Technical Library | 2021-06-28 20:43:32.0
This book is a compilation of many articles I have published on the subjects of cleaning, reliability, and cleanliness testing. Throughout these articles, I promote a common mantra: Clean is better than dirty. Less contamination is better than more contamination. Some assemblies can tolerate more contamination; others, less.
Technical Library | 2016-08-04 14:33:23.0
Solder paste screen printing is known to be one of the most difficult processes to quality assure in Printed Board Assembly (PBA) manufacturing. An important process step in solder paste screen printing is the under stencil cleaning process and one of the key materials in this process is the cleaning paper1. This, often neglected, material affects the cleaning process and thereby also the print quality. It is therefore important to perform tests of different cleaning papers before one could be chosen. This article describes how cleaning papers can be tested and it also tells how big differences it can be between different materials.
Technical Library | 2013-03-12 13:25:18.0
High density and miniaturized circuit assemblies challenge the solder paste printing process. The use of small components such as 0201, 01005 and μBGA devices require good paste release to prevent solder paste bridging and misalignment. When placing these miniaturized components, taller paste deposits are often required. To improve solder paste deposition, a nano-coating is applied to laser cut stencils to improve transfer efficiency. One concern is the compatibility of the nano-coating with cleaning agents used in understencil wipe and stencil cleaning. The purpose of this research is to test the chemical compatibility of common cleaning agents used in understencil wipe and stencil cleaning processes.Compatibility of Cleaning Agents With Nano-Coated Stencils
Technical Library | 1999-05-07 11:24:21.0
Many manufacturers have now completed the conversion to no clean solder paste. Many factors governed this initial conversion, among those being cosmetics, solder ability, and process ability. In circuit testing or probing through no clean solder paste residues has topically not been a major factor in the conversion decision for several reasons. Due to board design, solder paste was only used on one side of the board and not subjected to testing...
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 | 2019-05-06 23:13:09.0
Temperature and humidity test chamber has brought a lot of help to many industrial enterprises, but while it brings convenience to us, we should also take good care of them, otherwise they may be brought into the end-of-life phase ahead of time. The way of maintenance is also very simple. After daily use, the equipment is cleaned regularly, but the cleaning of the test chamber is also very skillful. If the operation is wrong, it may also lead to equipment failure. Let‘s learn how to extend the service life of the temperature and humidity test box together. 1, Pls clean the working room with water after each use, then dry the interior with dry cotton cloth. 2, Pls regularly remove dust from the evaporator inside the equipment, and periodically wipe the equipment to ensure clean and tidy. 3, When doing the test, the sample should be uniformly placed onto sample shelves,and the vent should not be blocked to prevent the influence of the test 4, It is necessary to pay attention to the cleaning of water tanks in peacetime, after the test or when the equipment is not intended to be used for a long time, all the water in the tank should be discharged, otherwise it will lead to the formation of scale inside the tank. The water used in the temperature and humidity test chamber must be pure or distilled water, or long-term use may result in a humidifier or internal pipe clogging. Above are the usual use notice of temperature and humidity test chamber, if customer adhere to the above several points,it is really able to prolong the service life of the equipment.
Technical Library | 2017-07-27 16:51:57.0
Reliability Expectations of Highly Dense Electronic Assemblies is commonly validated using Ion Chromatography and Surface Insulation Resistance. Surface Insulation Resistance tests resistance drops on both cleaned and non-cleaned circuit assemblies. It is well documented in the literature that SIR detects ionic residue and the potential of this residue to cause leakage currents in the presence of humidity and bias. Residues under leadless components are hard to inspect for and to ensure flux residue is totally removed. The question many assemblers consider is the risk of residues that may still be present under the body of components.
Technical Library | 2019-05-06 23:04:05.0
The temperature and humidity test chamber simulate the temperature and humidity, so there are a lot of things customers shoud notice in the process of use, although there is detailed instruction when purchasing the equipment. But some users just know how the device works and start using it. This is very easy to cause problems in the use of the equipment, so Symor intends to describe the safety details during the use of temperature and humidity chamber. 1. Before the test, determine if the sample contains flammable and explosive substances to avoid combustion or explosion during the test. Of course, also make sure there is no flammable and explosive material around the test equipment, otherwise it may cause fire and other accidents. 2, Do not open the chamber door to operate during the experiment, or the gas in the studio may cause the operator to burn and so on. 3. At the end of the test or at the time of regular cleaning of the test chamber, power off the equipment to avoid electrocution accidents. Also, when cutting off the equipment power, pull the power cord to pull out the plug, otherwise it may lead to a rupture of the power cord and so on. You can contact manufacturers if there are some places you donnot understand, do not dismantle and repair the temperature and humidity test chamber without authorization, otherwise it may lead to more serious problems.
Technical Library | 2016-07-28 17:00:20.0
Packaging trends enable disruptive technologies. The miniaturization of components reduces the distance between conductive paths. Cleanliness of electronic hardware based on the service exposure of electrical equipment and controls can improve the reliability and cost effectiveness of the entire system. Problems resulting from leakage currents and electrochemical migration lead to unintended power disruption and intermittent performance problems due to corrosion issues.Solvent cleaning has a long history of use for cleaning electronic hardware. Limitations with solvent based cleaning agents due to environmental effects and the ability to clean new flux designs commonly used to join miniaturized components has limited the use of solvent cleaning processes for cleaning electronic hardware. To address these limitations, new solvent cleaning agents and processes have been designed to clean highly dense electronic hardware.The research study will evaluate the cleaning and electrical performance using the IPC B-52 Test Vehicle. Lead Free noclean solder paste will be used to join the components to the test vehicle. Ion Chromatography and SIR values will be reported.
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 ℃].
