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March 2015 • The PCB Magazine 79 within +/– six standard deviations, or six sigma levels. As Figure 2 indicates, the tails are con- tained within the spec limits, assuring that vir- tually no product will be produced out of speci- fications (3.4 DPPM, or two defects outside each spec limit). It's Ok To Take Baby Steps The key takeaway here is that improvement should be taken in steps; don't expect to jump from three to six sigma overnight. Sigma lev- els range from one to six, and legitimate pro- cess improvement generally follows a natural progression from the current level up through this range. The first step is to make sure you are at a true three sigma level; most organiza- tions are surprised to learn that they have a lot of work to do to reach this plateau. The next step is to make incremental improvements to begin moving up the sigma ladder. Quantum improvement can be realized by moving up just a single sigma level; remember that the key to success in improvement is to hit singles, not home runs! Given the zero defect goal discussed here, and the general perception that six sigma lev- els are unachievable, I thought it appropriate to close with the following quote from the chief engineer of Toyota's first Lexus; a man called the "Michael Jordan of chief engineers": "Even if the target seems so high as to be un- achievable at first glance, if you explain the ne- cessity to all the people involved and insist upon it, everyone will become enthusiastic in the spirit of challenge, will work together, and achieve it." –Ichiro Suzuki, Toyota Motor Corporation PCB figure 2: Tails are contained within the spec limits, assuring that virtually no product will be produced out of specifications. Steve williams is the president of Steve williams Consulting LLC and the former strategic sourc- ing manager for plexus Corp. he is the author of the books, Quality 101 handbook and Sur- vival Is not Mandatory: 10 Things Every CEO Should Know about Lean. To read past col- umns, or to contact williams, click here. BEST PRACTICES 101, PART 5: PROCESS CAPABILITy continues Point oF View