Electronics Manufacturing Technical Articles

Controlling Moisture in Printed Circuit Boards

May 01, 2019 | Bhanu Sood, Michael Pecht

Moisture can accelerate various failure mechanisms in printed circuit board assemblies. Moisture can be initially present in the epoxy glass prepreg, absorbed during the wet processes in printed circuit board manufacturing, or diffuse into the printed circuit board during storage. Moisture can reside in the resin, resin/glass interfaces, and micro-cracks or voids due to defects. Higher reflow temperatures associated with lead-free processing increase the vapor pressure, which can lead to higher amounts of moisture uptake compared to eutectic tin-lead reflow processes. In addition to cohesive or adhesive failures within the printed circuit board that lead to cracking and delamination, moisture can also lead to the creation of low impedance paths due to metal migration, interfacial degradation resulting in conductive filament formation, and changes in dimensional stability. Studies have shown that moisture can also reduce the glass-transition temperature and increase the dielectric constant, leading to a reduction in circuit switching speeds and an increase in propagation delay times.

This paper provides an overview of printed circuit board fabrication, followed by a brief discussion of moisture diffusion processes, governing models, and dependent variables. We then present guidelines for printed circuit board handling and storage during various stages of production and fabrication so as to mitigate moisture-induced failures....

Publisher: CALCE Center for Advanced Life Cycle Engineering

Conformal Coating - Sealing PCBs

May 01, 2019 | Scheugenpflug

"Sealing" in dispensing and potting technology describes a process in which sensitive electronics surfaces are coated with a very thin layer of casting resin or protective varnish. It serves to protect against environmental influences and corrosion, resulting in a longer service life and operational reliability of the components. To ensure that the material is distributed homogeneously across the surface, this well-known "conformal coating" process is employed using low-viscosity casting resins....

Publisher: Scheugenpflug Inc.

Adhesive Bonding Instead Of Welding Or Bolting

May 01, 2019 | Scheugenpflug

Adhesive bonding involves the use of adhesive to form a material bond between two or more assembly parts. In addition to regular adhesive bonding applications, hybrid processes, in which the adhesive bond includes another function such as sealing or heat dissipation, are gaining importance. Traditional joining methods such as welding or bolting are progressively being replaced in industrial applications by efficient adhesive bonding processes, since these processes provide a number of advantages such as part weight reduction or simplified parts handling....

Publisher: Scheugenpflug Inc.

Why the minimum order quantity of IC shipping tubes is so high?

Apr 30, 2019 | James tong

Every industry has every unwritten rules, like IC shipping tube moq is high in packaging tube industry rules! This regulation is not to be difficult for customers, but the cost of the problem, as long as the manufacturers feel that even a small amount of packaging tube can do and do too....

Publisher: Shenzhen Sewate Technology Co.,Ltd

The EMS Gateway Model - Local to Global, Seamlessly

Apr 24, 2019 | Brenda Martin

Choosing an outsourced manufacturing partner that is perfect for a new product and close to your design team is quite different to choosing a partner that can manufacture that same product in volume in lower cost locations and fulfill globally. This is where the Gateway model comes into its own. Most large EMS have structured their organizations to leverage proximity to OEM design teams in high cost regions while providing the benefits of low cost regions for volume manufacturing. The "Gateway" facility in higher cost regions provides design engineering, supply chain design, prototype, and NPI services. The goal of the Gateway is to develop an effective build recipe that can then be effectively and seamlessly transferred to one or more volume manufacturing facility that offers lower costs and direct fulfillment to consumers.

We will present a case study that highlights the value of this model and that shows some of the key elements that allow for seamless transitions from plant to plant. The Gateway model is an essential element to a successful global manufacturing model and helps ensure that products are made in the right geography....

Publisher: ZOLLNER ELECTRONICS, INC.

How to store the ic tubes

Apr 23, 2019 | James tong

The ic tubes should be placed in a cool and ventilated place, avoiding direct sunlight........

Publisher: Shenzhen Sewate Technology Co.,Ltd

The working principle of IPX9K Rain Test Chamber

Apr 18, 2019 | Climatest Symor

IPX9K Rain Spray Test Chamber(high Pressure high temperature water jet) simulates the use of pressure washer steam cleaning onto the enclosure, It is recognised as the harshest of all ingress protection tests. However the requirement is becoming more prevalent across many industries. Test method for IPX9K : Make sure the water temperature inside the water tank +80°C, water flow rate with 14L-16L per min, water pressure: 8000 Kpa -10000 Kpa (80–100 bar) at distance of 100mm~ 150mm, The test duration is 30 seconds in each of 4 angles, total spray testing time is 2 minutes. IPX9 rain test chamber applicable standards: IEC 60529 – Degrees of protection provided by enclosures (IP Code).Here is working principle in picture. ...

Publisher: Symor Instrument Equipment Co.,Ltd

Reliability of ENEPIG by Sequential Thermal Cycling and Aging

Apr 17, 2019 | Reza Ghaffarian, Ph.D.

Electroless nickel electroless palladium immersion gold (ENEPIG) surface finish for printed circuit board (PCB) has now become a key surface finish that is used for both tin-lead and lead-free solder assemblies. This paper presents the reliability of land grid array (LGA) component packages with 1156 pads assembled with tin-lead solder onto PCBs with an ENEPIG finish and then subjected to thermal cycling and then isothermal aging....

Publisher: Jet Propulsion Laboratory

What should I pay attention to when purchasing the ic shipping tubes?

Apr 15, 2019 | James tong

The choice of supplier, first of all, is to choose the products offered by suppliers in the market. Since materials that meet certain product functional requirements are not unique, there are many alternatives. There are many factors to consider when purchasing, such as product quality, supply capacity, price, delivery time, reputation, supplier strength, after-sales service and other factors, but specific to the procurement of shipping tubes, we feel the following four points need special attention:...

Publisher: Shenzhen Sewate Technology Co.,Ltd

Noise Fault Detection of High Low Temperature Test Chamber(Climatic chamber)

Apr 11, 2019 | Climatest Symor

With the development of science and technology, the climatic chamber quality has been improved, and the failure rate is reduced, but there still have the failure probability.today we introduce what are the mian factors for big noise high low temperature test chamber: 1.External factors: the bottom angle is uneven, the ground is uneven, adjust the bottom angle, ensure the equipment is in a horizontal position; 2.The equipment is touched other objects or pushed against the wall,pls remove the objects and keep a certain distance from the wall. 3.Compressor noise:check whether the compressor collides with the pipeline,and evaporator dish is loose or not. 4.Check whether compressor shock absorbers are aging and replace them. 5.Solenoid valve noise: solenoid valve reversing caue loud sound, pls add damping glue, if no effect, need to replace solenoid valve. If there is AC noise, need to replace the power board. 6.Check wether the fan or the fan string shaft make noise,whether the fan blades are touched and deformed, whether the fan is fixed or not, pls adjust accordingly or add the rubber pad. If further technical questions,contact us without hesitation!---Climtest Symor® technical team...

Publisher: Symor Instrument Equipment Co.,Ltd