Technical Library | 2023-01-17 17:35:07.0
After years of concentration on resolving productivity- related concerns such as increasing speed, consistency and throughput while reducing costs, many of the world's leading electronics manufacturers have added a new mandate to their agendas. They are seeking to minimize the environmental impacts of their assembly processes and final products without sacrificing the high levels of productivity and quality that have been achieved through decades of effort.
Technical Library | 2023-01-17 18:07:31.0
To achieve higher levels of consistency in PCB output, process engineers are able to maintain tighter controls and reduce process-related defects by using closed-loop process controls. At every stage of assembly, from screen printing through placement to reflow, closed-loop systems help control the variable factors that can have adverse effects on the process.
Technical Library | 2023-01-17 17:12:33.0
Reflowed indium metal has for decades been the standard for solder thermal interface materials (solder TIMs or sTIMs) in most high-performance computing (HPC) TIM1 applications. The IEEE Heterogeneous Integration Thermal roadmap states that new thermal interface materials solutions must provide a path to the successful application of increased total-package die areas up to 100cm2. While GPU architectures are relatively isothermal during usage, CPU hotspots in complex heterogeneously-integrated modules will need to be able to handle heat flux hotspots up to 1000W/cm2 within the next two years. Indium and its alloys are used as reflowed solder thermal interface materials in both CPU and GPU "die to lid/heat spreader" (TIM1) applications. Their high bulk thermal conductivity and proven long-term reliability suit them well for extreme thermomechanical stresses. Voiding is the most important failure mode and has been studied by x-ray. The effects of surface pretreatment, pressure during reflow, solder flux type/fluxless processing, and preform design parameters, such as alloy type, are also examined. The paper includes data on both vacuum and pressure (autoclave) reflow of sTIMs, which is becoming necessary to meet upcoming requirements for ultralow voiding in some instances.
Technical Library | 2013-01-24 20:15:46.0
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Technical Library | 2020-11-09 16:59:53.0
A customer contacted ACI Technologies regarding a high failure rate of their assemblies. They provided assemblies to be X-rayed and inspected for the purpose of identifying any process related issues such as (but not limited to) solder and assembly workmanship and evidence of damage due to moisture related problems during reflow (a.k.a. "popcorning"). Moisture damage usually appears as physical damage to the component. The first indication of moisture damage would be externally observable changes to the package in the form of bulging or fractures to the outer surface of the component, an example of which is shown in Figure 1. Internally observable indicators of moisture damage typically include fractures to the die inside the package and lifted or fractured wire bonds. These conditions would be apparent during transmissive X-ray inspection. Another symptom of moisture related damage would be inconsistent solder joint sizes that result from package deformation during the liquidus phase of the reflow process. None of these indicators of moisture related damage were present on the customer samples.
Technical Library | 2019-05-31 14:19:24.0
ACI Technologies (ACI) characterized the reliability of surface mount RF components. The RF frequency band of interest was the X band (10.7 to 11.7GHz). A two pronged test for reliability of circuit card assemblies (CCA) was designed for both extreme thermal cycling and vibration. The rapid thermal cycling and extreme vibration testing simulates the total stress encountered by the assembly over the life of the product but accomplishes it in a relatively short period of time. In order to perform the reliability testing, a test vehicle consisting of a printed circuit board with test structures and components, was designed, fabricated, and assembled at ACI.
Technical Library | 2020-06-02 15:16:51.0
A commercial systems manufacturer working on a major defense program contacted the Helpline for urgent assistance with an issue of failed parts during reliability testing. They were attempting to incorporate commercial off-the-shelf (COTS) computer-related hardware into a battlefield system and were experiencing reliability issues. It was noted that the parts were labeled by the vendor as "compliant to military (or MIL) standards" but not clearly identified as tin-lead or lead-free. ACI Technologies has supported a number of customers with lead-free issues and we assisted the customer in developing a short term and long-term solution to their problem.
