Issue link: https://iconnect007.uberflip.com/i/1000349
JULY 2018 I SMT007 MAGAZINE 37 employing semi-automatic or fully automatic options during the early design development stage. Further complicating the selection process are the number of different assembly methods, which include: 1. Deformation methods based on press fit, heat staking, swaging, molded-in snap latches and retention features designed into mating parts 2. Mechanical fastening methods, encom- passing the use of screws, bolts, rivets, pins, retention rings, springs or clips 3. Welding parts using ultrasonic, radio or high frequency, laser and spin tools 4. Soldering mechanical or electronics parts on a PCB 5. Bonding parts using pressure sensitive adhesives, epoxies, cyanoacrylates, poly- urethanes or solvent cement materials. Bonding may also span employ processes, such a dispensing, curing, laminating, molding, coating and so on 6. Marking parts for component or assem- bly tracking, while not expressly involving assembly, may still eliminate, streamline or influence assembly processes. Marking encompasses surface treatments through flame, corona, plasma, solvent or ultra- sonic washing, and may apply tools such as lasers, ink jet, bar coding, pin coding or adhesive labels 7. Testability or access to inline testing should be considered during design phase, testability should be considered to ensure that, at a certain assembly stage, the device has access points to test for pass/ fail prior to proceeding to next station The long list above still leaves open the question of whether the assembly method chosen should apply a manual or automated process. Manual assembly is best suited for high-complexity, low-volume assembly. Ideally, a complex assembly should be broken down into incremental assembly steps that can be handled by fixturing or automation to ensure manual assembly does not cause fatigue or errors. Automated and semi-automated processes are better suited for assembly applications demanding consistent repeatability, confor- mance to strict time requirements, or produc- tion volumes over a million devices per year. Flexible automation solutions based on a common standard platform where fixtures and tools can be reconfigured and adapted are favored for products that are customized for different markets or that go through frequent product refresh cycles. Additional automation benefits include reduced risk, scrap, errors and assembly time, as well as reduced operator hazard and fatigue. Automation also allows for data collection and analytics that help isolate issues more efficiently and resolved them more quickly to minimize downtown. The goal of DFA is to ensure the right decisions are made Figure 3: While traditional assembly techniques continue to dominate medical device assembly today, the emer- gence of additive manufacturing and printed electronics are helping manufacturers to deliver highly engineered and integrated products.