Technical Library | 2015-04-02 20:12:58.0
The demands on volume delivery and positioning accuracy for solder paste deposits are increasing as the size and complexity of circuits continue to develop in the electronics industry. According to the iNEMI 2013 placement accuracy for these kinds of components will reach 6 sigma placement accuracy in X and Y of 30 um by 2023.This study attempts to understand the dependencies on piezo actuation pulse profile on jetting deposit quality, especially focused on positioning, satellites and shape. The correlation of deposit diameter and positioning deviation as a function of piezo actuation profile shows that positioning error for deposits increase almost monotonically with decreasing droplet volume irrespective of the piezo-actuation profile. The trends for shape and satellite levels are not as clear and demand further study.
Technical Library | 2019-05-21 00:21:26.0
Continue to talk about the dust removal from temperature humidity test chamber. Cleaning and maintenance: 1) Pls remove internal impurities inisde chamber before operation. 2) The power distribution room should be cleaned at least once a year, and the dust can be removed by vacuum cleaner. 3) The exterior chamber must also be cleaned more than once a year, which can be wiped with soapy water. Inspection and maintenance of humidifier: The water storage in humidifier should be replaced once a month to ensure clean water quality, humidifying water tray should be cleaned once a month to ensure smooth flow of water. The inspection of over-temperature protector:during the test: If the temperature is over 20 ℃ ~ 30 ℃ than the maximum value setted,the power supply of the heater will stop, the "OVERHEAT" overt-emperature warning light will automatically turn on but the fan is still in operation, if the equipment runs without operator around,the operator should check the over-temperature protector in advance to ensure wether it has been setted properly before start [wet ball over-temperature protector set to 120 ℃].
Technical Library | 2008-05-14 15:44:58.0
This paper will review some basic past and present flux chemistries that affect flux collection methodology. It will also review some of the most common flux collection methods, self-cleaning techniques, and maintenance goals. And, finally, data will be presented from high volume production testing of an advanced flux management system.
Technical Library | 2017-08-17 12:23:27.0
A novel epoxy flux EF-A was developed with good compatibility with no-clean solder pastes, and imparts high reliability for BGA assembly at a low cost. This compatibility with solder pastes is achieved by a well-engineered miscibility between epoxy and no-clean solder paste flux systems, and is further assured with the introduction of a venting channel. The compatibility enables a single bonding step for BGAs or CSPs, which exhibit high thermal warpage, to form a high-reliability assembly. Requirements in drop test, thermal cycling test (TCT), and SIR are all met by this epoxy flux, EF-A. The high viscosity stability at ambient temperature is another critical element in building a robust and userfriendly epoxy flux system. EF-A can be deposited with dipping, dispensing, and jetting. Its 75°C Tg facilitates good reworkability and minimizes the adverse impact of unfilled underfill material on TCT of BGA assemblies.
Technical Library | 2014-01-02 15:56:55.0
With ROHS compliance the transition to lead-free is inevitable. Several lead-free alloys are available in the market and its reliability has been the main concern. The results from this experimental research aims at making a comparison of different lead-free alloy combinations. Thermal shock and drop tests are a part of this experimental study.
Technical Library | 2013-04-11 15:43:17.0
With the explosion of growth in handheld electronics devices, manufacturers have been forced to look for ways to reinforce their assemblies against the inevitable bumps and drops that their products experience in the field. One method of reinforcement has been the utilization of underfills to "glue" certain SMDs to the PCB. Bumped SMDs attached to the PCB with a no-clean soldering process offer the unavoidable scenario of the underfill coming in contact with a flux residue. This may or may not create a reliability issue... First published in the 2012 IPC APEX EXPO technical conference proceedings
Technical Library | 2016-01-12 11:07:56.0
With the increasing demand of device miniaturization, high speed, more memory, more function, low cost, and more flexibility in device design and manufacturing chain, YINCAE has published a white paper on a first individual solder joint encapsulant which can eliminate underfilling process with at least five times solder joint increase and provide more flexibility for fine pitch and high density application. In order to meet the demand of manufacturing of high speed and low cost, YINCAE has invented a room temperature stable and jettable solder joint encapsulant adhesive – SMT 266. The invention of SMT 266 has allowed our customers to have more flexibility in their high-speed production line such as worry free on the work life of adhesive and workable jetting process.
Technical Library | 2023-02-13 18:56:42.0
This paper describes the results of an intensive whisker formation study on Pb-free assemblies with different levels of cleanliness. Thirteen types of as-received surface-mount and pin-through-hole components were cleaned and intentionally contaminated with solutions containing chloride, sulfate, bromide, and nitrate. Then the parts were assembled on double-sided boards that were also cleaned or intentionally contaminated with three fluxes having different halide contents. The assemblies were subjected to high-temperature/high-humidity testing (85_C/85% RH). Periodic examination found that contamination triggered whisker formation on both exposed tin and solder fillets. Whisker occurrence and parameters depending on the type and level of contamination are discussed. Cross-sections were used to assess the metallurgical aspects of whisker formation and the microstructural changes occurring during corrosion.
Technical Library | 2014-10-23 18:10:10.0
The functional reliability of electronic circuits determines the overall reliability of the product in which the final products are used. Market forces including more functionality in smaller components, no-clean lead-free solder technologies, competitive forces and automated assembly create process challenges. Cleanliness under the bottom terminations must be maintained in harsh environments. Residues under components can attract moisture and lead to leakage currents and the potential for electrochemical migration (...) The purpose of this research study is to evaluate innovative spray and soak methods for removing low residue flux residues and thoroughly rinsing under Bottom Termination and Leadless Components
Technical Library | 2022-08-08 15:06:06.0
Selective soldering has evolved to become a standard production process within the electronics assembly industry, and now accommodates a wide variety of through-hole component formats in numerous applications. Most through-hole components can be easily soldered with the selective soldering process without difficulty however some types of challenging components require additional attention to ensure that optimum quality is maintained. Several high thermal mass components can place demands on the selective soldering process, while the use of specialized solder fixtures, or solder pallets, often places additional thermal demand on the preheating process. Fine-pitch through-hole components and connectors place a different set of demands on the selective soldering process and typically require special attention to lead projection and traverse speed to minimize bridging between adjacent pins. Dual in-line memory module (DIMM) connectors, compact peripheral component interface (cPCI) connectors, coax connectors and other high thermal mass components as well as fine-pitch microconnectors, can present challenges when soldered into backplanes or multilayer printed circuit board assemblies. Adding to this challenge, compact peripheral component interface connectors can present additional solderability issues because of their beryllium copper base metal pins. Key Terms: Selective soldering, drop-jet fluxing, sustained preheating, flux migration, adjacent clearance, lead-to-hole aspect ratio, lead projection, thermal reliefs, gold embrittlement, solderability testing.