Adhesive Dispensing for Medical Device Assembly Many manufacturers of medical devices, point-of-care and near-patient testing products, and medical wearables are reassessing and upgrading their assembly fluid dispensing capabilities. The medical device and life sciences industry must meet stringent regulations for quality and product consistency, making process control a critical issue. All materials and manufacturing processes—including machining, assembly and packaging—must be documented for complete traceability and process validation. This is critically important with fluid dispensing applications in the assembly of medical devices, point-of-care testing (POCT) and near-patient testing (NPT) products, and other life sciences applications such as medical wearables, which require accurate and consistent deposition of fluid amounts of UV-cure adhesives, cyanoacrylates, silicones, and other fluids in their manufacture. Regardless of the application, the fluids being dispensed and the dispensing technique, in addition to maintaining the quality standards required, the dispensing method must also meet requirements for volume throughput and cost efficiency. Any increase in production volume requirements when relating to assembly is often the key driver that necessitates the move to a more efficient dispensing system. Responding to COVID-19 This is particularly true now as medical product manufacturers worldwide have, over the past two years, increased production of critical supplies and medical devices to address COVID-19 (SARS-CoV-2). Dedicated to helping manufacturers increase production capacity to meet this growing demand, fluid dispensing equipment manufacturers have come forward with precise and safe dispensing solutions to mass-produce ventilators, diagnostic test kits, and other medical devices. One of these fluid dispensing equipment providers is Nordson EFD—a world leader in the engineering and manufacturing of products and systems used for dispensing adhesives, coatings, sealants, biomaterials, and other fluids for the assembly of critical components in medical devices, electronics, and other industries. Responding to requests early on in the COVID-19 pandemic, Nordson EFD supplied multiple automated, robotic fluid dispensing systems to mass-produce a small sub-assembly inside Ventec Life Systems’ unique ventilators. Ventec’s critical-care ventilators are portable, and have provided front-line medical professionals with the systems they need to fight COVID-19. The sub-assembly application required bonding two components together using a UV-cure acrylic. Prior to the pandemic, Ventec was using manual dispensing techniques. COVID-19 forced the company to quickly expand to meet a 180% increase in production volume per month. This was achieved, in part, by utilizing the automated robotic fluid dispensing systems provided by Nordson EFD. Another high-priority COVID-19-related application provided by Nordson EFD involved jetting medical reagents onto diagnostic test strips and bonding the housing of test cards for COVID-19 test kits. Nordson EFD provided proprietary PICO Pµlse® jetting systems for these applications, due to its fast dispensing speed and extremely high precision. These applications are characteristic of manufacturers who needed to scale the sophistication of their fluid-dispensing processes to meet COVID-19 increased-production requirements. In most high-volume manufacturing environments, automated and semi-automated fluid dispensing applications may be in use, dependent on the throughput volume and quality standards required at any stage in the assembly process. Scaling Dispensing Automation Many medical device manufacturers likely started out with manual squeeze bottles and medical syringe dispensing. Then, as production volumes increase, some progress into employing more controlled approaches—with precision benchtop fluid dispensers, pneumatic valve systems, or in-line robotic dispensing systems—for at least part of their fluid dispensing. There are a number of factors that would support adopting a more efficient and controlled dispensing method as a better business solution: a) Shot-to-shot repeatability and accuracy are considerably improved as a more automated and controlled dispensing approach is employed. b) Increased productivity is clearly a benefit that comes with increased automation. For example, the same worker who manually assembles 800 parts during an eight-hour shift can assemble 1,000 to 1,200 parts with the assistance of a pneumatic fluid dispenser. c) Part quality improves when switching from manual squeeze-bottle dispensing to air-powered dispensing, and further along to in-line automated dispensing, because operator-to-operator variance is significantly reduced. The ability to set the time, pressure, and other dispensing parameters for an application improves process control and ensures the right amount of fluid is placed on each part. d) Rework and reject rates lessen when upgrading to more automated dispensing solutions thus improving the yield of the manufacturing lines and greater profitability to the manufacturer. e) The amount of assembly fluid used decreases significantly when using a more controlled method of dispensing. Switching from a rudimentary manual dispensing process, for example, to a pneumatic dispenser can cut the amount of fluid used typically from 50 to 70 percent due to the improved accuracy of the deposit. Medical device manufacturers can greatly benefit by taking a closer look at their production requirements and embracing a more controlled and automated fluid dispensing capability. It is critical, however, to consider each of the five points above, as they represent the actual cost-to-benefit factors influencing fluid dispensing processes. Repeatability, Traceability and Process Control Transforming fluid dispensing from a more manual procedure to a more automated process not only provides cost savings from labor and fluid waste, it more importantly delivers a higher level of consistency, reliability, and traceability in the fluid dispensing process, which is, of course, of the utmost importance in medical device assembly. Repeatability Shot-to-shot repeatability and accuracy are critical factors in fluid dispensing, and with particular importance in the manufacture of medical devices. Depositing the right amount of fluid has a compounding consequence of keeping downstream production moving. If too much fluid is applied, the longer it can take to cure, which will delay production downstream. Conversely, if too little fluid is applied, the part will not properly bond, again interrupting downstream assembly or causing a failure in the product. Precision dispensing systems apply shot-by-shot repeatable amounts of virtually any manufacturing fluid by using digital timers and precision air regulators to determine the amount of material applied. The latest generation of fluid dispensers can distribute practically all assembly fluids—from thin solvents to thick silicones and brazing pastes—with greater accuracy. They deliver exceptional throughput and process control, with consistent deposits from the beginning to the end of the fluid reservoir. For the precise application of adhesives, lubricants, paints, solder pastes, two-part epoxies, UV-cure adhesives, and other assembly fluids, precision dispensing systems enable optimal results. The consistency and repeatability performance of precision dispensing systems goes beyond the actual dispensing equipment itself and is also dependent upon the quality and proper usage of the system components. These consumable plastic components—syringe barrels, adapter assemblies, pistons, caps, and dispense tips—are designed to meet the requirements of different types of fluids and applications, and to dispense the most precise fluid deposit possible. To achieve the highest level of performance from these dispensing systems, several requirements need to be inherent in their manufacture and usage: Each of the consumable plastic components should be designed as part of a complete, integrated system. This will improve yields and reduce costs by producing the most accurate, repeatable fluid deposits possible. Mixing and matching components from different systems or suppliers is a recipe for diminishing performance. The dispensing components should always be used as single-use consumables. In high-precision dispensing systems, barrel IDs (internal diameters) and piston diameters, as well as dispensing tips, are manufactured with tolerances that make any residue from prior dispensing residing in the barrel, piston, or tip degrade dispensing repeatability performance. Once the piston reaches the bottom of the barrel, the barrel, piston, and tip should be discarded. Maintaining precision and shot-to-shot repeatability in dispensing starts with quality manufacturing of the components. For best performance, all components should be certified that no silicone mold-release agents are used in the precision molding process, or at any other time during the production of the dispensing components. Some dispensing solution providers, such as Nordson EFD, also provide a complete dispensing component system molded from medical-grade United States Pharmacopeia (USP) Class VI resin. These syringe barrels, pistons, and end and tip caps are designed to simplify process validation for medical manufacturers. These and even standard dispensing components can be sterilized prior to use in medical device manufacturing. Traceability Most medical device components have a unique barcode assigned to them as they move through the production/assembly process to facilitate keeping track of the components throughout production—a system often utilized by industries other than medical device manufacturing for Six Sigma process controls. https://www.adhesivesmag.com/articles/99899-adhesive-dispensing-for-medical-device-assembly