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Everwide Newsletter No.268


Experiment § Tear strength surface after rupture

Test of tear strength (Figure 1). In addition to the strength data, the surface condition of the test piece is often discussed: the adhesive only remains on one of the surfaces, and the strength is usually not good (Figure 2). The thickness of the adhesive remaining on both sides of the test piece in FIG. 3 is approximately equal, and the adhesive residue in FIG. 4 is thin on one side and thick on the other. The adhesive of the former is relatively soft. From a microscopic point of view, when the thickness of the test piece increases, the adhesive shrinks inward, and the front edge may also produce voids with volume expansion, so the cracks will grow from the middle, and the thickness of the residual adhesive on the two sides is about the same. (Figure 5). When the rigidity of the adhesive is high, the deformation of the adhesive under stress on the test piece will be small, and the stress will be concentrated at the position where the aluminum piece and the adhesive are connected, and the crack will grow from there, so the residual glue on both sides of the test piece is not equal (Figure 6,7). As far as tear strength is concerned, the strength of the latter is often better than the former, and the rupture energy is not necessarily lower. The phenomenon of the residual glue of the test piece is related to the rupture mode: when the formula considers heat resistance and mechanical properties, it will affect the rupture of the test piece, but it has no relations with the subsequent shear strength, tear strength, rupture energy, etc.

—Author: Miss. Li-Ling, Liu

 

Activity § Key performance indicator advocacy activities

Following the process-oriented spirit of ISO9001 and IATF16949, we summarize the company's operating activities into a customer-oriented process (COP), support process (SP),and management process (MP), a total of 14 processes. Then, starting from the company's vision and business strategy, analyze the potential risks in the operation of the process, and determine the method of risk control. Finally, the team members responsible for each process design appropriate key performance indicators (KPI). In the first quarter of each year, we announce the KPI of each process to colleagues in all departments. The teacher told us that designing KPI means defining what is right; advocating KPIs requires everyone to do the right things together. Through daily KPI control, we can always remind us to walk in the right way.

 

Knowledge § What is the difference between Tg and HDT?

Glass transition temperature (Tg) is a thermodynamic feature of polymers. It has a rigorous definition: the temperature at which 4 to 5 links in the molecular chain swing to the adjacent free volume. This behavior will change the specific heat, thermal expansion coefficient, storage modulus, loss modulus, and dielectric properties, so Tg can be measured with different instruments. Heat distortion temperature (HDT) is an engineering concept. The material is made into a specific test piece, which is placed in an instrument and pressed down with a specific weight while increasing the temperature. When the material becomes soft, it deforms to a specific size under the pressure of a heavy object, and the temperature at this time is called HDT. Adding fibers to the resin has a relatively small effect on Tg because the polymer material will still move in the original mode, but it will have a great impact on HDT because the fiber will make the material difficult to bend and require a higher temperature material, So a better temperature is needed for the material to have the same amount of deformation.

 

Living § Pure New Zealand

At the age of 43, I took my wife and child on a journey to New Zealand for the first time. I was shocked and sighed. New Zealand is a pure country. In order to avoid environmental pollution, strict inspections are started from the customs security inspection of imported agricultural products. We pack all the snacks into a bag, and the customs confirms the contents of the declaration form one by one before granting the exemption channel to the customs. The blue of the lake in New Zealand, coupled with the color of the rental car, is really incompatible with the natural land. New Zealand is very similar to Taiwan, even the fruits sold in supermarkets are exactly the same. When you go to a Chinese restaurant, you can speak Chinese directly. When we go to Cromwell that a fruit town famous for its fruit, we also met a girl from Taiwan who came to work. There are countless sheep on the way, and if the car stops, they will leave in groups. The ducks and seagulls by the lake will fight with each other when they feed on toast. Only then did I realize that seagulls are more fierce than ducks, because of seagulls peck ducks. It takes good weather to set foot on the Forth Glacier. After just five minutes of flight, the Millennium Glacier is underfoot. One person costs NT$5,500, and the 20-minute glacier experience is unforgettable. I drove 1,600 kilometers in eleven days and returned to Hong Kong for eleven hours, and then transferred back to Taiwan. I rested for almost two weeks before recovering. New Zealand is beautiful and it is very confusing, but if you were born as a New Zealander, you should be envious of Taiwan's so diverse and lively! The scenery cannot be eaten, so I am back to reality.

— Author: Mr. Xu-Xian, Lihui



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