell
Copper test plate
Corrugated solder anode

Reagents Required:

5 cc syringe of SolderOn additivet

Procedure:

Read the manual that came with the Hull Cell carefully before testing your bath! Or you can not read the book, flounder around for half of the day, burn up $25 worth of test plates, and still not know what is going on. READ IT.
If this test is being conducted prior to using the bath for the day, dummy plate a test board (i.e. plate a piece of scrap copper for about 45 minutes). It is important that the bath be adequately stirred up and filtered and that the copper level adjusted by dummy plating before using the Hull Cell.
Flip the main power switch OFF.
Rotate the pump valve to DRAIN (fig. 6).

Established 1990

On the web since 1994