Part fingerprinting-based productivity monitoring of CNC machines with low-cost current sensors

Digital transformation of manufacturing industry, Smart Manufacturing, leverages continuous measurement of machines on the shop floor to make effective decisions and improve productivity metrics such as machine uptime and overall equipment efficiency (OEE). However, despite the declining sensor cost, the initial financial and technological skill requirements of digital transformation pose significant barriers for the overwhelming majority (90%) of the manufacturers who are classed as small and medium enterprises (SMEs). To lower this barrier, here we demonstrate an inexpensive (similar to $40 per machine), data-efficient solution that extracts part-level productivity metrics of a CNC machine from its total current consumption alone. We introduce the concept of a part's "fingerprint" and develop a set of methods that allows one to extract the fingerprints and utilize them to monitor each individual manufactured part and their cycle times. Testing on actual production data of over 3 three months in a part-counting task, the algorithms show a good match (96.2% overall accuracy) with manually logged production data is achieved. The presented fingerprint framework is general: it can be extended to multi-sensors, and multi-modal analytics. We expect that such a simple, yet cost-effective, solution will be accessible for a wide range of discrete manufacturers, facilitating the beginning of their digital transformation journey.