Everwide Newsletter No.206

The polymer has viscoelastic properties, so its toughness is related to the state of the test piece and the test conditions. Izod impact strength is the energy (kg-cm/cm) absorbed when the test piece is ruptured when the test piece is hit by an instantaneous high-speed force. Although it is common to use this test method to reflect the toughness of the material, it cannot reflect the performance of the toughness of the material during slow fracture. The fracture mechanics develop the critical energy GIc (J/m2) required for crack growth under slow test conditions. The energy required for crack growth reflects the toughness of the material. This article briefly describes the experimental procedures as follows: Figure 1 is a polymer test piece, with a diamond cutter to cut a gap in the center of the test piece (Figure 2). Place a sharp blade in the cut gap and strike with appropriate force to create a natural crack (Figure 3) to make a single-Edge-Notch Bending test piece ( SENB) then put the test piece in the material testing machine, and use the down pressure mode to break the test piece (Figure 4). Figure 5 shows the position where the diamond cutter cuts ①, the cracks knocked out with the blade ②, and the area where the cracks grow to the fracture during the test ③. Figure 6 shows the experimental stress-strain curve. GIc can be calculated from the values obtained in Figures 5 and 6. Since the calculation process is a bit complicated, it is not explained in this article for the reader. However, it is worth mentioning that this method reflects the toughness of the material when it is defective and can fit the actual use of the material, so it has considerable reference value.

─ Author: Mr Zhan-Yu, Chen

After passing ISO/TS16949 last year, we continue to improve. Especially for the turtle diagram, we spent half a year discussing and modifying it across departments and identifying all the company's processes. For the first re-evaluation in September this year, the auditor gave us a great compliment and recognized that Everwide is a company that earnestly implements ISO and is constantly improving. What is worth mentioning is the spirit of dedication to the team. Many colleagues are still enthusiastic to participate in the promotion of the system even if they do not currently have a case for car products, and even sacrifice the opportunity for employees to travel for this renewal. We want to thank them here for making Everwide better.

Many applications of adhesion, encapsulation, and infusion will conduct thermal shock experiments to evaluate the material's ability to withstand temperature changes in this application. The common failure mode is that the material is cracked. When the high temperature drops rapidly to the low temperature, the resin shrinks violently, and the shrinkage of other materials (such as metals and ceramics) is not so large. Great stress occurs between the two, causing the resin to crack. In other words, reducing the stress between the two can improve the occurrence of cracks. Stress is equal to strain × modulus. Consider from the aspect of reducing strain: a large number of inorganic fillers are added to the resin to reduce the expansion coefficient of the resin. From the perspective of reducing the modulus: reduce the Tg of the resin to make the resin soft. For materials with lower Tg, the temperature range that exhibits hardness becomes smaller, and the shrinkage stress is smaller. Another method to resist cracks is to introduce toughening materials to improve the tolerance of cracks. As for which method to choose, it depends on other conditions of the application.

Before participating in this employee tour, I always heard my friends describe the humanities and scenery of Japan, and I yearn for one day to find out. Thank you the company for giving us an opportunity this year to participate in overseas employee travel. After arriving in Japan, I found that in addition to clean streets, Japan also does a good job in public health! For example, general household water can be drunk directly, public toilets are very clean and toilet paper is provided. Although rubbish may occasionally be seen on the street, the whole is clean and tidy, and there are no graffiti, slogans, or posters on the street lights. The next day, we arrived at the new landmark of Tokyo: Tokyo Skytree. Looking at the cityscape of Tokyo from the observatory, I found that the streets are straight and neatly planned. Because Tokyo has a large population, in order to effectively use the land, the streets seem to be small, and some schools have also built playgrounds or basketball courts on the top floors of school buildings. This time there is a very novel experience: Chiba-shi's suspended monorail. Japan’s transportation is well-known. In addition to its convenience, various trains are also very fresh and interesting. The train runs in the city in a suspended way, which is completely different from the tram we usually take. Although there will be a little shaking, it is a completely different experience! A trip to Japan has taught me a lot and I feel deeply. I hope to bring these wonderful experiences and energies back to Taiwan, continue to use them in my work, and gradually improve my work and gradually become better. Let us work hard together!

─ Author: Mr Yan-Hao, Zhang