Technical Library | 2023-01-17 17:19:44.0
A test program was developed to evaluate the effectiveness of vacuum reflow processing on solder joint voiding and subsequent thermal cycling performance. Area array package test vehicles were assembled using conventional reflow processing and a solder paste that generated substantial void content in the solder joints. Half of the population of test vehicles then were re-processed (reflowed) using vacuum reflow. Transmission x-ray inspection showed a significant reduction in solder voiding after vacuum processing. The solder attachment reliability of the conventional and vacuum reflowed test vehicles was characterized and compared using two different accelerated thermal cycling profiles. The thermal cycling results are discussed in terms of the general impact of voiding on solder thermal fatigue reliability, results from the open literature, and the evolving industry standards for solder voiding. Recommendations are made for further work based on other void reduction methods and additional reliability studies.
Technical Library | 2019-07-10 23:36:14.0
Pockets of gas, or voids, trapped in the solder interface between discrete power management devices and circuit assemblies are, unfortunately, excellent insulators, or barriers to thermal conductivity. This resistance to heat flow reduces the electrical efficiency of these devices, reducing battery life and expected functional life time of electronic assemblies. There is also a corresponding increase in current density (as the area for current conduction is reduced) that generates additional heat, further leading to performance degradation.
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 | 2019-06-06 13:40:47.0
Legacy electronics assemblies, such as through-hole (Figure 1) and connectorized component packages, are robust and prevalent throughout industry. However, each of these assembly methods have reached their limits in terms of weight, volume, reliability, and most importantly cost. With cost reduction of assemblies now the primary focus area throughout the electronics industry, there is more of a need than ever to implement the latest advancements in surface mount technology (SMT) into electronics assembly designs. Although SMT has been utilized in the electronics industry for many years, implementation of the technology is still in the ever-evolving process of reducing component footprint size, component spacing, and component I/O pitch. Implementation of the most up-to-date SMT processes provides optimal weight, volume, and cost savings, for any type of assembly.
Technical Library | 2019-12-05 13:30:46.0
Conformal coatings are regularly employed to protect the surface of a soldered printed circuit board assembly from moisture, chemicals in the PCBA's service environment, and foreign objects or debris. Conformal coatings are nonconductive and therefore cannot be placed on any location where electrical contact will be required, such as connector pins, test points, and sockets. Conformal coatings are also not permitted on any mechanical interface location, such as mounting holes or brackets, to assure the proper fit between items in the final assembly. In order to apply conformal coatings to an assembly and comply with the restrictions on keep-out areas, masking is employed to protect those surfaces.
Technical Library | 2019-06-04 10:19:46.0
Interconnection technology relies very heavily on the ability of the conductors on a printed wiring assembly to maintain reliable signal integrity. Harsh environmental factors can precipitate a loss of conductivity due to oxidation and corrosion. Connections are typically soldered or inserted using pressure fitted connectors to obtain enough surface contact to meet the electrical conductivity requirements. In pressure contacts, surface integrity is especially critical where the abrasive effects of retraction and insertion can wear off the metallic finish from the contact area. This can expose the underlying copper or nickel and lead to increased resistance at the contact points. These types of conductors are frequently found in card edge connectors where the terminations are plated with a layer of nickel and gold (frequently referred to as gold fingers). A hard gold is typically used containing very small amounts of nickel and cobalt to increase the wear resistance.
Technical Library | 2019-10-21 09:58:50.0
An ACI Technologies customer inquired regarding printed circuit board(PCB) failures that were becoming increasingly prevalent after the SMT (surface mount technology) manufacturing process. The failures were detected by electrical testing, but were undetermined as to the location and specific devices causing the failures. The failures were suspected to be caused predominately in the BGA (ball grid array) devices located on specific sites on this 16 layer construction. Information that was provided on the nature of the failures (i.e., opens or shorts) included high resistance shorts that were occurring in those specified areas. The surface finish was a eutectic HASL (hot air solder leveling) and the solder paste used was a water soluble Sn/Pb(tin/lead).
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 | 2020-04-14 15:49:38.0
The number of through-hole components on printed circuit boards (PCB) has declined significantly over the last decade. Miniaturization in electronics has resulted in less THT (through-hole technology) and leads with a finer pitch. For this reason, the soldering of these components has also changed from wave soldering to Point-to-point selective soldering. Soldering these small, fine-pitch components is a challenge when surface mount components (SMD) are positioned very close to THT components on the PCB layout. This study, done in cooperation with a large automotive EMS customer, defines the process windows for through-hole technology for fine-pitch components. It determines what is feasible to solder and defines layout design parameter that make soldering possible with SMD areas and other components on the assembly.
Technical Library | 2023-11-20 09:56:38.0
Understanding The Crucial Role Of Dust Collectors In PCB Depaneling Machines Precision is paramount in PCB manufacturing, but it must go hand in hand with cleanliness. The intrusion of dust and debris can wreak havoc on delicate electronics. This article explores the pivotal role of dust collectors, their operation, and their necessity for various PCB depaneling machines. The Dust Collector's Crucial Function Dust collectors, also known as dust extractors, play an indispensable role in PCB manufacturing. When a PCB depaneling machine or a Laser PCB Depaneling machine is in operation, it generates a significant amount of dust. The dust collector promptly engages its vacuum motor to suction fine particles off the PCB, directing them to a collector equipped with a filtration system. Which Models Of PCB Depanelers Require Dust Collector? Several PCB depaneling machines necessitate dust collectors to ensure precision and cleanliness, including: I.C.T-5700 Offline Depaneling Machine, high precision, easy manual operation, dual platform, high efficiency. I.C.T-IR350 In-line depaneling machine, high precision, rapid operation, suitable for integration into the SMT production line for Industry 4.0 and AI automated production. I.C.T-LCO350 Laser cutting ensures cutting accuracy of 0.002, ideal for precise cutting requirements. I.C.T-100A Desktop PCB depaneling machine with compact size and high precision, suitable for smaller-scale operations. The Science Behind PCB Dust Collectors To prevent charged dust particles from adhering to PCBs, PCB depaneling machines are equipped with ionizing guns. These devices emit ions that neutralize static charges, making dust particles less likely to stick to freshly cut PCBs. The Vacuum Effect: Suctioning Away Dust During PCB depaneling, a cloud of dust is produced. The dust collector utilizes a robust suction system, often powered by vacuum motors, to draw dust away from the work area. Collected dust is transported to a designated collection point within the dust collector. A Difference In Design: I.C.T-5700 Vs. I.C.T-IR350 The placement of the dust collection apparatus distinguishes PCB depaneling machines. I.C.T-5700 has a bottom-mounted system capturing falling dust, while I.C.T-IR350 features a top-mounted system preventing dust settling on the work surface. This strategic difference ensures efficient removal of dust and debris, guaranteeing a clean and precise manufacturing process. Check: If you want to learn about the comparison of I.C.T-5700 and I.C.T-IR350. The Importance Of Filter Replacement The efficiency of a dust collector relies on its filter, necessitating periodic replacement every 1-3 years, depending on usage frequency. Regular filter maintenance ensures optimal performance. Dust Collectors: Keep Your PCB Manufacturing Clean And Precise Precision in PCB manufacturing is not solely about cutting-edge machinery but also about cleanliness. If you seek a dust collector for your PCB depaneling machine, contact us today to explore your options. Ensure your operations maintain cleanliness, efficiency, and meet the high standards of modern PCB manufacturing. Don't let dust compromise your precision – let's keep it clean together!
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