Technical Library | 2009-09-18 14:52:06.0
Electronic assembly cleaning processes are becoming increasingly more complex because of global environmental mandates and customer driven product performance requirements. Manufacturing strategies today require process equivalence. That is to say, if a product is made or modified in different locations or processes around the world, the result should be the same. If cleaning is a requirement, will existing electronic assembly cleaning processes meet the challenge? Innovative cleaning fluid and cleaning equipment designs provide improved functionality in both batch and continuous inline cleaning processes. The purpose of this designed experiment is to report optimized cleaning process parameters for removing lead-free flux residues on populated circuit assemblies using innovative cleaning fluid and batch cleaning equipment designs.
Technical Library | 2016-12-22 16:44:04.0
Particulate matter contamination is known to become wet and therefore ionically conductive and corrosive if the humidity in the environment rises above the deliquescence relative humidity (DRH) of the particulate matter. In wet condition, particulate matter can electrically bridge closely spaced features on printed circuit boards (PCBs), leading to their electrical failure. (...) The objective of this paper is to develop and describe a practical, routine means of measuring the DRH of minute quantities of particulate matter (1 mg or less) found on PCBs.
Technical Library | 2019-08-14 22:20:55.0
Cleanliness is a product of design, including component density, standoff height and the cleaning equipment’s ability to deliver the cleaning agent to the source of residue. The presence of manufacturing process soil, such as flux residue, incompletely activated flux, incompletely cured solder masks, debris from handling and processing fixtures, and incomplete removal of cleaning fluids can hinder the functional lifetime of the product. Contaminates trapped under a component are more problematic to failure. Advanced test methods are needed to obtain "objective evidence" for removing flux residues under leadless components.Cleaning process performance is a function of cleaning capacity and defined cleanliness. Cleaning performance can be influenced by the PCB design, cleaning material, cleaning machine, reflow conditions and a wide range of process parameters.This research project is designed to study visual flux residues trapped under the bottom termination of leadless components. This paper will research a non-destructive visual method that can be used to study the cleanability of solder pastes, cleaning material effectiveness for the soil, cleaning machine effectiveness and process parameters needed to render a clean part.
Technical Library | 2019-09-25 04:36:01.0
What is the main function of hot air dry oven? Drying ovens are devices used to remove moisture and other solvents from the items placed inside them through a forced convection process, collecting it elsewhere so that the object becomes dehydrated. A drying oven causes objects to dry out through evaporation. Drying ovens use convection heating,also called air forced, in which the object is heated through air currents. Water from the object escapes into the air, raising the humidity level and causing the semi-solid membranes inside the oven to absorb the water. The end result is that the oven removes water from the object being dried, leaving it dehydrated. Drying ovens contain a system for forcing convection currents to develop, usually either a fan or turbine, which aids in the heating and drying process by ensuring that the hot air circulates,many ovens are equipped with an adjustable ventilation system that allows the user to ensure that the system has an adequate air supply. For details,pls visit our website: https://climatechambers.com/articles&latestnews/what-is-the-main-function-of-hot-air-dry-oven.html
Technical Library | 2013-03-04 16:51:00.0
Chip-scale (or chip-size) packages are rapidly becoming an important element in electronics due to their size, performance, and cost advantages [Hou, 1998]. The Chip Scale Package (CSP) is becoming a key semiconductor package type, particularly for consumer products. Due to their relatively smaller size, new challenges are presented in the rework and repair of CSPs. (...) The specific focus of this paper is the removal process for rework of CSPs and the site scavenging methods required to properly prepare the circuit board for a new component. Process factors such as the heating, fluxing and, atmosphere are discussed.
Technical Library | 2013-10-22 07:38:42.0
In conformal coating many components and printed circuit board locations must remain uncoated due to the insulating nature of the coating. The purpose of the conformal coating masking materials is to prevent migration of the conformal coatings into components that need to clear and designated keep out areas. This applies to both liquid conformal coating and Parylene processing. Get this basic process wrong and it can be a big problem, leading to the next stage of either repairing the conformal coating leak, stripping the conformal coating off the circuit board, removing a component to replace it or scrapping the board. This paper reviews typical masking application methods in conformal coating and provides advice on minimising problems.
Technical Library | 2009-07-09 17:23:07.0
Sometimes you just cannot clean with water. Good examples of this are: circuits with batteries attached, cleaning prior to encapsulation, ionic cleanliness testing, and non-sealed or other water sensitive parts. High impedance or high voltage circuits need to be cleaned of flux residues and other soils to maximize performance and reliability and, in these types of circuits; water can be just as detrimental as fluxes. When solvent cleaning is called for, Hansen solubility parameters can help target the best solvent or solvent blend to remove the residue of interest, and prevent degradation of the assembly being manufactured. In short, using this approach can time, manufacturing cost and reduce product liability.
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 | 2017-12-13 23:58:32.0
In a global market, it is often difficult to determine the best PCB suppliers for your technology needs, while also a chieving the lowest costs for your products. Considering each PCB supplier has their own niche in t erms of equipment, process, and performance, uniform test data from the IPC -9151D Process Capability, Quality, and Relative Reliability (PCQR 2 ) Benchmark Test Standard can help find the right source for the board based on its specific technology requirements. By using a data-based approach to vendor selection, this can remove the subjective nature of sourcing, reduce the need for PCB process experts to map suppliers into technologies, and eliminate irrational sourcing decisions.
Technical Library | 2020-11-29 22:02:49.0
It has been over 25 years since the earliest edition of "Everything You Ever Wanted to Know About Laminates...but Were Afraid to Ask" was pounded out on an old TRaSh-80 Computer. It has undergone periodic review and editing, including adaption for use on our website. (When I entered the industry Al Gore had not yet invented the internet.) Before I "retired" in 2004, we did another minor revision, but it was largely cosmetic, removing most references to the old military specification and introducing IPC-4101, the "new" specification for laminate and prepreg materials.
