Technical Library | 2010-06-10 21:01:48.0
This paper researches the effectiveness of the R.O.S.E. cleanliness testing process for dissolving and measuring ionic contaminants from boards soldered with no-clean and lead-free flux technologies.
Technical Library | 2021-10-27 02:20:31.0
The mass flow sensor, or air flow sensor is one of the important sensors of the electronic fuel injection engine. It is installed between the air filter and the intake hose to measure the intake volume of the engine cylinder and adjust the fuel ratio according to it. The mass flow sensor converts the inhaled air flow into electrical signals and sends them to the electronic control unit (ECU). As one of the basic signals to determine the fuel injection, it is a sensor that measures the air flow of the suction engine. So if you want to test it, how should you do? Let's start it.
Technical Library | 2006-11-01 22:37:23.0
Flip Chip Plastic Ball Grid Array (FCPBGA) modules, when subjected to extreme environmental stress testing, may often reveal mechanical and electrical failure mechanisms which may not project to the field application environment. One such test can be the Deep Thermal Cycle (DTC) environmental stress which cycles from -55°C to 125°C. This “hammer” test provides the customer with a level of security for robustness, but does not typically represent conditions which a module is likely to experience during normal handling and operation.
Technical Library | 2017-07-13 16:16:27.0
Controlled humidity and temperature controlled surface insulation resistance (SIR) measurements of flux covered test vehicles, subject to a direct current (D.C.) bias voltage are recognized by a number of global standards organizations as the preferred method to determine if no clean solder paste and wave soldering flux residues are suitable for reliable electronic assemblies. The IPC, Japanese Industry Standard (JIS), Deutsches Institut fur Normung (DIN) and International Electrical Commission (IEC) all have industry reviewed standards using similar variations of this measurement. (...) This study will compare the results from testing two solder pastes using the IPC-J-STD-004B, IPC TM-650 2.6.3.7 surface insulation resistance test, and IPC TM-650 2.3.25 in an attempt to investigate the correlation of ROSE methods as predictors of electronic assembly electrical reliability.
Technical Library | 2017-05-04 17:35:01.0
Most of today's printed circuit board base materials are anisotropic and it is not possible to use a simple method to measure thermal conductivity along the different axis, especially when a good accuracy is expected. Few base material suppliers' datasheet show X, Y and Z thermal conductivities. In most cases, a single value is given, moreover determined with a generic methodology, and not necessarily adapted to the reality of glass-reinforced composites with a strong anisotropy.After reminding of the fundamentals in thermal science, this paper gives an overview of the state-of the art in terms of thermal conductivity measurement on PCB base materials, and some typical values. It finally proposes an innovative method called transient fin method, and associated test sample, to perform reliable and consistent in plane thermal conductivity measurement on anisotropic PCB base materials.
Technical Library | 2014-11-18 23:59:30.0
Performance degradation of packaging material is an important reason for the lifetime reduction of LED. In order to understanding the failure behavior of packaging material, silicone and phosphor were chosen to fabricate LED samples within which an aging test at 125℃ was performed. The result of online luminance measurement showed that LED samples with both silicone and phosphor had the highest luminance decay rate among all test samples because the carbonization of silicone and the consequent outgassing reduced the luminance quickly. The result of the luminance variance with test time was analyzed and an exponential decay model was developed with which the lifetime of LED under high temperature could be estimated.
Technical Library | 2022-01-26 15:22:33.0
Reliability of conformal coatings used to mitigate tin whisker growth depends on their ability to contain tin whiskers. Two key material properties required to assess the reliability of a polyurethane coating are documented experimentally: adhesion strength and puncture strength. A modified blister test using a predefined blister area is employed to assess the adhesion strength and a puncture test is employed to evaluate the puncture strength of the coating. After measuring the properties at time zero, the coatings are subjected to accelerated testing conditions (high temperature/humidity storage and temperature cycling) and the degradations of the coating properties are documented.
Technical Library | 2019-11-12 02:09:22.0
Thermal shock test chamber can be used for testing the chemical change or physical damage on composite materials caused by the thermal expansion and contraction of the sample in the shortest time,which is subjected to extremely and continuous high and low temperature environment.so how to check the temperature recovery time of this chamber? Normally we take following steps to inspect the temepratuire recovering time: 1.Install the temperature sensor at the specified position, and adjust the temperature controller of hot zone and cold zone to the required nominal temperature respectively. 2.The temperature increases and reduces respectively,30min after temperature in two zones reach stable status,record temperature value of the measuring point,pls set the temperature value of two zones to be required nominal temperature. 3.The temperature shock test chamber automatically places the inspected load into theh ot zone,select the corresponding retention time according to regulated standard. 4.Set the transfer time,then the inspection load is transferred from hot zone to cold zone, and the temperature of the measuring point is observed and recorded, and then the reverse conversion of the load from cold zone to hot zone is carried out according to the same method, and the temperature of the measuring point is observed and recorded. www.climatechambers.com
Technical Library | 2018-08-15 17:27:28.0
Smartphones and tablets require very high flexibility and severe bending performance ability of the flexible printed circuits (FPCs) to fit into their thinner and smaller body designs. In these FPCs, the extraordinary highly flexible, treated rolled-annealed (RA) copper foils have recently used instead of regular RA foil and electro deposited foils. It is very important to measure the Young's moduli of these foils predicting the mechanical properties of FPCs such as capabilities of fatigue endurance, folding, and so on. Even though the manufacturers use IPC TM-650 2.4.18.3 test method for measuring Young's modulus of copper foils over many years, where Young's modulus is calculated from the stress–strain (S–S) curve, it is quite difficult to obtain the accurate Young's modulus of metal foils by this test method.
Technical Library | 2015-08-13 15:52:40.0
Pad cratering has become more prevalent with the switch to lead free solders and lead free compatible laminates. This mainly is due to the use of higher reflow temperature, stiffer Pb-free solder alloys, and the more brittle Pb-free compatible laminates. However, pad cratering is difficult to detect by monitoring electric resistance since pad cratering initiates before an electrical failure occurs. Several methods have been developed to evaluate laminate materials' resistance to pad cratering. Pad-solder level tests include ball shear, ball pull and pin pull. The detailed methods for ball shear, ball pull, and pin pull testing are documented in an industry standard IPC-9708. Bansal, et al. proposed to use acoustic emission (AE) sensors to detect pad cratering during four-point bend test. Currently there is an industry-working group working on test guidelines for acoustic emission measurement during mechanical testing.
