March 20, 2018
The Top 10 SPC Mistakes: Part 4
Okay. A quick rundown of what we’ve covered so far in our list of Top 10 Mistakes to avoid when using statistical process control (SPC): training everyone, charting everything, segregating control charts from manufacturing, “pinching” the SPC coordinator, using SPC because it’s a “good thing to do,” and using SPC as a data collection exercise. Let’s continue with our list.
Wait, I thought you were done…there are more? Okay, let’s do this thing.
Yeah, there are more. And then a few more after this. We’re getting to the really meaty stuff. Stay with me. But remember (disclaimer time again), please do take the right steps that all the experts in all the books discuss, and don’t commit the mistakes I’ll be listing in this blog and the rest of the series
So, let’s continue on with our list of Top 10 Mistakes
to avoid when using SPC...here are numbers 4 and 3.
4. Providing minimal or no infrastructure/support
I have encountered numerous SPC implementations in which the operator had no idea what was expected of them or the system, much less how to interpret plot points on a control chart. At one large consumer product manufacturer, the infrastructure was present (computers, software, gauges, etc.), but the operators weren’t trained in SPC or on how to interact with the system. Engineers on the shop floor were also puzzled and neither camp understood the statistical analyses that their software performed. With virtually no support, the result was a lot of eye-rolling, a lack of interest, and very little use of the “system.” Why then, did they even put SPC on the shop floor? “Because our customer said we had to,” was the response from the company’s IT staff. In this case, the infrastructure was present, but support was virtually nonexistent, making for a lousy SPC system.
To systematize any change and ensure its long-term viability, there must be investments in support and infrastructure. Whether it’s a new accounting system or shop floor SPC, the same holds true. This doesn’t necessarily translate into pouring a huge budget into an SPC system; some superb SPC systems I have encountered were inexpensive, relying on paper and hand-created control charts.
In fact, expenses like these were the extent of one company’s “hard” investment in its SPC system. Its “soft” investment was engineering and quality support on the shop floor combined with excellent, periodic SPC training. Regardless of a company’s budgetary situation, an SPC system must have a means of ongoing support and an infrastructure with which to interact. An SPC system’s infrastructure equates to the tools that are placed in a worker’s hands, as well as the support that’s placed in their heads.
So what tools should shop floor workers be given to maximize the effectiveness of an SPC system? From an infrastructure standpoint, it can be anything from simple spreadsheet to a full-blown, automated and computerized system. Computerization requires hardware (shop floor computers, connections, gauges, databases, and the like). What’s placed in the operators’ hands is the easy part. The hard part is what’s placed in their heads. For example, in addition to the requisite statistical knowledge, operators must know how to navigate the software and understand the basics of a personal computer.
Shop floor personnel must also be supported from a technical standpoint. This technical support should include at least computer and process engineering expertise coupled with statistical support in the form of training. Don’t assume that these areas of expertise require an individual for each. Most implementations I have seen include a jack-of-all-trades—a support person whose knowledge encompasses most or all of these areas of expertise. Lastly (and most importantly), management also must honestly support SPC efforts. Without management interest and support, those infrastructure and support expenses could quickly go to waste.
3. Making production a priority over quality
The statements, “Just ship it!” “Get it out the door!” or my personal favorite, “Let the customer worry about it!” seem to be outdated phrases uttered during a bygone era. Archaic? You bet. Alive and well? Unfortunately, yes. These phrases reveal a manager’s production-biased psychology and that product quality isn’t nearly as important as some short-term reward. In this case, management believes that the long-term consequence of losing a customer is less serious than the short-term benefit of getting product shipped out the door.
Recently, a quality engineer and SPC system administrator I know named Bob admitted to me that control charts and quality data had revealed known problems with a customer’s order. When he informed his management staff of the situation, they instructed him to ship the order anyway. The end of the quarter was up, and Bob knew that the large shipment meant management would exceed sales goals, allowing them to reap a fat quarterly bonus. While acknowledging the shipment’s quality problems, management admitted that “the customer can always send it back if they find problems.”
Needless to say, the quality engineer was furious. “So the SPC system tells us we have problems and we just ignore it? Why are we even using SPC?” In fact, why have a quality system? Good questions, especially considering that there’s no shortage of competitors in Bob’s company’s business space. Making production a priority over quality can put a stake through the heart of any SPC initiative. Just ask Bob. What to do? The answer is obvious to most, and to many managers it’s excruciatingly painful: choose the decision best for the long term rather than the short term
A great example of not making production a priority over quality is demonstrated by a plant manager named George. When quality data intimated that there could be big problems with a shipment, George held a crucial shipment rather than risking shutting down a customer’s equipment with poor quality product. The result? Short-term customer unhappiness coupled with long-term customer loyalty. Additionally, George won the respect of his employees and further emphasized the critical need for high-quality products supported by the use of SPC. Lesson learned…
Okay, we’re almost there! Join me next time for more of this list of Top 10 Mistakes to avoid when using SPC…for numbers 2 and 1: “Using SPC without operations backing” and “Managerial indifference.” ‘Til then.