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 17:22:28.0
The impact of voiding on the solder joint integrity of ball grid arrays (BGAs)/chip scale packages (CSPs) can be a topic of lengthy and energetic discussion. Detailed industry investigations have shown that voids have little effect on solder joint integrity unless they fall into specific location/geometry configurations. These investigations have focused on thermal cycle testing at 0°C-100°C, which is typically used to evaluate commercial electronic products. This paper documents an investigation to determine the impact of voids in BGA and CSP components using thermal cycle testing (-55°C to +125°C) in accordance with the IPC- 9701 specification for tin/lead solder alloys. This temperature range is more typical of military and other high performance product use environments. A proposed BGA void requirement revision for the IPC-JSTD-001 specification will be extracted from the results analysis.
Technical Library | 2019-06-20 07:45:19.0
One of the two basic risks of employing the commercially accepted, Restriction of Hazardous Substances (RoHS) compliant, lead-free (Pb-free) electronics is the threat to the electronics reliability from the growth of tin whiskers. The other basic risk deals with Pb-free solder joint reliability.
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 | 2020-07-01 19:45:04.0
A company approached ACI Technologies (ACI) for assistance with a new product that was about to undergo its initial proof-of-concept prototype build. This product was an item that was being furnished to the Department of Defense for a program designed to increase the technical capabilities of computer equipment issued to the war fighter. The requirements for this item specified the use of tin-lead solder during assembly of production units. One of the main responsibilities for ACI during this project was to assist the client in mitigating the risk introduced using commercial off-the-shelf materials that may be lead-free.
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 | 2024-02-26 09:08:23.0
Precision Control in Electronic Assembly: Selective Wave Soldering Machine Discover the technical features of I.C.T's Selective Wave Soldering Machines, including precision flux application and innovative preheating systems. Learn how these machines redefine efficiency and reliability in electronic assembly. Introduction: Enhancing Precision Soldering: Technical Features of Selective Wave Soldering Machines by I.C.T Explore the innovative design and operation of I.C.T's Selective Wave Soldering Machines, featuring a seamless PCB handling system and modular design for enhanced assembly line flexibility. Experience precision control and efficiency with comprehensive PC controls, allowing easy adjustment of solder parameters like temperature and flux type. Automatic calibration and CCD mark positioning ensure consistent soldering quality. Detail Excellence: Enhancing Selective Wave Soldering Technology Flux System Mastery German high-frequency pulse injection valve ensures precise flux application. Optional flux nozzle jam detection simplifies maintenance. Pressure tank and precision pressure flow meter ensure consistent flux control. Preheat System Excellence Bottom IR preheating system ensures stability and efficiency. Maintenance is simplified with a tool-free mode and plug-in design. Soldering System Innovation Swedish "PRECIMETER" electromagnetic pump coil ensures stability. Stainless steel soldering pot prevents tin liquid leakage. N2 online heating system reduces solder dross. Transmission System Mastery Specially designed material profiles ensure operational stability. Thickened customized rails guarantee flawless operation. Control and Intelligence Keyence PLC+module high-end bus control system ensures stability. Industry 4.0 compliance allows guided programming and real-time data visualization. Market Promotion and Success Stories: Elevating Selective Wave Soldering Machine I.C.T's strategic market positioning has led to global success across diverse industries. Success stories from European clients highlight reliability and trust in the machine. Over 70 units sold across 20+ countries since 2022, establishing its industry-leading position. Conclusion Conclusion: I.C.T's Selective Wave Soldering Machine combines technical excellence with global market success, solidifying its leadership in precision soldering technology.
Technical Library | 2007-08-16 13:34:31.0
While experienced inspectors may be able to determine the aesthetic differences between a lead-free PCB assembly and a tin-lead version, one cannot rely on the "experienced eye". "Less wetting out to the pad edges" (Figure A) and "graininess and lack of shininess of the solder joint" (Figure B) are typical comments about some lead-free solder joints. However, in cases where a Nitrogen atmosphere was present during the reflow of the solder joint (Figure C), there will be little visual differences between the lead free alloys and their tin-lead counterparts.
Technical Library | 2017-10-12 15:45:25.0
The risk associated with whisker growth from pure tin solderable terminations is fully mitigated when all of the pure tin is dissolved into tin-lead solder during SMT reflow. In order to take full advantage of this phenomenon, it is necessary to understand the conditions under which such coverage can be assured. A round robin study has been performed by IPC Task group 8-81f, during which identical sets of test vehicles were assembled at multiple locations, in accordance with IPC J-STD-001, Class 3. All of the test vehicles were analyzed to determine the extent of complete tin dissolution on a variety of component types. Results of this study are presented together with relevant conclusions and recommendations to guide high reliability end-users on the applicability and limitations of this mitigation strategy.
Technical Library | 2014-06-23 14:50:52.0
It was unusual to see chip terminations change colors when tin lead solders were used but with the introduction of lead free reflow soldering and the corresponding increases in reflow temperatures terminations are now changing colors. Two conditions are present when reflow temperatures are increased for lead free solder alloys that leads to discoloration. Reflow temperatures are above the melting point of tin (Sn MP is 232oC). Air temperatures commonly used in forced convection reflow systems are high enough to both melt the tin plating on the termination allowing it to be pulled into the solder joint due to solder joint liquid solder surface tension leaving behind the exposed nickel barrier. Now those metal oxide colors will be visible due to high air temperatures during reflow.
