Experiment § Two-liquid type transparent soil filling for composite materials
After the composite material is hot-pressed and formed, when there are defects or defects on the surface, it is necessary to use soil for modification and leveling (Figure 1). The 128th issue of the electronic newsletter mentioned that solvent-based soil replenishment is suitable for quick repair. Still, it is better to choose reactive soil replenishment (single and double liquid). In terms of two-component soil replenishment, commercially available products often have two main disadvantages: 1. Most of the resin is unsaturated polyester, which has the advantages of low price and good grinding; the disadvantage is that the smell is heavy, and the epoxy resin, the resin substrate adheres poorly. 2. Generally, to grind well and prolong the service life of sandpaper, some inorganic fillers, such as talcum powder, are usually added. The transparency of these products is not good and will obscure the original fiber texture (Figure 2). The solution is straightforward: 1. Choose epoxy resin for filling soil; 2. No matting powder is added to the ingredients. But what is easy said is usually challenging to do. Epoxy resin is organic, and its abrasiveness is not as good as inorganic. It is easy for the manufacturer to feel inefficient and sticky sandpaper. We mix resin, hardener, and filler to achieve a balance between abrasiveness and perspective. Figure 3 shows the soil filling we developed. The upper right of the red box is where the soil has not been ground, and the inside of the red box is the ground part. From this photo, it can be seen that the defects are filled in by soil filling, and the lines on the bottom after grinding are visible, which can meet the needs of customers.
─Author: Mr. Yun-xian, Liu
Activity § New protection weapon-class B protective clothing/SCBA
Last year, we introduced the poison disaster drill of Everwide Chemical. At that time, the poison disaster response team was wearing Class C protective clothing (Figure 1). To protect the safety of the personnel of the response team when dealing with the situation and avoid personal injury caused by direct contact with chemical substances, experts and scholars of the Industrial Technology Research Institute recommend that we increase personnel's protective equipment. In December last year, 4 sets of B-level protective clothing and SCBA air respirators (Figures 2 and 3) were purchased to replace the original C-level protective clothing. The life safety of the response team personnel can be better protected. Class B protective clothing is very similar to the so-called space suit, providing response personnel to isolate chemical substances during disaster prevention operations. Because of the gas that may be harmful to the human body at the accident site, we are equipped with a firefighters' back self-contained breathing apparatus (SCBA) to ensure that the response team can breathe clean air at the accident site to avoid choking. Special attention is paid to the fact that most people think that the cylinder is filled with oxygen, but it is filled with compressed air. Before each operation, we should carefully check the compressed air in the cylinder to ensure that the air respirator can be used safely.
Knowledge & What are the common outgassing measurement standards?
In Issue 159, we introduced "What are the sources and possible effects of Outgassing?" The most common Outgassing measurement standard is ASTM E595-93, "Total Mass Loss and Collected Volatile Condensable Materials from Outgassing in a Vacuum Environment. ". Its measurement method is to place the test piece under a 5 x 10-5 torr vacuum at 125°C for 24 hours. The weight change before and after the experiment is defined as Total Mass Loss (TML%). Next to the heated vacuum path, install a 25°C condensing device to collect volatile condensable materials (CVCM%) under a 5 x 10-5 torr vacuum. Generally speaking, CVCM is more concerned because it may be the most crucial source of pollution for optical components and electronic parts. Many aerospace industries regard TML<1.00% and CVCM<0.10% as the screening threshold when selecting materials; for some semiconductor industries, the required characteristics are more stringent.
Living § Let's jog together!
I haven't had any exercise habits since I was a child because I wouldn't say I like the uncomfortable feeling of sweating, sticky and uncomfortable, which causes my weight to increase. When people are in desperate situations, they change themselves, and so do I. When I first joined the company, I happened to encounter a health check. I initially thought that there should be no major problems with my body, but I didn't know that I received a red notice after the health check. This sudden warning made me caught off guard as if I had failed a big exam. When I went to the hospital for a review, the doctor told me, "If you don't learn to control your weight, you will have to report to the hospital every day." The monologue in my heart was: "I'm still young, won't you?!" The inspection report can't deceive people. I have to start a "sports life." When I don't want to lack food and clothing, the only thing missing is "health." Health is like lost time, which can't be back. Everything is hard at first, and it's even more challenging for a fat man to exercise! I started to exercise one day and every other day. At this time, my weight dropped slightly, but my physique was amazing. It wasn't until the Carnegie course two years ago that I made the promise of jogging every day, and the lecturer helped me organize a group to accompany me, so I used this opportunity for change: running around the industrial zone every morning with colleagues. Strange to say, I gradually fell in love with jogging, and I found time to jog every day! Sometimes I also want to be lazy because of work fatigue, but I know, "No problem, I can keep running whenever I take the first step." Now I have lost a lot of weight and found myself more energetic. Even the doctor praised me for "a lot of improvement," which made me feel delighted! Exercise is not difficult, but the difficulty is the mentality. Whenever we think of something and do not act, we can only stay in the beauty of fantasy forever. If it's just a matter of fact, I'm still a "fat man." You who are reading this article, please set aside some time after getting off work later and get some exercise! In just half an hour, you can reserve your power for the future. We met on the road!
─Author: Mr. Wei-Lin, Zhang