Technical Library | 2019-06-19 11:06:46.0
Tin (Sn) metal displays the characteristic of growing “tin whiskers” from pure tin coatings (most actively on relatively thin, electrodeposited or immersion tin coatings), usually months or years from the initial deposition of the tin. Tin whiskers are electrically conductive, filamentary, single crystals of white (beta phase) tin. These filaments of single crystal tin are usually one to five microns in diameter, and a few microns up to several tens of millimeters long, that grow spontaneously from the tin coatings. Alloying additions of several percent (by weight) of lead (Pb) prevents these electrically conductive tin whiskers from growing. Pb alloyed into the Sn was discovered to prevent the occurrence of tin whiskers in electronic assemblies in the 1950s as the Bell Laboratories solution to the problem of tin whiskers. The alloying of the tin with lead has thus quietly averted incalculable losses from short circuits in electronic equipment for the last 60 years.
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 | 2023-12-06 03:28:49.0
Mastering Precision: I.C.T's SMT Conformal Coating Valves Introduction Of SMT Conformal Coating Valves: In various industries, including electronics, lighting, energy, and life sciences, the SMT conformal coating process plays a critical role. Precision is key, and the choice of a SMT coating valve significantly influences application quality. This article explores I.C.T's SMT conformal coating valves, focusing on the C-0101, C-L101, PJ-01, PJ-01 (with plastic bucket), C-0100, D-0100, D-0300, and the W Series. C-0101 Water Curtain Spray SMT Conformal Coating Valves: The C-0101, a non-atomizing water curtain spray valve, excels with low-viscosity solvent materials. It ensures clean and precise edges in applications like conformal coatings, UV adhesives, backfilling, and volatile substances. C-L101 Rotary Water Curtain Spray Valve: Similar to the C-0101, the C-L101 suits low-viscosity solvent materials, offering a precise edge without splashing for various coatings. PJ-01 Injection Valve (Without Plastic Bucket): Designed for high-precision applications in electronics, lighting, energy, and life sciences, the PJ-01 excels in accurate dispensing and coating. It accommodates various materials, including red glue, liquids, and pastes. PJ-01 Injection Valve (With Plastic Bucket 30CC): The PJ-01, with a 30cc plastic bucket, maintains high precision for complex circuit board applications, offering precise dispensing for materials like red glue, liquids, and pastes. C-0100 Non-Rotating Film Valve: Different from pneumatic atomizing valves, the C-0100 provides precise edge definition without air pressure involvement. It addresses issues related to atomizing drift and fast-drying adhesives, allowing control over the film width. D-0100 Precision Valve: The D-0100, with a unique fluid-sealing structure driven by compressed air, minimizes seal replacement frequency. Suitable for various fluid dispensing, it handles UV adhesives, encapsulating materials, silicones, epoxies, and surface coatings. D-0300 Dispensing Valve: Tailored for precision fluid dispensing at low driving pressure, the D-0300 accommodates a range of materials, including acrylics, silicones, epoxies, and UV adhesives. It's ideal for applications where accuracy and consistency are crucial. W Series: Needle Design Atomization Valves: The W Series offers needle design valves leaving zero residue. Easy to clean without disassembly, they provide adjustable fluid and air pressure for various coating materials, ensuring excellent atomization effects. Analyzing The Options: When selecting a conformal coating valve, consider specific application requirements. C-0101 and C-L101 suit low-viscosity solvent materials, providing clean and precise edges. PJ-01, with or without a plastic bucket, offers high-precision dispensing for complex applications. C-0100 and D-0100 are versatile for various materials, and D-0300 excels in precision dispensing. The W Series offers residue-free needle design atomization valves. Choose based on material, precision, and coating needs. Integration with I.C.T's Conformal Coating Machines: Integral to I.C.T's Conformal Coating machines, these valves enable precise application tailored to specific requirements. Machines like I.C.T-T550, I.C.T-T550U, I.C.T-T600, and I.C.T-T650 come equipped with a range of valve options catering to diverse production line needs. I.C.T SMT Coating Machine.png Conclusion: Selecting the right conformal coating valve is crucial for consistent, high-quality results. Evaluate options based on material, precision, and coating requirements. I.C.T provides tailored solutions for electronic assembly needs. For detailed insights into coating and dispensing machines, follow the provided link. Professional engineers are ready to assist in designing a production line that perfectly matches your requirements, ensuring optimal performance. Contact us for more information and tailored solutions to elevate your conformal coating processes.
