Put the facts for both occurrences in two columns: the part and characteristic, the defect, the count, where it was found and when it was made. Then list what changed between them. What stayed the same is your first lead. Write a new statement of one or two sentences with no cause and no opinion, and never copy the old statement forward.
Tuesday morning, a small conference table with two folders on it. Left folder: lot 5208, the first complaint. Right folder: lot 6471, this one. You are about to find out whether this is one problem that came back or two problems that look alike.
The difference matters. The same failure means the old investigation was incomplete and you reopen it. A new failure is a separate problem with its own corrective action. Either way, write the problem statement again from the evidence.
Put the facts in two columns
Take each fact from the paperwork, not from memory. The same rows for both:
- The part and the characteristic. Both: BK-6139, hole to hole spacing, 38.00 plus or minus 0.20 mm.
- The defect. Both: spacing over the upper limit of 38.20 mm. The first lot read 38.23 to 38.31. This one reads 38.22 to 38.30.
- The count. First: 9 of 150, which is 6.0 percent. Now: 7 of 120, which is 5.8 percent. The rate barely moved in 11 weeks.
- Where it was found. Both at the customer's assembly station, not by us.
- When it was made. The traveler for each lot shows the pieces came from the end of a long run, the last stretch before the die came out of the press.
Now list what changed
This is the half people skip. The two lots were made on different presses: press 4 the first time, press 2 this time. Different shifts, the second shift then and the first shift now. Different operators. Different coil lots.
That list already damages the old root cause. If the operator was the cause, the defect should have followed one operator or one shift. It did not. The things that did not change are the die, D-3082, and the position in the run. Write those two at the top of the page. They are your first real lead.
Write the new statement
One or two sentences, no cause, no opinion. For this case: "Hole to hole spacing on BK-6139 is over the upper limit on pieces from the end of long runs of die D-3082. Found at the customer on lot 6471, 7 of 120 pieces, and previously on lot 5208." It names the part, the characteristic, the direction, the die, the count and the earlier lot. A reader can check every word of it.
Read more: how to write a problem statement.
The mistake to avoid
Writing the new statement to match the old one. Copying "operator error on the first piece check" forward carries the old guess into the new report. Write from the two sets of facts.
- Pull the paperwork for both occurrences.
- Write what is the same and what changed.
- Rewrite the statement without the old cause.
Open the printable Monday Board
Related on ShopFloorOps
The part, the die, the lots and every number in this book (sensor bracket BK-6139) are a made-up example. The tool sidebars show ShopFloorOps tools, which I make and sell. Every chapter teaches the step itself, so you can use your own forms. New to a term? See the quality glossary.