PCB + ASSEMBLY Flawless
PCB + ASSEMBLY Flawless immersion tin plating layer after reflow soldering. Source: Atotech Self-dewetted immersion tin plating layers after reflow soldering. Source: Atotech Resolution example of Elpemer edition 766. Source: Peter Roskothen Reference is made to the REACH regulation (EC) No. 1907/2006. According to the information provided by the Federal Institute for Occupational Safety and Health (REACH CLP Biocide Helpdesk), the “dry“ ink layer has to be regarded as a component of the product i.e. of the printed circuit board. Thus, the reference of the candidate substance is not the ink layer itself, but the total weight of the PCB comprising the ink. If the mass percentage of the candidate substance to the PCB is < 0.1, there is no duty to notify this information. When a candidate substance liable to notification is formulated with a mass percentage of > 0.1, the REACH regulation does not specify how the notification has to be passed; a respective notification can be provided either with the documents supplied, or by the labelling of the product. At the first glance, this seems to be good news, since labelling will not be required in most cases. However, one has to consider the substantial accumulation during the assembly process (condensate trap), and thus the “exporting” and exacerbating of the problem from PCB fabrication to assembly production. Proven photoinitiators solutions It is possible to dispense with the two photoinitiators mentioned above, in particular with photoinitiator 907, without suffering any loss in performance. Shortly after the announcement of the new classification, Peters developed solder resists free from the photoinitiators 907 and 369. For several years now, such Elpemer solder resists made by the company have been available, which are also Zusammenfassung Aufgrund der aktuellen SVHC-Situation sind nicht nur Leiterplattenhersteller, sondern auch Elektronikhersteller und EMS-Firmen hinsichtlich der Inhaltsstoffe der von ihnen verwendeten Produkte sensibilisiert. Praxiserprobte Lötstopplacke ohne kritische Foto - initiatoren sind verfügbar. Résumé En raison de la situation actuelle des SVHC, les fabricants de PCB, d‘électronique ainsi que les entreprises d’EMS ont tous été sensibilisés aux substances contenues dans leurs produits. Des résistances de soudure sans photo-initiateurs essentiels, qui on était éprouvées sur le terrain, sont disponibles. Резюме В связи с текущей ситуацией с SVHC было привлечено внимание производителей электроники и компаний EMS к их составам продуктов, а также к использованию защитного резиста (СПОТ маска) без фотоинициатора. suitable for direct imaging with LED or laser light sources. Many PCB manufacturers have successfully introduced these products. Since ECHA has now included the photoinitiator 907 in the SVHC candidate list, the discussion about substitutes has been revived. This way, the early development of alternative products pays off now, on which ample practical experience has been gained in the meantime. Even the new solder resists free from these photoinitiators reach reproduction accuracies of up to 50 μm. For Peters, it has been important that by their Elpemer 733 edition, a product series for the classical contact exposure, and by edition 766, a product series for direct imaging have been developed which are both free from the photoinitiators 907 and 369, with all common coating methods being covered. Amongst others, the Elpemer editions 733 and 766 fulfil today’s demanding requirements of the automotive field, reaching excellent insulation results under moisture even after a permanent storage at a temperature of 175 °C. What is more, they show a high degree of elasticity and adhesion without cracking after temperature shock tests. The Elpemer editions 733 and 766 stand for • high permanent temperature resistance and temperature shock resistance of up to 175 °C, • temperature-critical high current applications, • an excellent surface insulation resistance (SIR) at 1000 V, and • finest structures thanks to direct imaging and contact exposure. Moreover, photoimageable solder resists variants are available in special colours such as red, blue, black or temperature-stable white, also free from the photoinitiator type 907. Conclusion Owing to the current SVHC situation, both electronics manufacturers and EMS companies have been sensitised to this situation, as far as the content of their products is concerned. PCB manufacturers who were early in changing over to type 907-free solder resists do not have to worry, thanks to Elpemer, and can respond with ease to a growing number of SVHC related questions. www.peters.de Special colours are also free from the photoinitiator 907. Source: Peter Roskothen
