Technical Library | 2015-08-18 14:02:37.0
What is UV Curing? “Ultraviolet (UV) light is an electromagnetic radiation with a wavelength from 400 nm to 100 nm, shorter than that of visible light but longer than X-rays.” (Source: Wikipedia). Ultraviolet or UV curing is used to create a photochemical reaction using high intensity Ultraviolet (UV) energy or “light” to quickly dry inks, adhesives or conformal coatings. Most materials cure with a UV wavelength around 350 ~ 400nm although some materials require UVC energy near 255nm. There are many advantages to using UV curing over other traditional methods of curing. Not only will it increase production speed, it assists in creating a better bond, and improves scratch and solvent resistance. When compared to other methods of curing, UV curing generates a more reliable cured product at a much higher rate of production in a considerably shorter period of time.
Technical Library | 2021-04-21 15:10:16.0
Voids affect the thermal characteristics and mechanical properties of a solder joint, thereby affecting the reliability of the solder interconnect. The automotive sector in particular is requiring the mitigation of solder voids in various electronic control modules to the minimum possible level. Earlier research efforts performed to decrease voids involved varying the reflow profile, paste deposit, paste alloy composition, stencil aperture, and thickness. Due to the various advantages they offer, the use of Ball Grid Array packages is common across all industry sectors. They are also prone to process voiding issues. This study was performed to determine if vacuum assisted reflow process can help alleviate the voids in area array solder joints. Test parameters in this study largely focused on vacuum pressure level and vacuum dwell time.
Technical Library | 2021-06-07 19:10:16.0
The aim of this study was to compare leaching characteristics of metals from printed circuit boards (PCBs), taken from waste electrical and electronic equipment in the presence and in the absence of the iron-oxidizing bacteria, Acidithiobacillus ferrooxidans. A. ferrooxidans not only increases the leached concentration of Cu from the PCBs, but also inhibits the components of the 0K medium and leached Cu from forming precipitates such as libethenite (Cu2(PO4)(OH)), thereby assisting Cu recovery from the PCBs. In addition, the leached concentration of Pb from PCBs decreased in the presence of A. ferrooxidans, due to Pb forming amorphous precipitates. It is expected that Pb is not highly toxic to A. ferrooxidans. Consequently, A. ferrooxidans can be used as a cost-effective and environmentally friendly way to leach out valuable metals from PCBs as low-grade urban ore.
Technical Library | 2022-10-31 18:35:40.0
Voids affect the thermal characteristics and mechanical properties of a solder joint, thereby affecting the reliability of the solder interconnect. The automotive sector in particular is requiring the mitigation of solder voids in various electronic control modules to the minimum possible level. Earlier research efforts performed to decrease voids involved varying the reflow profile, paste deposit, paste alloy composition, stencil aperture, and thickness. Due to the various advantages they offer, the use of Ball Grid Array packages is common across all industry sectors. They are also prone to process voiding issues. This study was performed to determine if vacuum assisted reflow process can help alleviate the voids in area array solder joints. Test parameters in this study largely focused on vacuum pressure level and vacuum dwell time.
Technical Library | 2018-09-21 10:12:53.0
Moisture accumulates during storage and industry practice recommends specific levels of baking to avoid delamination. This paper will discuss the use of capacitance measurements to follow the absorption and desorption behaviour of moisture. The PCB design used in this work, focused on the issue of baking out moisture trapped between copper planes. The PCB was designed with different densities of plated through holes and drilled holes in external copper planes, with capacitance sensors located on the inner layers. For trapped volumes between copper planes, the distance between holes proved to be critical in affecting the desorption rate. For fully saturated PCBs, the desorption time at elevated temperatures was observed to be in the order of hundreds of hours. Finite difference diffusion modelling was carried out for moisture desorption behaviour for plated through holes and drilled holes in copper planes. A meshed copper plane was also modelled evaluating its effectiveness for assisting moisture removal and decreasing bake times. Results also showed, that in certain circumstances, regions of the PCB under copper planes initially increase in moisture during baking.
Technical Library | 2019-10-17 08:44:01.0
There has been an increase in sealing and encapsulation applications mainly in the field of autonomous driving. Safety and assistance systems already make driving safer and more comfortable today. With increasing progress even more electronic systems will be added. The smooth functioning of computers, sensors, cameras, etc. - and thus our safety as road users - also depends on optimally applied potting media. These can be applied economically, quickly and with high quality in individual applications and are now mastered. With the changing mobility concepts, however, the prerequisites in manufacturing are changing. The requirements are often not fixed at the outset, but only develop during the course of the project. The aim here is to generate a flexible standard that enables attractive pricing and short delivery times. However, we are prepared for these developments: with our modular system consisting of scalable system modules. From this, individual processes can be taken and combined according to requirements. Our new LiquiPrep systems have recently become part of this modular system. They represent a further development of the proven A310 product family and enable reliable processing and conveying of self-levelling media. In addition to a significantly more intuitive operation, the LiquiPrep systems also offer higher performance thanks to a new, patented membrane pump and an optimized agitator. Image: Optimally applied sealants and casting materials form the basis for high quality and smooth functioning of the components.
Technical Library | 2019-09-11 23:33:04.0
There are numerous techniques to singulate printed circuit boards after assembly including break-out, routing, wheel cutting and now laser cutting. Lasers have several desirable advantages such as very narrow kerf widths as well as virtually no dust, no mechanical stress, visual pattern recognition and fast set-up changes. The very narrow kerf width resulting from laser ablation and the very tight tolerance of the cutting path placement allows for more usable space on the panel. However, the energy used in the laser cutting process can also create unwanted products on the cut walls as a result of the direct laser ablation. The question raised often is: What are these products, and how far can the creation of such products be mitigated through variation of the laser cutting process, laser parameters and material handling? This paper discusses the type and quantity of the products found on sidewalls of laser depaneled circuit boards and it quantifies the results through measurements of breakdown voltage, as well as electrical impedance. Further this paper discusses mitigation strategies to prevent or limit the amount of change in surface quality as a result of the laser cutting process. Depending on the final application of the circuit board it may prompt a need for proper specification of the expected results in terms of cut surface quality. This in turn will impact the placement of runs and components during layout. It will assist designers and engineers in defining these parameters sufficiently in order to have a predictable quality of the circuit boards after depaneling.
.gif)
