Tim Chambers

Here we talk a lot about the two different styles of poke yoke – I don’t know whether there are official terms for them, the indicators – colour coding, shadow boards, tick boxes, and the physically preventative – jigs, pins, barriers etc. Obviously the ‘harder’ solution being physically preventative.
With this X ray idea, surely we should/could…[Read more]

Here we talk a lot about the two different styles of poke yoke – I don’t know whether there are official terms for them, the indicators – colour coding, shadow boards, tick boxes, and the physically preventative – jigs, pins, barriers etc. Obviously the ‘harder’ solution being physically preventative.
With this X ray idea, surely we should/could…[Read more]

To be honest – I much prefer the use of Cp & Cpk terms (in conjunction) to describe a process in relation to it’s specification, a completely unambigous method (as long as everyone uses 3 deviations).
I don’t like negative sigma, I prefer conversion of  %good (to sepc limits) to sigma level; using +NORSINV() in Excel for example.

I don’t agree you can have negative sigma, I don’t agree you can have negative Cp, I do agree you can have negative Cpk.
I think this is all driven by how you calculate sigma levels, if calculated from simple 3 x Cpk values, it is obvious how negatives have been generated (i.e. process average outside spec. limits). If generated from absolute…[Read more]