Industrial Statistics with Minitab

6.1 Cork

A cava (Spanish champagne) producing company decides to put into operation a plan to reduce the number of defects which occur during the process of bottle labelling.

The external appearance of a bottle is known as ‘presentation’. It comprehends a set of different elements (capsule, collar, ring, label, back label, …) which are fixed up in high speed production lines.

In order to map out an improvement strategy, a plan to collect data was elaborated for each of the company's six different production lines (each line corresponds to a type of cava). The inspection lasted 15 days, during which a daily total of 100 bottles were inspected in each line (in total, 1500 bottles per line). These data can be considered representative of the whole operation process.

The results can be found in file CORK.MTW. Column C1 contains simultaneously the location and the type of the defects. This information is further specified in columns C2 and C3 using the following codes:

Columns C4 to C9 correspond to each of the production lines under study. The purpose is to identify the production line and the type of problem with the highest number of defects and subsequently focus the attention on them.

The corresponding worksheet looks as follows:

To identify the production line with ...