SCOTTSDALE, Ariz — Cox Instruments, a supplier of precision flow measurement instrumentation, has established a world-class flowmeter production line compliant with the ISO/TS-16949 automotive industry standard. Cox Instruments’ manufacturing process implements a comprehensive quality documentation system addressing every process required to economically produce the highest quality flow measurement products.
The ISO/TS-16949 Standard is an International Standardization Organization (ISO) Technical Specification defining the quality system requirements for the design/development, production, installation and servicing of automotive-related products. Developed in conjunction with the International Automotive Task Force (IATF), ISO/TS-16949 aligns into one global specification all existing standards used in the automotive industry supply chain. This includes QS-9000 (United States), VDA6.1 (Germany), EAQF (France) and AVSQ (Italy).
According to Ron Madison, vice president, sales and marketing, Cox Instruments has instituted a unique “Company within a Company” approach integrating its flow measurement expertise with its flowmeter manufacturing capabilities. Cox’s production operation employs automated flowmeter assembly, calibration, testing and data management, as well as automated material management and invoicing in a single-piece flow work cell with point-of-use stock.
For its advanced production operation, COX Instruments designed and fabricated an automated primary standard flow calibrator with an automatic clamping fixture. The flow rate is automatically stepped through the entire range of the flowmeter while collecting the calibration data and developing a cal report.
Error-proofing of the production line was achieved by using a series of assembly fixtures, which perform sensor tracking of each part. Optical sensors detect the parts and monitor/record the operation. Programmable logic controllers (PLCs) and a management computer monitor every process step, while providing evidence that no process is omitted. With this approach, a flowmeter cannot continue to be processed once an improper assembly task has occurred, nor can it bypass a station. Material traceability, assembly control parameters, calibration and test data are automatically recorded and stored with each flowmeter serial number, providing a comprehensive quality record.
Implementation of ISO/TS-16949 focuses Cox Instruments’ flowmeter manufacturing operation on advanced product quality planning (APQP) procedures, including the Production Part Approval Process (PPAP), Process Failure Modes Effects Analysis (PFMEA) and Design Failure Mode Effects Analysis (DFMEA). The APQP process prevents errors in all aspects of the design and manufacturing process and is synonymous with Six Sigma quality standards.
PPAP outlines methods used for approval of production and service commodities, including bulk materials, up to and including part submission warrant in the Advanced Quality Planning process. The purpose of the PPAP is to ensure that component suppliers comply with the design specification and can run consistently without affecting the production line while improving quality systems. The PPAP also ensures that suppliers will achieve first-time quality and reduce the cost of quality.
PFMEA is a systemized group of activities intended to: (a) recognize and evaluate the potential failure of a product/process and its effect, (b) identify actions which could eliminate or reduce the occurrence, (c) document the process, and (d) track changes to processes to avoid potential failures. This process informs manufacturers of potential failure modes and their effects in advance. PFMEA identifies critical process variables for each component, sub-assembly and assembly. A control plan is defined for each critical variable ensuring the variable is maintained within control limits.
DFMEA applies the Failure Mode and Effects Analysis method to help manufacturers investigate ways that a product design might fail in real-world use. DFMEA documents the key functions of a design, the primary potential failure modes relative to each function and the potential causes of each failure mode. It allows the cross-functional design team to document what they know and suspect about a product's failure modes prior to completing the design, and then use this information to design out or mitigate the causes of failure. In addition, DFMEA is the foundation for design verification and validation.