Enhanced Quality and Manufacturing EvolutionIs Corporate Culture at World Famous A. T. Cross By stepping outside the "box," engineers at the A. T. Cross Company (Lincoln, Rhode Island USA) have transformed a conventional adhesive application method into an innovative new process that has improved throughput and significantly reduced maintenance and adhesive use in the assembly of their world-famous quality writing instruments. At the heart of Cross ball-point pens is the mechanical propel-repel mechanism that exposes the tip for writing and retracts it for storage. Under the previous process, automatic assembly machines incorporated dispensers to apply a dot of adhesive to one part and a dot of activator to a second mating part of the three-piece mechanical assembly. When the three parts were joined together, curing took place and completed the subassembly. Because of the critical nature of the dispensing operation, the assembly machines required significant maintenance and ongoing adjustments to ensure exact deposits. As part of A.T. Cross' Continuous Improvement Program, a team of manufacturing, engineering and tooling specialists was formed and headed up by Ted Seemueller, Tool Engineering manager. The goal was to develop an improved system that could meet their exacting quality standards without costly maintenance. "Our objective," Seemueller recalls, "was to gain complete control of the adhesive application process." Drawing on their collective expertise, they came up with several possible approaches. After evaluating the benefits and trade-offs of each, they arrived at a novel solution. Instead of applying a dot of adhesive to the stationary cylinder, the team proposed to modify the assembly machine so that two of the parts would be rotated as a fine, precise bead of adhesive was applied over exactly 340 degrees of their circumference. The 20-degree gap was the key to preventing overapplication and avoiding any adhesive buildup on the dispensing needle that could affect subsequent assemblies. Activator was similarly applied to a third surface to ensure a quality bond. The remaining challenge was to locate a reliable dispense system that could make the precise bead on rotating cylinders only 0.203" in diameter, and not require high maintenance. As part of their search, the A.T. Cross team contacted EFD Inc. in East Providence, RI. After a meeting to discuss objectives and requirements, EFD application specialists proposed an advanced dispense valve/controller system with pressurized reservoirs for the adhesive and activator. To the Cross team, the features and benefits seemed to solve their design requirements. The special model 752V-UH valve incorporates a flexible diaphragm with an expected life of over 100 million cycles. With very short, adjustable diaphragm travel, the valve provides extremely fine output control. With the diaphragm and fluid chamber made from a unique, ultra high molecular weight irradiated polymer that is inert to most fluids, both precise control and low maintenance were assured. The matching model 7000 valve controller provides microprocessing circuitry to ensure repeat timed output within 0.00005 seconds. In addition, the controller features input/output signals to allow the dispensing system to be interfaced with the assembly machine's computer. Most importantly, by mounting the compact controller near the valve, time setup, adjustment and purge functions can be performed at the point of valve output, simplifying precise dispensing cycle setup. The use of the controller's independent processor avoids the need to re program the host computer when valve output is established or changed. Convinced that the EFD system provided what was needed, Cross ordered twelve valve/controller and tank setups. Tom Mills, A.T. Cross toolmaker, was placed in charge of retrofitting the new systems on the assembly machines. "We put a lot of thought into ergonomics as we designed the valve fixtures," he says, "and incorporated numerous features requested by the production associates who monitor the machines. The time and effort we spent working out the details reinforced the importance A.T. Cross attaches to safe, reliable assembly processes." As production ramped up, the Cross team knew they had succeeded with their new design concept. "Even though we have several different product lines," Seemueller recalls, "when we saw the results of the first dispense systems, we quickly incorporated the new technology into every one of our automated pen bottom assembly machines." According to Tool Engineering supervisor Gary Vario, "The reduction in maintenance allows us much better utilization of our resources. We used to have a skilled toolmaker spending 8 to 10 hours a week adjusting equipment. Now, that time has been reduced to almost zero." He also notes an unexpected benefit--a 50% reduction in adhesive usage attributed to precise deposit control. In addition, the EFD dispense system provides a much higher degree of process control. The microprocessor-based controller allows production associates to make push-button test deposits, which are then weighed on an electronic scale linked directly to the computerized statistical process control system. Seemueller is proud that the team met its objectives, and shares credit for their accomplishment with the EFD specialists who introduced them to the new dispensing technology. "We spent considerable time working out our end of the process," he states, "but without the dispense system to match it, we would not have had a solution." -------------------------------------------------------------------------------- To learn how EFD equipment can help you improve your dispensing processes, please e-mail info@efd-inc.com, or in the USA call our Fluid Application Specialists at 800-556-3484.