Process Engineering: PCB Manufacturing’s “Delta Force”

Source:Edadoc Time:2017/4/12 0:00:00
The role of the process engineer is arguably one of the most important jobs in the printed circuit industry. The process engineer is on the front line of manufacturing and responsible for making sure product yields and profitability meet expectations. The job typically entails and intertwines many different and even disparate disciplines, including: electrochemistry, mechanical engineering, NC machining, robotics and automation, metallurgy, laser technology, polymer processing and photolithography. It even reaches back into the printed circuit design process. Because of this variety, it is also arguably at once, one of the most challenging and interesting jobs in the PCB industry.

In practice in most major manufacturing facilities, process engineers often specialize in just one of the areas identified here. In smaller facilities, the process engineer often must move between and attend to matters in more than one discipline, most commonly process steps which immediately precede or follow the area where the engineer has special training and expertise. However, in many cases, factors which may influence product quality and yield may be several steps earlier or later in the process. This is extremely important when one is looking into, or in the midst of implementing a new process on the manufacturing floor. Change comes slowly in PCB manufacturing and old habits are hard to break, so keeping a finger on the pulse of the process is critical.

It is a simple fact of life that in PCB manufacturing, process characterization, monitoring and maintenance are critical to success, and so also is collecting and evaluating data on process health. The tools and specific methods and measurements required will vary significantly from process to process, but without control, the quality of the results of the process will be left to a roll of the dice. One of the most important skills a process engineer should master is learning how to properly design experiments to identify the optimal operating parameters for the target process. Selecting which variables to monitor and optimize is critical. One must first do the right things and then do things right. Pick the wrong ones and the data collected will likely be meaningless. And this begs the question: How does one choose variables to monitor in an experiment?

We are fortunately living in a time when there are oceans of experience in most of the processes used in circuit manufacturing, so tapping into that experience is important. There is no benefit in repeating experiments that have been run countless times before. In this regard, it is very important that the process engineer be at least as much a reader as an experimentalist. Running experiments is useful and can be engrossing but if the answers are known by others, it is better to tap into their knowledge base.

There is the old story of the successful individual who was queried as to the most important factor in their success. The two-word answer was “good experience.” When pushed to explain how one gets the necessary good experience another two-word answer was given: “Bad experience.” This apocryphal story was no doubt concocted by someone who understood the importance of learning from experiences and of the importance of failure. If we, in our infancy, were afraid of falling on our behinds as we departed infancy and attempted to walk, we would still be crawling about on our hands and knees. To this end there is the reminder from another sage, the early 20th century polymath and philosopher, G.K. Chesterton, who wrote: “Anything worth doing is worth doing badly.” What is missing and must be inferred as an addendum to his message are the words, “…at first”. There is nothing wrong with mistakes; mistakes are how we learn. However, if one has the resources available to them to avoid mistakes, then it is folly not to avail one’s self of that information.

There are, of course, numerous other repositories of process knowledge available. One easily overlooked are the individuals who represent the process or equipment developers. These individuals are the honey bees of the industry who help cross pollinate those within the industry with new ideas, transferring knowledge and experience between manufacturers to the betterment of all.

In summary, process engineers serve a vital function on the front line of printed circuit manufacturing. They are often, if you will, the “Delta Force” that subdues and controls that which is one of the mortal enemies of manufacturing…process variation. The intelligent process engineers should avail themselves of all of the tools they need to complete their mission.

This article originally appeared in the April 2016 issue of The PCB Magazine of icconect007