PRODUCT UPDATES PCB + ASSEMBLY Solder fume filter for healthy work environment In corona-times, all topics around the health of employees are receiving higher attention – and that´s a good thing because staff members remain the most important asset. The media reported research from the Technical University Berlin addressed the spreading of aerosols in closed room environments including the risk of infection. Technical ventilation minimizes the risks of infection. Wearing a mask in a hand soldering work environment is uncomfortable. Additionally, face masks are limited to reduce the spread of fine aerosols created while a person is just speaking or breathing. In closed room environments, technical ventilation is needed to have sufficient air exchange rates. Fresh air is “thinning” the potentially virus charged aerosols and thus reduces the immediate danger of infection. Filter units to clean the process air also fit into the concept of freshening the air! Es- The fume extraction units Easy Arm 1 and Easy Arm 2 supply a three-stage filter system to clean the process air. This creates a healthy work environment and operators are protected against illnesses. Source: Ersa pecially in a soldering environment, the highly efficient filter systems capture the air in the operators’ direct work area. They filter out harmful particles generated from flux in the solder smoke. In combination with technical aeration, the indoor climate is improved. Solder fume extraction units protect from respirable particles (< 1 micrometer) contained in solder smoke. Thereby, they have a preventative effect against the pollution of human respiratory tracts and chronic diseases like asthma and bronchitis. The Ersa fume extraction units Easy Arm 1 and Easy Arm 2 supply a three-stage filter system to clean the process air. The pre-filter (class F7) captures particles larger than 1 μm size. In the combined filter (class H13), micro-particles smaller than 1 μm are bound, and activated carbon neutralizes harmful gases. The units are connectable to Ersa soldering stations and rework systems, and thus supply effective protection. This creates a healthy work environment and operators are protected against illnesses. www.kurtzersa.de Products for battery thermal management Electrolube’s thermal gap filler, GF400, is a highly effective heat transfer solution, providing excellent thermal performance at 4.0 W/m.K. The two-part, liquid siliconebased filler is ideal for a PCB placed in an aluminium casing, filling potential voids with material and improves the transfer of heat, improving reliability. GF400 is a thick liquid that can easily be applied around different shaped housings with low stress on components. Following application, the gap filler can be cured at room temperature or accelerated with heat, with a wide operating temperature range between –50 to +200 °C. The low viscosity of GF400 enables easier dispensing and following curing, it forms a low modulus elastomer, preventing the pump-out phenomenon of the thermal interface layer from the bond line. HTCPX non-silicone heat transfer compound Plus Xtra provides the ultimate in thermal conductivity together with the advantage of using a non-silicone base oil. The exceptional properties obtained from HTCPX are due to the novel use of various metal oxide (ceramic) powders. These materials are electrically insulative to ensure that leakage currents can not be formed if the paste should come into contact with other parts of the assembly. HTCPX has excellent thermal conductivity at 3.40 W/m.K and provides a wide operating temperature range from –50 °C to +180 °C. Designed for gap filling applications, the non-silicone heat transfer compound is vibration stable, low in toxicity and upholds excellent non-creep characteristics. To achieve prolonged battery life and higher efficiency, the thermally conductive epoxy potting compound, ER2221, is a highly thermally conductive resin with low viscosity, ideal for potting cells within electric vehicle batteries. The UL94 V-0 approved epoxy potting compound can withstand long durations at high temperatures and can assist with securing cells in place whilst dissipating the heat away to the surroundings. The resin effectively creates a protective shield around the battery and enables excellent adhesion, high temperature resistance, high thermal conductivity, and retention of characteristics throughout the thermal cycling process. ER2221 is coloured black with an operating temperature of 150 °C and an advanced thermal conductivity value. The company‘s thermally conductive epoxy compounds are ideal for potting cells within electric vehicle batteries. Source: Electrolube The soft and removable PU resin, UR5044, is a high-performance potting compound that allows easy repair and rework in-field with user-friendly resin packs. The material provides protection from extreme and varied environmental factors and is fully UL approved. The flexibility and softness of this resin makes it highly shock absorbent, ideal for battery applications subject to vibration and shock. It provides excellent protection from extreme and varied environmental factors. Ron Jakeman, Managing Director, comments, “We have numerous, versatile solutions that provide excellent protection in a wide range of environments and frequently develop bespoke solutions for our customers if an application presents more of a challenge.” www.electrolube.com Electrolube has developed thermal management and encapsulation resins for better battery protection. Source: Electrolube EPP EUROPE November 2020 27
