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Researching, designing, developing, and manufacturing medical devices is an exact science. Consequently, fluids used to manufacture medical devices must be dispensed according to scientific principles—especially as devices shrink, parts are closer together, and substrates become more fragile and more prone to contamination. To address these challenges, medtech manufacturers are increasingly turning to the use of robotic dispensing technologies.
Used for bonding, gasketing, filling, lubricating, and sealing, the fluids used in medical device applications range from thick to thin. They can be two-part combinations, viscosity changing, or light curable. In addition, they can be dispensed in single or batch processes or in volume manufacturing operations using fully automated in-line systems. Whether they are used for R&D or prototyping purposes or in low-volume or high-volume production, fluids can be dispensed most precisely, reliably, and repeatedly using automated dispensing systems, enabling manufacturers to save materials, time, labor, and resources.
However, the transition from manual to automated fluid dispensing is more involved than simply deciding to automate. Determining what to automate is key. Thus, manufacturers considering the shift to automated dispensing should look closely at their entire process to ascertain whether automating a part of it will help them to improve safety, performance, product quality, reliability, or productivity.
Contact vs. Non-contact Dispensing
Two methods are commonly employed to dispense process fluids: contact dispensing, in which fluids are dispensed using a dispensing tip, and non-contact dispensing, in which fluids are commonly jetted. A manufacturer should choose one or the other depending on the viscosity and consistency of the fluid and the application requirements.
While contact dispensing produces much smaller deposit sizes than non-contact dispensing, the dispensing tip must be placed close enough to the part so that the fluid can make contact with the tip and part at the same time. In automated dispensing processes, this method is more time-consuming than the non-contact method because the tip must be lowered onto the dispensing area and retracted before it is moved to the next dispensing point.
In contrast, non-contact dispensing accelerates the process because the jetting action does not require automation to lower and raise the tip along the z-axis. Thus, the cycling of the jetting valve—which is usually piezoelectric—is performed at much faster speeds and higher cycle rates than tip dispensing can achieve, allowing for greater cycle time savings.
Editor's Note: This article originally appeared in the January 2016 issue of SMT Magazine.
