Everwide newsletter No.475

Experiment § Design Direction for Jet Valve Dispensing Products

In recent years, jet valves have become a mainstream dispensing technology due to their high speed and high precision (Fig. 1). Compared with conventional needle dispensing systems, jet valves can achieve dispensing speeds more than 10 times higher and are capable of handling high-viscosity materials with high filler content. To ensure stable jetting performance, product development should focus on three key aspects:1. Filler particle size and orifice compatibility. The particle size of fillers must be properly designed according to the dispensing valve orifice. Excessively large particles can directly cause physical clogging, leading to interruptions in continuous production (Fig. 2). 2. Viscosity behavior under thermal conditions. Jet valves typically operate at elevated temperatures of 40–70°C to reduce viscosity and improve dispensing efficiency. Viscosity should not be evaluated solely based on room-temperature data. For materials showing up to a threefold difference in viscosity at room temperature, the viscosities may converge at 70°C, and in some cases even exhibit a reversal in viscosity ranking (Figs. 3 and 4). This indicates that rheological behavior under heating depends on the intrinsic thermal properties of the raw materials, rather than the assumption that lower viscosity at room temperature will always remain lower at elevated temperatures. 3. Thermal stability and process consistency. Although heating is used to reduce viscosity, it is essential to ensure viscosity stability at the target operating temperature (Fig. 5). The material must remain stable within 5–10 minutes under constant temperature, preventing viscosity fluctuations, stringing, or valve clogging caused by thermally induced reactions. Only through a deep understanding of material properties and precise alignment with application requirements can high-efficiency and stable dispensing products be successfully designed.                                                                                              — Author: Mr. Chen Zhan-Yu

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About Us  § Electrical Equipment Inspection and Guidance

Recently, we attended a “Explosion-Proof Electrical Safety” training course organized by the Safety and Health Technology Center. The course covered electrical hazard prevention and the fundamentals of explosion-proof equipment. Electrical equipment is ubiquitous in both work and daily life. Improper use may lead to electric shock incidents in mild cases, and in severe cases may result in fire or even explosions. During the course, participants learned to identify hazardous areas within the plant, such as cleaning zones and mixing areas. These locations often involve the use of large amounts of solvents, which can lead to the accumulation of flammable vapors. In addition, sparks may be generated during equipment operation; therefore, certified and compliant explosion-proof devices must be used. Through continuous environmental safety education and training, we aim to make “zero incidents and zero risk” a realistic and achievable goal.

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Knowledge § Negative Thermal Expansion (NTE) Fillers

Most materials exhibit a positive coefficient of thermal expansion (CTE), meaning their dimensions increase as temperature rises. For example, epoxy resin in the glassy state has a CTE of approximately 80 ppm/°C, while fused silica exhibits a very low CTE of about 0.5 ppm/°C. A small number of inorganic fillers show contraction upon heating due to changes in bond angles; linear structures may deform into bent configurations, resulting in overall shrinkage. For instance, Zr₂(WO₄)(PO₄)₂ has a thermal expansion coefficient of approximately −3.5 ppm/°C over the temperature range of −100 to 800°C. Some materials undergo crystal phase transitions within specific temperature ranges, leading to significant volumetric contraction. For example, Dowa’s DNP-1 exhibits a thermal expansion coefficient of −27 ppm/°C between 100 and 200°C, while JMTC’s BNFO-15 shows an extremely large negative thermal expansion of −187 ppm/°C between −25 and 25°C.

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Living § Embracing Nature

This weekend, my friends and I planned a relaxing short trip to Hengshan Township, Hsinchu County. We chose a hassle-free glamping-style camper, which was well-equipped and comfortable. There was no need to prepare complicated gear, allowing us to easily enjoy the experience of camping. Upon arrival, we first visited Neiwan Old Street for a walk and tasted Hakka specialties, including wild ginger flower sticky rice dumplings and handmade rice cakes. In the evening, we returned to the campsite. In the slightly chilly weather, we lit a fire, barbecued, and caught up with one another. What was special was that, without any prior agreement, everyone put their phones away that night and focused on face-to-face conversations and eye contact, making the atmosphere especially warm and pleasant. After dinner, the adults enjoyed casual drinks and conversation, while the children ran and played on the grass. The most unforgettable moment was looking up to see the stars shining in the sky—a sight that, in cities covered by light pollution, may only be visible with good eyesight and luck. Early the next morning, the clear sound of birdsong woke me up. As I opened the car window, the scent of fresh earth filled the air—a fragrance that only nature can offer. If you also wish to regain inner peace, you might consider stepping away from the noise of the city and retreating into the mountains and forests for a few days.                                   

   — Author: Ms. Chan si man

Thriving means working hard. Editor: Chan,Si-man/Lin,Yi-Chu Layout: Chan,Si-manE-mail：service@everwide.com.tw