Poor Metrology: The Hidden Cost

Michael Cieslinski
Panasonic Factory Solutions Company of America
Buffalo Grove, IL USA

Doing more with less has been the standard operating procedure in manufacturing over the past ten years. Everyone is looking for areas where they can cut corners, maintain quality, and improve productivity. Many placement machines have the ability to self-calibrate and provide capability numbers. In an attempt to save resources, many manufacturers are using these values in place of true capability studies. This practice prompts two questions that need to be answered: "How valid is the internal measurement?" and "If it is not valid, is there still value in using it?"

The simple answer to these questions is that internal calibrations are not valid to predict yield, but do have value for the user. This paper compares and contrasts acquiring a Cpk value from an external metrology system versus one from an internal system. It also provides evidence that an external system is necessary to run a true lean six sigma facility.

An external metrology system provides the capability to truly reduce the cost of poor quality and increase profits. Included case studies show the improvements a user will see in metrics like DPMO and first pass yield when using an external metrology system versus only using an internal calibration system. These studies also show how improving DPMO and first pass yield will actually reduce manufacturing costs.. Increased profitability is what all factories are trying to achieve, but it can be diminished due to potentially misleading reports provided by internal calibration systems. In many companies the cost of this mistake is unknown to management - consequently perpetuating with every new production run.

Capability studies and SPC are key components in running world-class facilities with a low cost of poor quality, but they require good metrology systems. Companies without real metrology can be leaving large savings on the table. In the competitive manufacturing environment, these hidden poor quality costs have to be removed to keep the company viable.

Metrology done correctly can do just that. But past perceptions and lack of knowledge need to be removed as roadblocks to setting up these systems that will save a company money. Over 100 hundred years ago Lord William Thomas Kelvin stated "If you can not measure it, you can not prove it." It could have been more accurately stated "If you can not measure it correctly, you can not prove it." And if you can not prove it, you can not improve it.