CLEVELAND, OH—November 6, 2018—Pridgeon & Clay, Inc., Grand Rapids, MI, has received the 2018 Link Systems Award for Excellence in Process Control, as part of the Precision Metalforming Association (PMA) Awards of Excellence in Metalforming, for developing a Poka-Yoke process to detect missing or incorrectly installed reinforcement tabs on an automotive heat shield. The process includes automation, pneumatics and different types of sensors to inspect the part, and provides a return on investment within one year.  

Pridgeon & Clay’s recently formed Error Proofing Lab employs two engineers. They are dedicated to providing innovative process improvements, cost reductions and quality enhancements. The lab performed a complete process review for the heat shield and considered alternatives for controlling the process. Visually sorting the parts could lead to human-error issues with a probability of noncompliant parts arriving to the customer. Implementing an inspection system inside the tool would require updates requiring a higher cost than building a Poka-Yoke. The Poka-Yoke incorporates the use of automation, pneumatics and different types of sensors, including proximity, through-beam and vision sensors. 

In practice, once a part is run through the tab-installation die it is placed into the Poka-Yoke by the press operator. The part locates within gauging onto pilots that provide solid orientation. An optical touch button activates the machine and a safety-light-curtain assures the Poka-Yoke is clear of personnel before to starting. 

As the inspection begins, a pneumatic hold-down places pressure onto the part maintaining its position. A proximity sensor confirms the part presence and then a vision sensor collects an image and compares it to a stored image. If the image percentage is correct the part passes the inspection. Next the pilots are pneumatically removed from the part, the hold-down cylinder retracts, and the part is pneumatically shuttled forward down a chute passing a through-beam sensor assuring the proper exit of the part. Parts are batch counted by the PLC. The machine then resets the pilots to load the next part. Inspection takes only a few seconds and once initiated the operator is free to load the next assembly into the die.

Should an inspection fail, the bad part is shuttled left down a chute, passing by a through-beam sensor into a locked box. If the PLC counts five bad parts it notifies the operator of the fault. The press will not operate until a department leader is notified to identify the problem and resets the machine.

To explain the complete Poka-Yoke process, Pridgeon & Clay’s Error Proofing Lab created a training program where personnel were trained to program and troubleshoot the machine. Backup programs are stored on the company’s computer network can be downloaded if sensors are replaced to enable a rapid Poka-Yoke restart. The Poka-Yoke installation and application cost was $20,000. The return on investment (ROI) for this specific part is approximately $25,000 annually, due to elimination of the former sort process. Over the life of the part, ROI is projected to be $105,000. 

The Process Control Award is one of eight Awards of Excellence in Metalforming presented annually by PMA. Sponsored by Link Systems in Nashville, TN, this award promotes the application of electronic-analog closed-loop process controls in the Metalforming process by recognizing innovative electronic solutions implemented by a North American manufacturing company, which have resulted in significant quality, cost reduction and/or productivity improvements.

PMA is the full-service trade association representing the $137-billion Metalforming industry of North America—the industry that creates precision metal products using stamping, fabricating, spinning, slide forming and roll forming technologies, and other value-added processes. Its nearly 800 member companies also include suppliers of equipment, materials and services to the industry. PMA leads innovative member companies toward superior competitiveness and profitability through advocacy, networking, statistics, the PMA Educational Foundation, FABTECH and METALFORM Mexico tradeshows, and Metalforming and 3D Metal Printing magazines.