Electronics Manufacturing Technical Articles

Soldering Immersion Tin

Apr 10, 2019 | Rick Nichols, Sandra Heinemann

The stimulating impact of the automotive industry has sharpened focus on immersion tin (i-Sn) more than ever before. Immersion tin with its associated attributes, is well placed to fulfill the requirements of such a demanding application. In an environment dominated by reliability, the automotive market not only has very stringent specifications but also demands thorough qualification protocols. Qualification is ultimately a costly exercise. The good news is that i-Sn is already qualified by many tier one OSATs.

The focus of this paper is to generate awareness of the key factors attributed to soldering i-Sn. Immersion tin is not suitable for wire bonding but ultimately suited for multiple soldering applications. The dominant topics of this paper will be IMC formations in relation to reflow cycles and the associated solderability performance. Under contamination free conditions, i-Sn can provide a solderable finish even after multiple reflow cycles. The reflow conditions employed in this paper are typical for lead free soldering environments and the i-Sn thicknesses are approximately 1 μm....

Publisher: Atotech

Symor ESD storage dry cabinet(Working principle)

Apr 08, 2019 | Climatest Symor

Climatest Symor® adopts molecular sieve to dry air, the whole system is controlled by microcomputer, when humidity is high, It will start to absorb moisture,when the humidity reach the pre-set value, it will stop absorbing, and then discharge the water to outside the cabinet by heating,again and again by automatic control. The most effective and environment-friendly moisture-absorbing desiccant is molecular sieve, molecular sieve is the microporous crystal material synthesized by silicon and aluminium oxide. In order to keep the crystal net discharge to be zero, atoms with cations are located in the crystal structure.and the cation used in these synthetic crystals is usually sodium. At present, there are two kinds of molecular sieves widely used in the dry box industry: Class A and Class X. Molecular sieves are synthesized, shaped and activated under strictly controlled production processes. The whole controlled sythesis process can ensure consistency of the three-dimensional pore size. 3A molecular sieve pore size is 3 angstroms, 4A molecular sieve pore size is 4 angstroms; 13X molecular sieve pore size is 8.5 angstroms. The working principle of molecular sieve: Molecular sieves adsorb molecules onto the crystal surface by physical attraction force. Since 95% surface area of the molecular sieve is within aperture,it needs to screen the adjacent molecules by different size. Only small size molecules can enter into the inner adsorption surface of the molecular sieve through the crystal aperture. This selective adsorption phenomenon is called molecular sieve effect. The molecular sieve adsorption capacity and charge density (polarity) are further related to the adsorbed molecules. The molecular sieves can further distinguish which of the mixed molecules can be adsorbed and determine to what extent the charge density can allow the molecules to be adsorbed onto the crystal. Water molecules are particularly small (2.6 angstroms), that belong to highly polar molecules (very strong positive and negative electron density), and are easily adsorbed by molecular sieves, even under very low moisture condition,once the water molecules are adsorbed,they will be firmly fixed on the crystal. The environment-friendly moisture absorption device is equipped with molecular sieve. When it’s absorbing, the memory alloy controller is in tensile state, and the spring is in contractive state,which just make the valve contact the outer baffle, this insulates the outside air from inside dry box air to achieve dehumidification purpose; and after molecular sieve absorbed moisture inside dry box and become saturated, the program will automatically control the memory alloy device to shrink it so that the valve reaches the inner baffle position. Meanwhile, due to the shrinkage of the memory alloy, the spring is stretched and the valve is pulled out of the outer baffle,so that the moisture in molecular sieve will be discharged into the outside. after the dehumidifying process finished, the program automatically control and reset the memory alloy and spring,to restart absorbing status....

Publisher: Symor Instrument Equipment Co.,Ltd

Ingress Protection (IP) test for electronic enclosure test

Apr 07, 2019 | Climatest Symor

Ingress Protection Test Chamber is used to determine the protection degree of product enclosures,the protection level provided by the enclosure is called IP code,our IP test chamber compeletely follow the standard IEC60529 and others. IP protection grade is an important index of electrical equipment safety protection. Protective-grade systems such as ip, which provide a method of classifying products in terms of dust-proof, waterproof and anti-collision levels of electrical equipment and packaging, which have been recognized by most European countries, as drafted by the International Electrotechnical Association (iec (international electro technical commission). And announced in ied529 (bs en 60529 / 1992) outer packing protection grade (ip code). The level of protection is expressed in terms of IP followed by two numbers, which are used to define the level of protection. The first number indicates the extent of the equipment‘s resistance to dust, or the degree to which people are protected from harm in sealed environments. I represents a level that prevents solid foreign matter from entering, with a maximum level of 6; The second number indicates the extent to which the equipment is waterproof. P represents the level of protection against influent and the highest level is 8. Such as the protection level of the motor ip65. Contact electrical equipment protection and external material protection level (first digit) Electrical equipment waterproof protection level (second digit) . IP is the international code used to identify the protection grade ip grade consists of two numbers, the first number for dust, and the second number for waterproof, the larger the number means the better protection level. ...

Publisher: Symor Instrument Equipment Co.,Ltd

How to protect your PCB from moisture related damage?

Apr 07, 2019 | Climatest Symor

How to protect your PCB from moisture related damage? J-STD-033 put forward stricter regulation on the MSD exposure environment,when the exposure time exceed the tolerated,the moisture will penetrate into electronics,Moreover, the newest RoHS regulation will rise soldering temperature,the sudden high temperature will lead to expansion and cracking on electronic components. In order to decrease the moisture defect on PCB for the manufacturers in China,Climatest Symor® begin to concentrated on electronic dry cabinet R&D since early 1990s,we specialize in handling temperature and humidity for 20 years,and we provide best solution for PCB storage....

