Millions of parts are made each week in modern manufacturing. Most are manufactured on automated production lines with a minimum of human interaction. Every piece of equipment in the production line has been set up to produce a specific component that is created to exact standards within a certain error tolerance. Even the most complex and expensive machinery can shift or lose alignment over time. Even though these changes are minimal in size, they can have a big impact when the machines are making important parts for the aviation or auto sectors. This is where metrology systems and services enter the picture.
Importance of Metrology
From the conception of an item until the point at which it is ready for use, metrology offers the concepts and language that integrate multiple steps in its design, manufacturing, and performance. Metrology is the decision-making foundation for managing creation, production, and function. With the help of metrology, companies can manufacture goods quickly, more precisely, and to better standards. These advantages are passed on to customers as products become less expensive and of higher quality.
Role of Metrology in Process Validation
Validation of the manufacturing process is an essential step. This stage involves checking the production process, including the equipment, and if it was installed and calibrated appropriately. The next step is to confirm that the product has satisfied its specifications and is ready to be constructed. Depending on particular requirements, the following metrology systems and services may be required at this level:
Initial Sample Inspection Report
This inspection is multi-dimensional. Measuring all dimensions takes time, which is why it is carried out on just a handful of parts (for example, 1 part per cavity in a 2-cavity mold). Unless there is any major modification to the production setup or process at a later stage, this is usually the only time when all dimensions are measured. The manufacturing process is now tracked using a much smaller number of dimensions.
A critical dimension is one that is vital to the function of a product. A control dimension is a dimension that can be used to determine whether the manufacturing process is under control. This sort of dimensional measurement is carried out on a greater number of samples (for example, 30 samples per cavity per process setting) but on a significantly lesser amount of dimensions (often about five dimensions). The manufacturing process’s control over the data is then evaluated statistically to see if it will ultimately stay within its specified limits over time.
Critical/Control Dimension Measurement Systems
Apart from evaluating the Critical/Control Dimensions during validation, the measurement system can be designed to be used during manufacturing. Then, anytime it may be necessary, this system can be used for measuring parts. For this type of measurement system, a high-quality Metrology fixture is required. At the very least, this fixture should be able to consistently hold parts spanning from the lower to higher specification limits. The completed measurement system would be put through a Gauge R&R (Gauge Repeatability and Reproducibility) as part of an MSA (Measurement System Analysis). When it comes to that dimension’s tolerance, a Gauge R&R will show whether a measurement system is right for measuring that dimension.
In short, modern manufacturing processes rely on metrology for quality assurance. Production lines can churn out hundreds of identical pieces of high-tech machinery with metrology systems and services. Mass production would not exist without standardized components, and the world would look quite different from what it is today!