Documenting Your Data Collection

About 30 years ago, the concept of data collection for process control took a major leap forward. This was about the time that a combination of electronic technology and economics enabled gaging to become digital. With a digital signal available, it became possible to transfer information via cable directly from a hand tool or digital indicator to the data collector. This made it much more practical to document and monitor the manufacturing process.

These days, checking parts at a gaging station with a hand tool or a dedicated fixture gage connected to a computer via a cable for data collection is the norm. Today's hand tools and digital indicators have built-in data output, making data collection quick, easy, cost effective and reliable. It provides a great solution for many process or quality-control applications.

Now, technology has taken another step forward. Just as cellphones and wireless-computer peripherals have become common, wireless technology is moving onto the shop floor. Small transmitters are now being built into hand tools that enable them to wirelessly transmit data to the gaging computer.

Industry 4.0 aims to take all this data collection to new levels by monitoring everything along the manufacturing process, from collecting and storing individual-measurement data, to offsets sent to the machines, to the production results. Collection of this data needs to be easy and transparent to the operator, with no additional work to delay the process.

However, documenting the part quality sometimes may be more important. For some critical medical, aerospace and military applications, each part’s reading must be documented to verify later that the part was inspected and found to be within specification. Whenever there are life-critical parts, result documentation is likely to be required.

Additionally, all gaging and measuring equipment must be checked periodically to ensure that it is capable of performing the job that it was intended to do, which is to measure parts accurately. For the vast majority of hand tools, this involves verifying the performance of the calipers, micrometers, test indicators and dial indicators. This process of checking performance needs to be done on a regular basis.

The gage documentation process includes the tools for performing the calibration, how and where the process is done, what the performance criteria is, who did it, the standards used and their traceability numbers to ensure the gage is calibrated back to a national standard. Then, the gage is assigned an individual identification (ID) or tracking number. Having a unique individual tracking label on the gage is key. With this and properly filed test results, you will have the historical information required to demonstrate that the gage is "under control" within the calibration process, and you can ensure that test pieces were measured with a traceable gage.

But there could be a missing link to break this chain of documentation.

There is a gage connected to the computer that makes the measurement and sends out the data to be stored for documentation purposes. At best, an operator was asked to key in the identification number of the gage to tie it in with the data for treatability. However, more often than not, the gage ID is not recorded and is just “assumed” to be part of the process of measuring the parts. What happens if the operator plugs in a different micrometer because his battery died or plugged in the wrong gage for the application? There is potential for making measurements with an undocumented gage on critical parts.

The next step to bringing all this data collection to Industry 4.0 is to make each individual gage with its own ID built into the electronics and transmitted as part of the measured data stream. Then, for each measurement, the data-collection software not only knows the measured value but can also store and tie the gage ID directly to the measurement. This would ensure direct data control of the measurements.

Now there is a permanent record of date, time, results and gage ID on file that can be pulled any time in the future. This ensures that the proper gage was used, and it can be linked to the ISO documentation that the gage was certified and under documentation control.