2014: Advent Quality: Left-Handed Widgets

by on December 6, 2014

I am the widget-maker. I make left-handed and right-handed widgets. I want to write a separate procedure for the tasks “make a batch of left-handed widgets” and “make a batch of right-handed widgets”. They are made on the same machine, but the machine requires a different cutting die for each type. My procedure for manufacturing left-handed widgets must include some step of making sure the machine has the correct cutting die in place, otherwise it will be possible to follow the procedure exactly and still make the wrong thing.

I have several choices. I can put a section at the start of the left-handed widget-making SOP that details how to identify the right cutting die, and how to remove and replace the cutting die if necessary. If it’s a simple thing, it might be sensible to do it that way, and train my employees to do that part of the task. Alternatively, I can make “changing the cutting die on the widget-making machine” a separate task with a separate SOP, and that lets me have some employees run the machine and others trained to reconfigure it.

Personally, I would tend towards the second, because the second method means that when I am a busy and successful widget-maker and my widget factory has a dozen machines going at once, and I have two dedicated engineers who maintain and configure my machines, my system is already set up for it. In this approach, instead of assuming the same person will change the die and then make the widgets, I assume that different people will do it, and I write two SOPs, and my SOPs include procedures for handing over the task without losing information or making assumptions. That would probably be of the form “when you are satisfied that the correct die is installed, sign and date the batch production paperwork to say that the machine is correct” and “before you start making widgets, make sure the paperwork has been signed off to say that the machine is correct”.

The important thing is that, however I divide up the tasks, the set of SOPs has to cover the entire process. There should not be any steps that aren’t written down, and there should not be any steps written down that we don’t actually do. If it isn’t important that you walk three times widdershins around the widget-polisher, then the SOP doesn’t include it.

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