Innovative Medical Manufacturer Enhances Process Control With Dedicated Dispense Valve Controllers An innovative medical device manufacturer has developed a new product that addresses the number one concern of healthcare workers--accidental "sticks" with contaminated needles. According to a recent study, over one million of these hazardous incidents are reported each year. Sixty-one per cent involve the use of disposable syringes, a situation Retractable Technologies, Inc. (Little Elm, TX) hopes to remedy with their new VanishPointTM. What makes the VanishPointTM unique is that it is the first disposable syringe to feature a needle that automatically retracts after injection, greatly reducing the chance of an accidental needlestick. Helping the company satisfy explosive demand for their revolutionary product are the precision dispensing systems used to make a critical adhesive deposit. Accuracy Is Critical Each stainless steel needle, or cannula, must be bonded to a polypropylene hub with a specific amount of UV-cure adhesive. The ability to regulate, document and repeat the amount of adhesive allowed to flow into the hub's recess is critical, according to production manager Jim Hoover. Underapplication could result in the cannula separating from the hub during injection or retraction. Overapplication must also be avoided, since excess adhesive could build up on the hub. This would prevent the needle from retracting, and defeat the purpose of the new product. Air-powered benchtop dispensers from EFD Inc. (East Providence, RI) had proven accurate and reliable in building the syringes used in the Government-mandated clinical trials, so Retractable Technologies asked them to help design a semiautomated system to meet their expanding production needs. Unlike the benchtop operation, in which the operator applied adhesive to one syringe at a time, the syringe manufacturer now needed a system capable of making ten deposits at once. While output needed to be increased, accuracy and process control had to be maintained. After discussing the new objectives, EFD recommended their Model 740V, an adjustable needle valve designed to make microdeposits of low to medium viscosity fluids. Deposit size, they explained, would be determined by a combination of fluid pressure, flow control setting, tip size and valve open time. A New Way to Improve Process Control To take full advantage of the 740V's precision dispensing capabilities, EFD recommended pairing each valve with a dedicated, microprocessor-based VALVEMATETM 7000 controller. This would ensure the required process control by allowing each valve's dispense time setting to be adjusted in increments as small as 0.001 seconds--without stopping the production line. Realizing the benefits the "one valve/one controller" approach could bring to their dispensing operation, Retractable Technologies designed a semiautomated tabletop assembly machine and had it fabricated by a local machine builder. In the new setup, ten valves are fixtured in a rack, with ten controllers mounted above them. A manifold at the rear of the machine distributes plant air to each valve/controller system, while adhesive is supplied from pressurized tank reservoirs. The individual controllers made valve setup and adjusting the deposit size fast and easy. Once optimal settings were determined for the first system, it was a simple matter to program the remaining nine to produce the same results. Retractable Technologies' new dispensing method has proven to be fast, efficient and, most important, accurate and repeatable. After placing a loaded work holder in position, the operator simply lowers a bar to cycle the valves and make ten identical deposits. Repeatability and More Hoover says the company's decision to go with dedicated controllers has been a tremendous help in maintaining process control. "They make it easy for us to set specific operating parameters for air pressure, fluid pressure and dispense time, but still allow the operator to make minor adjustments within a narrow range of approved settings." "The advantage of this approach," he continues, "is that if something goes amiss and you are operating within the documented parameters, you know you need to look elsewhere to isolate the cause of the problem. It literally forces you to take the proper corrective action." "We needed something that was accurate, repeatable and easily validated," he concludes, "and we found it. We're very pleased with the accuracy of these systems, particularly with their repeatability." "With a lot of equipment, when you shut down at the end of the day and start up again the next morning, it's hard to duplicate the results you got the day before. With the EFD valves and controllers, we never have that problem." -------------------------------------------------------------------------------- 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.