Technical Library | 2019-12-16 22:20:55.0
When we were children,our parents always warn us "Do comparison shopping before you buy",why they say like this?this is a very simple truth, for the first deal,we are always cautious, through continuous comparison in order to find out the best quality, service, after-sale and price. This apply to any industry,there are many manufacturers of environmental test equipment. When some customers inquire a temeprature humidity test chamber, they will find a very common problem. Why is the price of the same equipment quoted by the two manufacturers very different? 1, the chamber body process,which effects the exterior case quality,this price has a gap. 2, the components, esp.components of the refrigeration system, is the core value of the temperature humidity test chamber. 3, even if the body and refrigeration components are the same, some prices are different, that is the manufacturer technical level. 4, regional issues, Wuxi,Changzhou, Dongguan, these brands need to know more. 5. after-sales, a powerful manufacturer often with a sound after-sales service dept.. The above are both technical and service, as well as the delivery cost of goods to the local and overseas are different.
Technical Library | 2014-10-09 17:51:35.0
Over the last years more and more international newspapers reported in Europe / USA and Japan: "Tunnel train got stuck under the Channel – thousands of people stranded", "Recall of thousands of cars to workshops for control and repair", "Power Failures left households without energy for hours." Very often news like this relate to malfunctions of electric and electronic circuits under adverse conditions or sometimes even in normal operating environment (...) The presentation will deal with all kinds of aspect of cleaning to ensure the reliability of electronic circuitry in ever changing operation conditions in the most important industrial areas.
Technical Library | 2016-11-30 15:53:15.0
The use of microvias in Printed Circuit Boards (PCBs) for military hardware is increasing as technology drives us toward smaller pitches and denser circuitry. Along with the changes in technology, the industry has changed and captive manufacturing lines are few and far between. As PCBs get more complicated, the testing we perform to verify the material was manufactured to our requirements before they are used in an assembly needs to be reviewed to ensure that it is sufficient for the technology and meets industry needs to better screen for long-term reliability. The Interconnect Stress Testing (IST) protocol currently used to identify manufacturing issues in plated through holes, blind, or buried vias are not necessarily sufficient to identify problems with microvias. There is a need to review the current IST protocol to determine if it is adequate for finding bad microvias or if there is a more reliable test that will screen out manufacturing inconsistencies. The objective of this research is to analyze a large population of PCB IST coupons to determine if there is a more effective IST test to find less reliable microvias in electrically passing PCB product and to screen for manufacturing deficiencies. The proposed IST test procedure will be supported with visual inspection of corresponding microvia cross sections and Printed Wiring Assembly (PWA) acceptance test results. The proposed screening will be shown to only slightly affect PCB yield while showing a large benefit to screening before PCBs are used in an assembly.
Technical Library | 2019-05-08 00:04:49.0
It is necessary to know there are some faults that cannot be entirely avoided during the use of temperature and humidity test chamber, but how to deal with them in time is a problem that needs to be paid attention to.Here mainly explain the temperature and humidity test chamber compressor in the reason for the water, and how to deal with it. Reason: water comes from air, because there is always water in the air, known as humidity, which is compressed into supersaturated air and then analyzed to become liquid. The oil comes from the lubrication system of the compressor, possibly because the wear clearance of the mechanism increases, and the lubricating oil will escape into the cylinder. Solution: after the compressor is removed from the temperature and humidity test chamber, with a larger gas storage tank, the oil and water will naturally settle down to the bottom of the jar, and we need to discharge regularly to reduce the oil and water content in the compressed air. Of course, you can also use filters and other things to further reduce the content of oil and water. if you need to know more details about climatic chamber, keep an eye on our website www.climatechambers.com
Technical Library | 2020-03-04 23:53:17.0
Critical to maintaining quality control in high-throughput screening is the need for constant monitoring of liquid-dispensing fidelity. Traditional methods involve operator intervention with gravimetric analysis to monitor the gross accuracy of full plate dispenses, visual verification of contents, or dedicated weigh stations on screening platforms that introduce potential bottlenecks and increase the plate-processing cycle time. We present a unique solution using open-source hardware, software, and 3D printing to automate dispenser accuracy determination by providing real-time dispense weight measurements via a network-connected precision balance. This system uses an Arduino microcontroller to connect a precision balance to a local network. By integrating the precision balance as an Internet of Things (IoT) device, it gains the ability to provide real-time gravimetric summaries of dispensing, generate timely alerts when problems are detected, and capture historical dispensing data for future analysis. All collected data can then be accessed via a web interface for reviewing alerts and dispensing information in real time or remotely for timely intervention of dispense errors. The development of this system also leveraged 3D printing to rapidly prototype sensor brackets, mounting solutions, and component enclosures.
