Editor's CommentaryMark: My Word (A monthly column of comments and opinions)
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The results of our recent Top Shops benchmarking survey, which we summarized in our August 2011 issue, provide a useful measure by which any shop can evaluate its own practices and their effectiveness. Top Shops, we found, tend to share characteristics. They typically practice lean manufacturing; favor high speed machining techniques; invest heavily in technology and workforce training; and show consistent profit. In general, Top Shops “have better numbers” than other shops.
One noticeable exception appeared in our study of setup time. The average setup time for the Top Shop group in 2010 was 10.5 hours, compared with 6.5 hours for other shops outside this group, and 7.6 hours for both shops combined. In contrast, the median figures for setup were more like what you’d expect. On this line, Top Shops were shown spending less time than the groups in other columns.
Because the median leaves out very high or low figures, it is less likely to be distorted by these extremes. As we suspected, a closer look at the raw data spotted entries from one company that appeared to be out of line. These figures created a statistical blip that accounts for the seeming anomaly in average setup time. The revised data for setup time can be found here in Table 5 or by clicking the image to the right.
Before we came to this discovery, though, a discussion ensued about exceptional scenarios that might explain why a Top Shop would experience long setup times. For example, a shop engaged in extremely delicate work, such as milling ultra-high-frequency microwave components, might have to count on an unhurried approach to setup. Likewise, a shop that is processing a huge, one-of-a-kind component for a nuclear reactor vessel might have to contend with lengthy setup procedures.
These speculations soon yielded to broader reflections on setup time as a key indicator of overall shop efficiency. The importance of setup and efforts to reduce it bears repeated emphasis. Consider these points:
• Setup is best defined as the time between the last good piece of the current part run and the first good piece of the next run. It’s more than loading and unloading workpieces, and it’s more than fixturing and clamping strategies.
• Reducing setup time is essential to reducing lead times, accommodating small batch sizes and bringing down the levels of work-in-process.
• Reduced setup time is one of the early objectives when implementing lean. When given a zero budget, initial rounds of setup reduction efforts keep the focus on root causes rather than buying quick fixes that only treat symptoms.
• Understanding the cost of setup in terms of lost productivity helps justify targeted investments, such as pallet changers and flexible automation.
• Reducing setup empowers a workforce to concentrate on more rewarding activities.
Today, the focus on setup has to be habitual and persistent. Efforts to reduce setup time must be unrelenting. For any shop, there is no path to the top that bypasses setup reduction.