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Everwide Newsletter No.171

Experiment § Use Rheometer to measure viscosity change of hot melt Adhesive

In the formulation of hot melt adhesives, there are low molecular weight liquid resins and high molecular weight solid resins. The different tactile and rheological behaviors can be obtained with different proportions. Generally speaking, standard high-molecular-weight solid resins have linear structures; we choose high-molecular-weight resins with branched structures and use a rheometer to compare the rheological behavior of the two. (Figure 1, the resin is placed in the middle of parallel plates, and temperature is controlled to measure the viscosity) The rheological map (Figure 2) shows that at low temperatures, the viscosity of the branch system is much higher than that of the linear system; on the contrary, in the branch system at high temperature, the viscosity is lower than that of a linear system. This feature is critical in development: the use of branched structured hot melt adhesive makes it easier to wet the fiber when the carbon fiber is impregnated at high temperature; the impregnated prepreg has a higher viscosity room temperature, which can reduce the phenomenon of resin sedimentation. The rheometer can set different experimental conditions, including dynamic, static, and steady-state; compared with the general viscometer; it can better grasp the rheological behavior of hot melt adhesives and understand the influence of molecular structure and temperature on viscosity. For relevant information, please refer to the 29th and 30th bi-weekly reports.

─Author: Miss Hui-fang, Lai


Activity § TS16949 Internal audit

Since the implementation of TS16949 in October last year, we have received a lot of education and training, developed new documents, are familiar with the use of the five major tools, and gradually meet the requirements of TS16949. At the end of May, we conducted an internal audit on the production process of the product; the management representative led the relevant colleagues to the site to carry out the internal audit of each step, including feeding, mixing, sub-packing, and warehousing, etc., to understand the defects in the production process. Everyone agrees that TS16949 is much more complicated than ISO9000, and you can't help but the question, "Does it have to be so strict?" The consultant said, "Only perseverance can make a breakthrough!" The colleagues had no choice but to record a lot of defects. After the internal audit activity is over, we will hold an explanatory meeting for everyone to discuss to prevent these defects from happening again. We will continue to implement internal audit activities of other related processes; I believe we will make more progress every time; let's cheer together!


Knowledge § What are the requirements for high reliability?

There are 4 requirements for high reliability:

  1. Then the strength must be high to be able to have a more comprehensive application range and bear enough load;

  2. The variability of the intensity is small so that the quality will not fluctuate;

  3. Excellent durability; after long-term temperature and humidity changes, it withstands repeated mechanical stress, and the strength is maintained within an acceptable range;

  4. Good processability to meet specific mass production needs.

When applying the combination of the design, the material to be bonded, and the adhesive can meet these four conditions; the connection will have a high degree of reliability.


Living § Incredible Germany

Germany is a well-known industrial power; in addition to industry, a robust cultural atmosphere also exists in this rigid country. Schloss Benrath on the outskirts of Dusseldorf is a classical manner that has been preserved in the Middle Ages; the only three remaining buildings tell of its glorious history. The artificial lake in the manor is as vast as ever-wide, isolating the manor from the hustle and bustle of the city on time. Behind the main hall is a long pool with a large group of ducks, like a bright mirror, reflecting the green coniferous forest on both sides. The people jogging and hiking exchanged greetings, which made me feel a warm current, ignoring the low temperature. Some of the cultural relics in the main hall were destroyed by the war, but most of them are well preserved; even the interior decorations, sofas, fabrics, and sculptures are also well maintained, which shows that the Germans have taken care of cultural relics. Through the introduction of the guide, we have a deep understanding of the history and beauty of this manor. Visiting the BMW factory in Munich is my long-awaited itinerary; visitors can learn about stamping, welding, assembly, baking, and other processes. What attracts me most is not the full BMW warehouse but the entire environment and process. The 5S spirit in the factory is thoroughly implemented, and every item is placed in the area where it should be. When personnel wants to pass through the work area, they must walk on the personnel line and not cross the work area. If a tourist who participates in the guided tour accidentally walks into the work area, the guide will also be asked to return to the personnel line. The work pattern of the work team is also something that impresses me: in the assembly process, we will see a group of at least three people. The first one looks at the manufacturing order to prepare parts; the second one performs actions following the SOP on the manufacturing order. The third one is for random quality inspection. The implementation of 5S and the establishment of the work team gave me an excellent experiment class after I just obtained the CQT license.

─Author: Mr. Zhi-Xian, Chen


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