Publisher: Symor Instrument Equipment Co.,Ltd

Realizing Smart Manufacturing for Electronics

Apr 04, 2019 | Siemens AG

Siemens announced today the introduction of Camstar™ Electronics Suite software, an innovative manufacturing execution system (MES) for electronics. Building on the successful enterprise-level platform for integrated circuit (IC) manufacturing, this powerful, configurable and scalable MES solution enables printed circuit board (PCB) and box assemblers to meet traceability requirements, improve efficiency levels and control manufacturing operations through direct Internet of Things (IoT) connectivity with machines and production lines....

Publisher: Siemens PLM Software

Database Driven Multi Media Work Instructions

Mar 25, 2019 | Tommy Fox

Work instructions are time consuming to generate for engineers, often requiring regeneration from scratch to address very minor changes. They need to be produced in varying levels of detail, with varying guidelines, for multiple stations, operators and lines. Minor component, station or process changes – down to the modification of an individual BOM component – can cause headaches when attempting to maintain consistency across multiple work instructions that are touched by the change.

The solution presented here improves efficiency and saves engineering time by making use of a database driven approach. Manufacturing details, component information, process guidelines, annotations, machine-specific data, and more can be stored in one central database. Any information stored in this single repository can then be modified quickly in one location and automatically propagate seamlessly throughout multiple work instructions. These can be instantly printed out or displayed on screens at appropriately affected stations with the simple click of a button, as opposed to regenerating from scratch, or going in and reviewing many documents to find and update with the change....

Publisher: Optimal Electronics Corporation

Embracing a New Paradigm: Electronic Work Instructions (EWI)

Mar 15, 2019 | Jeffrey Rupert, Travis Loving

While there have been quite dramatic and evident improvements in almost every facet of manufacturing over the last several decades owing to the advent and mass adoption of computer automation and networking, there is one aspect of production that remains stubbornly unaffected. Massive databases track everything from orders, to inventory, to personnel. CAD systems allow for interactive and dynamic 3D rendering and testing, digital troubleshooting, and simulation and analysis prior to mass production. Yet, with all of this computational power and all of this networking capability, one element of production has remained thoroughly and firmly planted in the past. Nearly all manufacturing or assembly procedures are created, deployed, and stored using methodologies derived from a set of assumptions that ceased to be relevant fifty years ago. This set of assumptions, referred to below as the “Paper Paradigm” has been, and continues as the dominant paradigm for manufacturing procedures to this day. It is time for a new paradigm, one that accounts for the vastly different technological landscape of this era, one that provides a simple, efficient interface, deep traceability, and dynamic response to rapidly changing economic forces.

This paper seeks to present an alternative. Instead of enhancing and improving on systems that became irrelevant with the invention of a database, instead of propping up an outdated, outmoded and inefficient system with incremental improvements; rewrite the paradigm. Change the underlying assertions to more accurately reflect our current technological capability. Instead of relying on evolutionary improvements, it is time for a revolution in manufacturing instructions....

Publisher: ScanCAD International, Inc.

An Investigation Into The Durability Of Stencil Coating Technologies

Mar 13, 2019 | Greg Smith, Tony Lentz

It is well documented that Nano coatings on SMT stencils offer many benefits to those assembling PWBs. With reduced standard deviation and improved transfer efficiency nano coatings can provide, there is also a cost. As PWB assemblers work to justify the return on investment, one key question continues to arise. What is the durability or life of these coatings and what can be done in the print process to maximize the life of the coatings?

This paper addresses durability of the coatings in relation to the number of print cycles and underside wipe cycles applied as well as materials used on the underside wipe process. Different parameters will be applied and data will be collected. The results of this study will be summarized to help those using or considering the use of these nano coatings to improve their print process and suggestions will be given to maximize the life of the coatings....

Publisher: FCT ASSEMBLY, INC.

Effect of Encapsulation Materials on Tensile Stress during Thermo-Mechanical Cycling of Pb-Free Solder Joints

Mar 06, 2019 | Maxim Serebreni, Dr. Nathan Blattau, Dr. Gilad Sharon, Dr. Craig Hillman

Electronic assemblies use a large variety of polymer materials with different mechanical and thermal properties to provide protection in harsh usage environments. However, variability in the mechanical properties such as the coefficient of thermal expansion and elastic modulus effects the material selection process by introducing uncertainty to the long term impacts on the reliability of the electronics. Typically, the main reliability issue is solder joint fatigue which accounts for a large amount of failures in electronic components. Therefore, it is necessary to understand the effect of polymer encapsulations (coatings, pottings and underfills) on the solder joints when predicting reliability.

This paper presents the construction and validation of a thermo-mechanical tensile fatigue specimen. The thermal cycling range was matched with potting expansion properties in order to vary the magnitude of tensile stress imposed on solder joints...

Publisher: DfR Solutions (acquired by ANSYS Inc)

Evaluation, Selection and Qualification of Replacement Reworkable Underfill Materials

Feb 27, 2019 | Jeffrey Colish, Luis Lopez, Carlo Viola

A study was performed to investigate, evaluate and qualify new reworkable underfill materials to be used primarily with ball grid arrays (BGAs), Leadless SMT devices, QFNs, connectors and passive devices to improve reliability. The supplier of the sole source, currently used underfill, has indicated they may discontinue its manufacture in the near future. The current underfill material is used on numerous circuit card assemblies (CCAs) at several sites and across multiple programs/business areas. In addition, it is used by several of our contract CCA suppliers.

The study objectives include evaluation of material properties for down select, dispensability and rework evaluation for further down select, accelerated life testing for final selection and qualification; and process development to implement into production and at our CCA suppliers. The paper will describe the approach used, material property test results and general findings relative to process characteristics and rework ability....

Publisher: Northrop Grumman Corporation