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One of the most systematic and successful approaches to the challenge of cycle time reduction can be found in the principles and tools of lean six-sigma methodology. The success of this strategy requires commitment. It is not a quick fix, nor will it be effective if it is only used as an occasional housecleaning activity. To be successful requires a long-term commitment of time and resources and a tireless dedication to improvement. As a result you should expect and welcome change as your company focuses from inward (my product) to outward (my customer), with a goal of total customer satisfaction. It's a win-win solution.
Some might argue that Walter Shewhart was the inspiration for the concept of six sigma. It was Shewhart who in the 1920s identified common and special cause process change and introduced the control chart. The credit however for the term "six sigma" is given to Bill Smith and co-founder Dr. Mikel Harry of Motorola. In the mid-1980s, Motorola CEO Bob Galvin supported a quality initiative based on six sigma methodologies that changed the way Motorola did business, which improved quality, increased customer satisfaction and ultimately saved hundreds of millions of dollars in the process.
Motorola's six sigma concept began with four basic principles: measure, analyze, improve, control (MAIC). The D (define) of DMAIC was added later by GE. Today, six sigma includes lean principles as well as methods that introduce six sigma earlier into the design phase of the process, which enables faster time-to-market with products that better meet the customers’ specific requirements. By using six sigma principles and lean techniques together, PCB manufacturers can reduce both process variation and cycle time together effectively.
Getting Started
The PCB manufacturing process is by nature a batch process, following a predetermined sequence that is developed to meet the products’ specific design requirements. In PCB manufacturing not all products go through the exact same process, which complicates the task of cycle time reduction. As an example, a standard multilayer board will probably not be laser-drilled or plasma-etched unless it has some very unique characteristics. And HDI products may cycle through lamination, drilling, laser drilling, plating and etching two or more times before moving on to solder mask application. Cycle time reduction efforts for these two products will require individual evaluation.
Editor's Note: This article originally appeared in the October 2015 issue of SMT Magazine.
