Experiment § Evaluation of plastic surface tension
The easiest way to evaluate the surface tension of plastics is to use different numbers of dyne pens (Figure 1) and draw on the surface of the plastic (Figure 2). The ink with dyne value 30 and 32 can be evenly distributed, and the ink above 34 will shrink, which means the surface tension of this material is about 32 (dyne/cm). Many plastic materials are stained with release agents, oil stains... and other contaminants. Wiping with isopropyl alcohol (IPA) can increase the dyne value. For example, the uncleaned dyne value in Figure 3 is about 30-32, and the dyne value after cleaning with IPA is about 34-36. Materials with higher dyne values are easier to be wetted by glue and ink, and have better adhesion effects. Figure 3 shows a large water droplet angle that fails to wet the surface. After the surface is cleaned, the water droplets angle becomes smaller and the wetting effect is improved (Figure 4). The water droplet angles in Figures 3 and 4 are roughly indicated by a protractor on the computer, which has a large error and is only suitable for a rough comparison. The true water droplet angle can only be accurate with a dedicated measuring instrument (Figure 5). The water droplets angle measurement software will use a mathematical equation to simulate the boundary of the water drop, and then use this equation to calculate the angle to the substrate, so that the accurate water drop angle is.
——Author: Mr. Zhi-Yu, Huang
Activity § Rich September
The hot September started after the farewell summer intern, and we began to introduce the ERP personnel system. All applications for absenteeism, leave and overtime are completed online, and new face and fingerprint recognition time attendance machines have also begun to be applied, moving towards paperless electronic forms. The most important IATF16949 transition audit this year will also arrive in September. I thought we were ready, but after two and a half days of baptism, everyone became very tired. The IATF16949 revised version of the provisions is more rigorous and has higher requirements on the supply chain of car manufacturers. Since the revision, the pass rate has been very low. After receiving the main deficiencies mentioned by the Auditor teacher, we also actively held meetings to discuss and modify and improve our system. It is expected that a complete improvement measure can be given within twenty calendar days. Colleagues also went to Vietnam to participate in the exhibition, continuing to explore opportunities in Southeast Asia. As mentioned in the previous issue, the young leaves of the trees that were pruned for typhoon preparation quietly climbed up to the branches, bringing a trace of vitality, as if to inspire us, and hope that we can complete the improvement within the time limit and successfully obtain the IATF16949 certificate. let's work hard together!
Knowledge § How to prevent thermal aging of resin?
Different types of resin have different mechanisms during high-temperature aging. The common thing is that free radicals are generated by chain scission, so adding hindered phenol to capture free radicals is the most basic composition. The free radicals generated by aging will generate peroxides with oxygen and promote the aging reaction, so adding phosphites that decompose peroxides is also a common combination. Some aging reactions will be catalyzed by the metal catalysts inherent in the resin. Finding a way to deactivate these trace components can also delay aging. Some aging products will further accelerate the aging reaction, such as organic acid structures. If these structures can be avoided, they can also be effective countermeasures.
Living § Learn the courage to let go
The first consent to giving up first aid in my life was a decision made many years ago before my family passed away. At the moment, my heart is hard and I resist, and I always think "There should be hope!" "Maybe there will be a miracle!" Later I learned that the plots of dramas and movies will not appear in my life. Doctors are not gods, and there are times when they are helpless. That night, the miracle did not finally come. I endured tears and said goodbye to my family softly. Finally, I signed the document and chose to let go. Soon after, my colleague recommended me to read the book "Say Goodbye to Cruel Kindness". The author Dr. Chen Xiudan is a physician in the intensive care unit. He wrote this book with his own experience and conveyed the concept of "good death" to everyone. Click the picture on the left to learn more about books. Very often family members want to "maintain life," no matter the reason, they always feel that this is "good" for sick relatives and friends. However, the empty eyes and the inability to interact with other family members are really what the patient in bed wants? If they are unwilling to lie in bed every day, with tubes all over their bodies, relying on instruments to maintain their lives, and allowing others to get injections, sputum and feeding, why should we let our family members accept such painful treatment? We don’t know when we will come to the end of our lives. Instead of regretting it in the future, we should cherish the time we spend with our family from now on. Letting go requires a lot of courage. In the most important lesson of life, when facing death, I know how to grasp every moment of the moment and live every day with my heart without leaving any regrets.
—Author: Mr. Heng-Rong, Li
