Experiment § Use of mold silicone
Many lines and patterns on the appearance of products are made with molds. For example, the hairline crack of the shell of mobile phones and laptops, as well as IMF and IMR products. Mold is the key equipment for this kind of process. Due to the high cost of metal molds and the difficulty of reprocessing operations, a method of reprinting mold silicone as a mold has been developed and applied to film transfer or film transfer. The picture above is the manufacturing process of the membrane transfer plate. First coat UV mold glue on the metal mold (step 1), then cover the mold with PET or PC film for exposure (step 2), After the mold silicone is cured, the structure of the metal mold is overturned on the mold sheet (step 3), Then apply UV glue on the PC or PMMA board, and then press the mold sheet on top of the UV glue for exposure (step 4), after the film is removed, the structure of the mother mold can be imprinted onto the plate (step 5). Due to the low price of molds made by mold silicone, when the mold is damaged, it can be discarded as consumable, so it is often used to replace the metal mold. There are two major requirements for the characteristics of the mold silicone. The first point is good chemical resistance. Long-term contact with the UV glue on the board cannot be easily swollen. The second point is the need for good release properties. The UV glue on the board should be easily separated from the master model after curing. Next time you see the cool appearance of a 3C product, don't forget its complicated craftsmanship!
—Author： Ms. Ya-Ting, Li
Activity § Application of Fresnel lens
The 80-inch rear projection screen that is taller than a human is the theme of our exhibition last year. There is a structure in the screen that is made of a layer of UV glue, and this structure is a Fresnel lens. The application range of this structure is very wide, and it can be a widely used magnifying glass or a rear projection screen. The Fresnel lens is mainly coated with UV glue on the plate and then covered with a structural mold, which is cured by illumination and then re-molded. The seemingly simple manufacturing process has very strict requirements on plastic materials. For example, for sheet adhesion, refractive index, mold reversal, etc., these characteristics must meet certain requirements before they can be combined into a Fresnel lens. Note: The figure on the left is a rear projection TV, and the figure on the right is a magnifying glass made of a Fresnel lens. The thickness of this rear projection is only a little thicker than the projection film, but it has the effect of a magnifying glass.
Knowledge § Why are the curing conditions for resins that are cured at room temperature are "7 days at room temperature"?
The most common room temperature is 25°C. But in fact, room temperature itself is not a stable temperature, and the range between 10 and 40°C is possible. Because the reaction of epoxy resin is related to temperature. A temperature increase of 10°C may increase the reaction rate by a factor of two. When the temperature is lowered by 10°C, the reaction rate maybe only half of the original, so the change of room temperature will drastically affect the reaction rate of the resin. Because of the above, the curing time of epoxy resin at room temperature will be recorded more randomly, in order to respond to changes in room temperature. Certain epoxy resins will be poorly cured at temperatures below 10°C, so it is not easy to produce good strength in any case. Therefore, special attention should be paid to the curing environment below 10°C.
Living § Operation certificate of stacker
On-site handling operations often require the use of stackers. According to regulations, the staff must first participate in an 18-hour training course and then apply for the verification test of the stacker, and then they can obtain the operation certificate after passing. There are two types of examination methods. One is the "National Technician Certification", which has about 3 stages in a year. The other is similar to the "test-and-evaluate and license-issuing certification" similar to the car driving license test. As long as the number of applicants is sufficient, the test will be held, and I am taking the second type of certification. The verification items are divided into disciplines and technical subjects. The subject is similar to the automobile and locomotive test. There is an online simulation test on the website of the Executive Yuan Committee of Labor. As long as you practice more on it, you can reach the 60-point pass standard. The technical department is divided into three parts. The first part is the inspection of the stacker's performance before operation. This part is not necessarily successful for many people who are familiar with stackers, and it is even more unfamiliar to me who has never driven a stacker. During the exam, perform static performance inspections item by item in accordance with the record sheet (not to start the engine). If you accidentally start the engine while checking the indicator lights on the dashboard, you will lose your qualifications for the exam on the spot. The exam must find 4 faults within 15 minutes and repeat them to the chief examiner in order. For example, check the cooling water level, whether the horn will sound, and tire screws. The second part is to complete the prescribed route forwarding, reversing, and parking within 15 minutes during the basic driving process of the stacker. The route is S-shaped. If you hit the line on the way, you must drive back to the original point and travel again. However, the time of the re-start process will continue to be timed, so too many mistakes cannot be made, otherwise, the time will be insufficient. This part of the exam should be passed as long as we are a little careful. It rained heavily during the exam and my vision was a bit blurred, but in the end, it passed smoothly. The third part is the warehouse loading and unloading operation of the stacker, which is also recognized as the most difficult part. In this part, we must deliver the pallets to the designated shelf according to the designated route within 15 minutes, and then put the pallets on the shelf to another shelf in sequence. During the course of the driving route, we must complete 8 times about 90 ° turn, and can not hit the pole at the turn. Except for the width of the stacker, the gap in the curve is less than 20 cm. Therefore, the angle of the steering wheel must be corrected all the time when turning in order to pass smoothly. It took me more than 14 minutes for this test, and I had to retake it if I was not careful. Finally, I successfully passed the exam to obtain a license. At present, there are about 20 employees in the company taking the examination and obtaining certificates, and we will put what we have learned to the job.
—Author： Mrs. Xin-Xin, Shi
