The State of Plating

Estimated reading time: 3 minutes

The current market for selling plating lines for panel and pattern plating circuit boards in Europe is not exactly huge. Since I have been involved in selling this type of equipment, the company I work for has probably averaged the sale of one machine per year.

Normally, this has been due to the replacement of completely worn-out equipment or reinstatement of a factory after a fire. Within the last 12 months, we have sold the first line based completely on the requirement for advancing technology. Although this sample group is not large enough to see any real trend, I have a feeling that the European PCB industry is likely to see an increasing demand for machines that can achieve results to meet the demands of the newest ideas for electronic printed circuit design.

Examples

We rarely have a blank canvas to work with. In nearly every case, we must try to fit a quart in a pint pot. Space is the enemy when it comes to integrating the best available new technology into the footprint of the previous 20-year-old plating line. To make matters worse, it is not unusual to be asked to increase the output capacity of the equipment at the same time.

Increasingly, PCB design technology utilises buried and blind via holes and plated via fill is also becoming more and more common. The buried and blind holes mean that the loading on the plating equipment is multiplied by the number of different inner layer connections. The same technology means that equipment needs to deal with thinner and thinner materials.

Plating copper via fill typically means the tank design must be larger, so it takes up more of the valuable space available and takes a long time compared to a traditional throughhole cycle. A typical through-hole plate might take 45–60 minutes where a via hole run could be 3–4 hours.

It is well known that the size of PCB factories in Europe is usually much smaller than the factories in Asia. Typically, this means there is only a single plating line available to production, and this one piece of key equipment must cover every type of work which goes through the factory. Compromises must be made, and usually, it is the work at the extremes of capability that suffer. For example, very thick heavy panels are hard to transport using commonly used top-clamping methods (they can drop out of the clamps unexpectedly). Very thin panels need extra support to stop them folding when they are dipped into the tanks and also to keep them in a stable position in the centre of the tank between the anodes (the plating will be too heavy on the side closer to the anodes and too thin on the side which is further from the anodes). For both problems, simple solutions are available, but the same fix does not suit both extremes at the same time.

The plating chemistry has also advanced when compared to the simple solutions and replenishment additives of years ago. Again, the major problem for smaller manufacturers is the sheer amount of variation in the work they have to put down the line and the fast turn arounds required by customers that prevent them from batching similar work together. The chemistry in a bath can definitely be tuned to provide even plating of a large area, such as panel plating where the whole surface of the panel is plated as well as the through-holes, but the same tuning is likely to make it very difficult to plate isolated details or very small plating areas. In the worst case, the additives have to be stripped out of the solution using a carbon filter and then added again to suit the next requirement.

Solutions and Developments

All of the previous cases are real examples I have come across during the last year, and they are very big problems for the companies involved. In some cases, the only practical solution is a larger factory and a second special-purpose plating line. Development of hardware to meet the needs of the large range of challenges facing the plating operation has recently been quite strong. There are a number of features becoming more commonplace on new equipment and some that could also be retrofitted to existing equipment.

To read the full article, which appeared in the August 2019 issue of PCB007 Magazine, click here.