Hi all,

I've done an internet search and could not come up with a satisfactory answer so I'll post here.

I'm trying to assist my boss in calculating/justifying inspectors. We are using an industry standard of calculating technician:inspector ratios using 10:1 as a baseline. Our facility is at 6:1 currently.

Does anyone have a method of calculating/determining a good inspector to technician ratio? I know that most of the industries have gone to in-process inspections done by the technicians once consistent processes have been established, but I work in the aviation industry and every operation has an inspection step.

Thanks.

I don't think that you should have to follow a standard for this, I don't know that one even exists. You should use whatever fits for your company's situation. My CNC Technicians do thier own in-process inspections, with final done by thier team leader. We have no floor inspectors and it works great for us, we haven't had a issue at the customer in over 3 months.

As usual, I think the answer "it depends". If a high proportion of characteristics can be measured with micrometers and calipers, 10:1 may be great. If the characteristics lend themselves to CMM, roundness measurement machines, or other technical equipment, the ratio of lab techs may be much higher. It is not so much the industry you are in, but the parts you are making that will have the biggest influence.

In a field where inspection is mandated like yours is and you have reached the limit of production level inspection, there is no ratio rule; nor should there be.

Instead of using a ratio, your calculations should focus on resources.

How many inspections
Time required for each one (itemized)
Variation according to work flow (trended and anticipated)
Cost of getting it wrong: slowdowns, poor quality work etc.

This can be communicated on paper and, since it's traceable to verifiable sources, can be enforced.

World class organizations have been pushing towards Quality at the Source, which means building Quality in the product rather than inspecting quality out. Technology, automated inspection devices, and poke yoking are the best methods of Quality at the source, but companies typically don't start there. Most start with removing inspectors and having the operators do their own inspection; thus shifting responsibility for product quality from the Quality department to the operators.

We currently only have one inspector (Certified Weld Inspector) in an organization of 270 people....And we only have that one because it is required by AWS. All other quality personnel in our facility are responsible for maintaining the quality system (IE APQP, PPAP, Calibration, Internal audits, etc). Currently, including myself (Quality Manager), the quality department represents less than 4% of the workforce.

Thanks for all of the replies, but still looking...

We've already headed in the route that Jennifer suggested, but are still being challenged with ratios. Somewhere in time someone started calling a 10:1 production to inspection ratio a baseline. We're challenged with proving that ratiolnale and it's been tough going as our facilities ratios are being compared to another facilities ratios, when our inspection processes and theirs are apples and oranges.

This ratio idea is one you can work with when you have choices in what inspections require this-or-that specific person. I have never heard of a baseline for this because needs for industries vary. In Navy QA, submarine, surface and shore repairs all had different inspector ratios because the needs were different. Manning requirements, if they existed, would have been set at the regional commend level - maybe there is one for your group you can look into.

What choices you may have is left to the amount of time needed to do this-or-that inspection. Steps using chemicals having reaction time (as in NDT dye penetrant testing) may not be controllable, but if one or more inspectors can become more efficient or accurate, you could raise your ratio.

Most start with removing inspectors and having the operators do their own inspection; thus shifting responsibility for product quality from the Quality department to the operators.

I agree, this is becoming more common. It keeps the finger pointing to a minimum, and assumes the operators are the experts of their processes. If the operator is not, they sure should be. But, that still leaves the high tech equipment that usually will require the quality techs. Using this approach would shift the ratio to higher tech to inspector - which just shows how that ratio concept just holds no water at all. It depends - on the investment the company is willing to make in gaging and training. It could be any ratio...:cool: