Technical Library | 2019-10-07 10:56:06.0
Power interfaces are required when external power sources like solar panels, fuel cells, or batteries are used to generate power for electrical devices. There are two major power interfaces commonly used, direct current to direct current (DC/DC) converters and direct current to alternating current (DC/AC) inverters. While both interfaces are designed to convert from variable DC inputs, they output to different power standards and power levels that are used in different applications.
Technical Library | 1999-08-27 09:24:56.0
Dispensing conductive adhesives in an automated factory environment creates some special challenges. A robust production process starts with understanding the adhesives in their fluid state and which important parameters must be controlled. Developing this understanding requires experience with a large number of materials and valves over time. Common uses of conductive adhesives in surface mount applications, die attach applications, and gasketing are addressed. As vendors of dispensing equipment, the authors see a constant stream of such applications. Dispensing requirements, techniques, and equipment resulting from this experience are discussed. Guidelines for optimizing quality and speed are given.
Technical Library | 2019-05-21 17:20:36.0
Die attach material selection and process implementation play crucial roles in any microelectronic assembly. The chosen attach methods ultimately affect die stress, functionality, thermal management, and reliability of the assembly. Die attach applications are designed to optimize mechanical attachment of the die to the substrate, to create a thermal path from the die to the substrate, and to create an electrical path for a ground plane connection. Some of the more commonly used die attach materials in the microelectronics industry today are epoxies,polyimides, thermoplastics, silicones, solders, and special low outgassing, low stress, anisotropic adhesives.
Technical Library | 2019-06-03 15:32:40.0
ACI Technologies was pleased to assist a customer by conducting elemental analysis on several assemblies displaying severe corrosion. Several board assemblies had failed in the field and exhibited areas of corrosion in close proximity to onboard components. The most common source of corrosion on electronic assemblies is residual flux. Fluxes are specific chemistries applied during the soldering process which improve the wetting of the solder to both the pad and component when forming the solder joint. They can be highly reactive chemicals that, if left on the assemblies, can lead to corrosion, electrical degradation, and decreased reliability. In the presence of moisture and electrical bias, flux residue can enable dendritic growth as a result of electrochemical migration (ECM).
Technical Library | 2020-08-05 17:13:12.0
A primary issue in electronics reliability for military applications is the ability to ensure long term operability in harsh, extreme environments. This requires more rigid standards, such as the MIL-STD-883 (Department of Defense Test Method Standard for Microcircuits), which commercial grade electronics typically do not satisfy. A solution commonly employed is to package the critical electronic components in hermetically sealed metal or ceramic enclosures which are costly and labor intensive. Not only are the components more expensive, but the assembly process is more difficult to automate, resulting in a substantial cost premium for military grade electronics.
Technical Library | 2017-12-07 10:35:50.0
Electronics manufacturers protect their circuit boards with conformal coatings. Conformal coatings serve as a barrier from environmental hazards and internal shorts, tin whiskers, and corrosion at the board level. Within conformal coatings different material chemistries specialize in shielding from an array of hazards and can be applied by multiple methods. The most common method is atomized spray which disperses the material into a fine mist. Alternatively, non-atomized coating controls the materials' dispense shape while maintaining the original liquid form. While some applications demand atomized spray and other scenarios overlap between atomized and non-atomized coating, this paper focuses on the circumstances where materials are ideally suited for non-atomized, selective coating.
Technical Library | 2019-06-12 10:33:58.0
The success of ball grid array (BGA) placement on electronic assemblies is as much a matter of proper preparation and planning, as it is technique. In some designs, it is more appropriate to apply BGAs using a rework station that isolates the placement of the device, without subjecting the entire assembly to thermal reflow. This is especially beneficial in board constructions where the number of BGAs is limited, and the application of the solder paste is difficult, due to small pitch features that stretch the limitation of the stencil construction. Another application for rework stations, involves very large and thermally conductive BGAs, which will not uniformly reflow with other components on the assembly, and may require special process parameters for their proper placement. The most common use of BGA rework stations are for assemblies requiring BGA removal and replacements due to failures in the initial assembly stage.