Technical Library | 2023-11-27 18:29:45.0
This paper examines the modeling of viscoplastic solder behavior in the vicinity of interfacial cracking for flip chip semiconductor packages. Of particular interest is the relationship between viscoplastic deformation in the solder bumps and any possible interface cracking between the epoxy underfill layer and the silicon die. A 3-D finite element code, developed specifically for the study of interfacial fracture problems, was modified to study how viscoplastic solder material properties would affect fracture parameters such as strain energy release rate and phase angle for nearby interfacial cracks. Simplified two-layer periodic symmetry models were developed to investigate these interactions. Comparison of flip chip results using different solder material models showed that viscoplastic models yielded lower stress and fracture parameters than time independent elastic-plastic simulations. It was also found that adding second level attachment greatly increases the magnitude of the solder strain and fracture parameters. As expected, the viscoplastic and temperature dependent elastic-plastic results exhibited greater similarity to each other than results based solely on linear elastic properties. !DOI: 10.1115/1.1649242"
Technical Library | 2023-07-16 21:56:12.0
Imagine being able to accurately predict the correct artwork compensations prior to taking on a large quick turn order regardless of the board design, materials, or process. Such predictive power is possible and can be achieved without a lot of cost and complexity. This paper shows how small sets of designed experiments can be used to create a cImagine being able to accurately predict the correct artwork compensations prior to taking on a large quick turn order regardless of the board design, materials, or process. Such predictive power is possible and can be achieved without a lot of cost and complexity. This paper shows how small sets of designed experiments can be used to create a compensation model. Before a discussion of the design of experiments (DOEs), we will examine key processes and material variables that affect movement as demonstrated on real board design layout in a real production process. Only the few most relevant variables need to be included in the experimental design. A solution is presented that uses small experiments that provide the required information for constructing a general compensation model.mpensation model. Before a discussion of the design of experiments (DOEs), we will examine key processes and material variables that affect movement as demonstrated on real board design layout in a real production process. Only the few most relevant variables need to be included in the experimental design. A solution is presented that uses small experiments that provide the required information for constructing a general compensation model.
Technical Library | 2023-04-17 21:17:59.0
The purpose of this paper is to evaluate and compare the effectiveness and sensitivity of different cleanliness verification tests for post soldered printed circuit board assemblies (PCBAs) to provide an understanding of current industry practice for ionic contamination detection limits. Design/methodology/approach – PCBAs were subjected to different flux residue cleaning dwell times and cleanliness levels were verified with resistivity of solvent extract, critical cleanliness control (C3) test, and ion chromatography analyses to provide results capable of differentiating different sensitivity levels for each test. Findings – This study provides an understanding of current industry practice for ionic contamination detection using verification tests with different detection sensitivity levels. Some of the available cleanliness monitoring systems, particularly at critical areas of circuitry that are prone to product failure and residue entrapment, may have been overlooked. Research limitations/implications – Only Sn/Pb, clean type flux residue was evaluated. Thus, the current study was not an all encompassing project that is representative of other chemistry-based flux residues. Practical implications – The paper provides a reference that can be used to determine the most suitable and effective verification test for the detection of ionic contamination on PCBAs. Originality/value – Flux residue-related problems have long existed in the industry. The findings presented in this paper give a basic understanding to PCBA manufacturers when they are trying to choose the most suitable and effective verification test for the detection of ionic contamination on their products. Hence, the negative impact of flux residue on the respective product's long-term reliability and performance can be minimized and monitored effectively.
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