I love a 6 Sigma project driven by a Hoshin Chart. Hoshin Charts are a very structured method to track key characteristics, drill down the most significant Pareto distributions until you identify a low hanging apple and a potential project. These actions are often called countermeasures, or Root Cause Corrective Actions. In the 70’s & 80’s we called these charts Management by Facts with Results, or MBORs.
This engineer, driven by his Gemba walks and Hoshin Chart, identified labor as the biggest cost not at goal, and took on a project to reduce Mill Labor Costs. The real goal was to keep the labor generation / burden output with less labor, thus lowering the total burden rate at the work center.
The first target was the high volume, top 40 part numbers. The other potential area was set-up time; one operator runs more parts per machine, more parts on the fixture, faster cycle times, and less scrap.
Data was collected, analyzed and discussed. The data suggested that set-up time was a significant item. Further investigation showed that the set-ups were not pre-kitted or pre-pulled. Thus, a lot of set-up time was looking for fixtures, tools, and gauges. The data also suggested an opportunity for improvement within cycle time.
Several of the actions crossed over and helped reduce set-up time, cycle time and scrap. The major actions identified were to standardize tools, always leave five tools in the machine and in same location, and add a hitter. Standard tools allowed for capability studies on these five tools, as well as a reduction of set-up time, inspection, and scrap.
The real winner happened during capability studies. A Design of Experiments (DOE) was run on machine spindle speeds and feed rates. I am not going to tell you the results, but I can tell you on their machine, on 17-4 pre-hardened material, they found a huge opportunity by optimizing at different speeds and feeds than they had been using. Using the now standard tools and re-established speeds and feeds, all the Cpk’s — process capability measures the center tendency — were above 1.33.
The result was a $165,252 annual savings on their 10 mills. The savings resulted from:
1. lower set-up times
2. less inspection times
3. faster production times
4. less scrap
5. lower tooling cost
6. better tool life
7. less walking for the operator to the inspection area
The work reduction time for the operator resulted in another project starting, which often happens. In this instance the new project challenge was to add a washer to the cell and eliminate the next operation (wash).
An excellent project that included a lot of data collection, 3 DOE, 4 major actions, and all by following the Define, Measure, Analyze, Improve and Control (DMAIC) model.