PQ1 (Fig. 1) was located in a preparatory operation for polishing
a component of automobile axles. In this operation, a component
called end yoke, produced in a previous operation, should be
screwed into a clamp, which was part of the tool mounting component
within the polishing machine. In the operation of screwing
it down, there is a need for the end yoke to be slotted into a template,
using holes in its base. All end yokes models can be slotted
onto the same template, without setups. If the holes have not been
made correctly in the previous operation, the end yoke will not fit
onto the template and the screwdriver would not switch on. On the
basis of the template, there was a sensor used to detect the presence
of the holes. At the end of the polishing operation, the end
yoke should be unscrewed from the clamp.