Technical Library | 2020-03-09 10:50:17.0
A customer called the Helpline seeking advice for cleaning no-clean fluxes prior to applying a conformal coating. The customer's assemblies were manufactured with a no-clean rosin based solder paste (ROL0) and were cleaned with an isopropyl alcohol (IPA) wash. After cleaning, a white residue was sometimes found in areas with high paste concentrations and was interfering with the adhesion of the conformal coating (Figure 1). For conformal coatings to adhere properly, the printed circuit board (PCB) surface must be clean of fluxes and other residues. In addition, ionic contamination left by flux residues can lead to corrosion and dendrite growth, two common causes of electronic opens and shorts. Other residues can lead to unwanted impedance and physical interference with moving parts.
Technical Library | 2012-12-17 22:05:22.0
Package on Package (PoP) has become a relatively common component being used in mobile electronics as it allows for saving space in the board layout due to the 3D package layout. To insure device reliability through drop tests and thermal cycling as well as for protecting proprietary programming of the device either one or both interconnect layers are typically underfilled. When underfill is applied to a PoP, or any component for that matter, there is a requirement that the board layout is such that there is room for an underfill reservoir so that the underfill material does not come in contact with surrounding components. The preferred method to dispensing the underfill material is through a jetting process that minimizes the wet out area of the fluid reservoir compared to traditional needle dispensing. To further minimize the wet out area multiple passes are used so that the material required to underfill the component is not dispensed at once requiring a greater wet out area. Dispensing the underfill material in multiple passes is an effective way to reduce the wet out area and decrease the distance that surrounding components can be placed, however, this comes with a process compromise of additional processing time in the underfill dispenser. The purpose of this paper is to provide insight to the inverse relationship that exists between the wet out area of the underfill reservoir and the production time for the underfill process.
Technical Library | 2023-11-07 09:36:38.0
How to Choose the Right PCB Coating Machine Line Selecting the ideal equipment for your PCB coating line can be a complex task. In this article, we will guide you through the critical components of a standard PCB coating machine line and their solutions to common challenges. We'll delve into the line's composition, including the elevator, transfer station, coating machine, inspection station, curing oven, and their interconnectedness through a return conveyor. Let's explore each element and understand its role. Components of a PCB Coating Machine Line: Elevator: The PCB coating process starts with an elevator, efficiently transporting PCB boards to the next stage. Transfer Station: After the elevator, boards are conveyed to a transfer station, preparing them for the coating process. Coating Machine: The heart of the PCB coating line is the coating machine. We offer a range of coating machines, including I.C.T-T550, I.C.T-T550U, I.C.T-T600, and I.C.T-T650. Inspection Conveyor: Following the coating process, the boards move to an inspection station. The second transfer station is equipped with LED lights and a blue glass cover, enabling operators to closely inspect the coating quality. This feature is vital for ensuring consistent, dust-free coatings. Curing Oven: For UV-curable adhesives, we provide a UV curing oven to effectively solidify the adhesive. Return Conveyor: Beneath the entire line runs a return conveyor, connected to the elevator. This conveyor system efficiently returns PCBs from the last elevator to the first one, reducing manual handling and streamlining operations. The Advantages of the PCB Coating Line Design: 1. Easy Accessibility: The operator's station is strategically located beside the coating machine, ensuring easy access for setup and adjustments. 2. Enhanced Efficiency: The integrated return conveyor eliminates the need for manual transport, optimizing workflow. 3. Quality Control: The inspection station with the blue glass cover enables operators to inspect coatings for quality and cleanliness. 4. Dust Prevention: The blue glass cover also serves as a barrier to prevent dust contamination on freshly coated PCBs. Selecting the right PCB coating machine line is essential for achieving quality and efficiency in your operations. Our meticulously designed equipment line, along with its well-engineered components, can help you attain superior results. If you have further questions or need assistance in choosing the best solution for your specific requirements, please do not hesitate to contact us. We are committed to providing solutions that meet your needs and exceed your expectations.
