Technical Library | 2008-02-20 21:42:52.0
Tier 2 and Tier 3 EMS companies face increasing pressure from competition in low-cost manufacturing countries to produce assembled boards at lower cost, with increased complexity and to tighter deadlines. They also face an increasing amount of high-mix, small-to-mediumvolume production runs. Even OEMs find it hard to predict what products they will be manufacturing in three to five years time, driving the need to invest in highly flexible production tools that will cater to their needs over the lifetime of the equipment. This paper examines methodologies for optimising the process, improving stock control and providing greater traceability using lean manufacturing techniques.
Technical Library | 1999-08-27 09:27:10.0
Conformal coating is a material that is applied to electronic products or assemblies to protect them from solvents, moisture, dust or other contaminants that may cause harm. Coating also prevents dendrite growth, which may result in product failure. This paper will discuss the variables that affect the application of conformal coatings, and review in detail those variables that impact the process of selective coating of printed circuit boards.
Technical Library | 2012-11-21 18:57:58.0
The continuing evolution toward advanced miniature packaging has led to ever increasing PCB density and complexity. As the manufacturing process becomes progressively more complicated, there is an ever increasing probability for defects to occur on finished PCB assemblies. For years the Automated Optical Inspection (AOI) industry has relied solely upon two-dimensional (2D) inspection principles to test the quality of workmanship on electronic assemblies. While advancements in conventional 2D optical inspection have made this technology suitable for detecting such defects as missing components, wrong components, proper component orientation, insufficient solder, and solder bridges; there is an inherent limitation in the ability to inspect for co-planarity of ultra-miniature chips, leaded device, BGA and LED packages.
Technical Library | 2019-01-02 21:51:49.0
Failed solder joints remain a constant source of printed circuit board failure. Soldering is the bonding of metallic surfaces via an intermetallic compound (IMC). The interaction between thermal energy delivery, flux chemistry, and solder chemistry creates the solder bond or joint. Today, reliability relies on visual inspection; operator experience and skill, control of influencers e.g. tip geometry, tip temperature, and collection and analysis of process data. Each factor involved with the formation of the solder joint is an element of risk and can affect either throughput or repeatability. Mitigating this risk in hand soldering requires the identification of these factors and a means to address them.
Technical Library | 2019-07-29 10:35:47.0
ACI Technologies can assist its users with process development and experimentation through the use of the conformal coating capabilities in the Demonstration Factory. Four types of coating processes are available at ACI Technologies: dip coating, manual spray coating, programmable spray coating, and manual brush application. (Manual brush application will not be discussed in this article.)
Technical Library | 2020-02-03 17:37:36.0
Accurate impact testing is a key component to establishing that a product is not only reliable, but durable in an end-use environment. ACI Technologies tested a high-g circuit board to demonstrate component durability and ruggedization for guided munitions. The Lansmont Model 23 Shock Test System customized with a Dual Mass Shock Amplifier was used for this testing (Figure 1).
Technical Library | 2019-08-19 09:46:13.0
Boundary scan is a method for testing interconnects on printed circuit boards (PCBs) or sub-blocks inside an integrated circuit. It has rapidly become the technology of choice for building reliable high technology electronic products with a high degree of testability. Due to the low-cost and integrated circuit (IC) level access capabilities of boundary scan, its use has expanded beyond traditional board test applications into product design and service.
Technical Library | 2019-06-17 15:09:43.0
Very often pick and place machines are programmed using CAD data. This data increases the accuracy, precision, and repeatability of its component placement objectives. CAD data makes fine pitch and small component assemblies repeatable, but cannot adjust to a particular board unless it is exactly the same size and shape of the original board used for programming. The process by which printed circuit boards (PCBs) are made only allows some minor changes inboard size and shape, but these small differences are enough for parts to be misplaced. For this reason we use fiducial marks to increase the chances of precise component alignment.
Technical Library | 2019-08-08 10:23:51.0
High mix production is the mainstay of many electronics assembly plants. Lot sizes and board complexities vary and the boards are often mixed technology, comprising a blend of both surface mount and through-hole technology. Modularizing a production line enables a clear distinction between one type of assembly process and another. This article assumes a modern factory where a job can be routed to the selective soldering machine module, the hand assembly bench, or a combination of both. The decision rules of routing a circuit board through hand assembly versus automated selective soldering are discussed. Hand assembly soldering operations require no explanation.
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.