Engineering Mechanics Internship Report Fan Wen

Practical purpose: theory and practice, understanding the application of theoretical knowledge in actual production in a specific mechanical field

Practice time: 20 days in the summer of the 2009 school year

Practice location:

Practical content: simple content related to fans

Design of y4-73-11no20f boiler centrifugal induced draft fan

Fan selection manual learning

Cad practice

Mechanical assembly, dynamic balance adjustment, etc.

Practice summary:

Compared with the previous brothers and sisters, my summer social practice can be said to be much luckier. In the wind turbine factory, I received a lot of care instead of going to the factory to move the bricks for a month or other physical activities, as many brothers and sisters said, but did not learn anything more practical. Speaking of it, I think my practice is not so much an "internship", but rather a "learning" because the knowledge I have learned at school is purely theoretical or

The operation of the metalworking internship is almost useless here. Most of my practice in the first five days was sitting in the office of the factory. I believe that no student will learn more through practice than I do. Of course, this kind of practice is not easy. After a month of not taking a bath and not getting a haircut. After studying the final exam in the study room for more than 14 hours, I practice in the summer vacation. I also believe that everyone would rather move underneath. brick. After that, the content is to practice assembly and balance debugging in the workshop. Although it is only the work of screwing the screws, but some of the problems encountered by the masters will explain to me in detail, the theory is The actual application has gained a more thorough understanding, and what I have learned in the office has also played a big role. And I am very happy with the workers.

Through this practice, the most important thing I realize is what kind of use I have learned in school at the factory. At the beginning of the practice, the mechanical principles and materials mechanics exams have just ended. I thought that these things would bring a lot of help to my internship, but in fact, they are almost useless. In the factory, we don't need to calculate the materials through complicated calculations. At least in the factory where I participate in the practice, the commonly used materials are only q235, 16mn, ht250, zg45, etc. The steel is usually only the angle steel and the belt. Steel and strip have not been studied in the relevant courses of the school. I-beams and t-beams may be used more in construction, but the fans are basically not used here, and the use of channel steel is mostly used as a bracket, which is not as troublesome as calculating the torsion in material mechanics. For the heat treatment of steel, it is not required to be so detailed in the transformation of the structure. It is only necessary to know how long it takes to obtain the required strength and stiffness. It is inefficient and unnecessary to check the strength and stiffness of each component and then select the best material accordingly. Many parts have been cast with corresponding standards or corresponding empirical formulas in the manual, and the corresponding parts in the design are also conservatively safe. I didn’t understand why students who graduated from engineering mechanics didn’t find a job. Now I understand that no one will spend money to hire a college student who has the skills to use it. Even so, I am not saying that it is not necessary to study at school. On the contrary, when I find that what I have learned in school is not very useful, I have contradictory feelings that learning such things has a very important meaning. Learning is not about our technology, but our ability, and without such ability, we will be useless in the factory.

In the first few days, by looking at the drawings of y4-73-11no 20f, I have a general understanding of the general working principle of the fan. Of course, the more detailed things can be learned in a few days, and I gave up more detailed research, and then the details were actually understood during the internship in the workshop. The benefits of learning in the factory are reflected: when you can't understand the picture, you can find the corresponding parts in the downstairs workshop, such as impellers and adjustment doors, etc. If you have any questions, you can ask around. Designers, for example, the difference between thrust bearings and support bearings. This type of fan air inlet uses a special style of horseshoe traits. It is very difficult to design and manufacture. It is rarely used. I didn't find the corresponding parts in the workshop. I can only imagine it. The engineering graphics and mechanical principles of the Department of Engineering Mechanics are all b, so I feel that I have not been able to understand more about this aspect and just stay on the surface. Of course, I have already read a set of fan drawings, I can fully understand. As for the actual processing, I didn’t learn enough and didn’t have enough time to study. After all, I read Jida instead of “Technology” and wanted to learn the craftsmanship of the workers. The masters told me: “There is no two years to come.”

I didn't work too long on the "Manual Handbook for Ventilation Selection". I only looked at the previous drawings and I couldn't read more than 200 pages, because the things inside are so too professional that I can't understand for a short time. . When I was studying at school, we all felt that the theoretical part of the textbook was better understood than the formula part. After reading the professional books, I felt the opposite: through studying and training in school, I think the formulas in this book are all It's not that hard, but the part of the professional narrative is really unreadable. When learning the course of calculus probability complex function mathematical physics equations, we all complained: What is the use of such lessons? In fact, I feel that when I read the manual, these courses are a kind of mental exercise for us. Let us have the ability to perform numerical analysis, otherwise I will be mad when I see so many abstract symbol graphics and formulas. Of course, if I let me calculate the full static pressure wind speed now, although I think it is relatively simple, I really don't have that skill.

My father also worked on wind turbines for more than ten years and has a lot of achievements. When I was a child, I also went to the Siping City blower factory. It may be because I was too close to such a field. I always felt that the fan had no technical content, but it was a few The blades are turning and then bringing out some wind. After reading the drawings and manuals, I found out that this is not a simple and rude thing. When working, whether to use centrifugal fan or axial fan left-handed or right-handed low-pressure or high-pressure d or c, etc. Although it's not a delicate machine that doesn't have to be as sophisticated as an electronic product, it can be affected in many ways. On the second day of my practice, a designer in the office called the merchant and said that the manufacturer who ordered the fan had an altitude, and the fan was affected by atmospheric pressure when working. It may be problematic to use a standard fan. The complexity of the fan design is evident. Of course, if you go to the assembly shop to see it, many of the content is still very easy to understand, and compared with car airplanes, the fan should be a relatively simple mechanical industry. There are no specific wind turbines in the university, but there are related important courses: the fluid mechanics I will study in the next semester. It is said that this course is not very good, and it is characterized by a large number of empirical formulas. It seems that I have to be extraordinarily serious when I study in the next semester.

While practicing cad drawing, I think the Tsinghua Tianhe pccad used in the factory is much more convenient than the autocad used in the school. In the last national junior engineering graphics design course, I drew all the cad diagrams of the oil pump parts of my group. In contrast, the complicated operation made me do a lot of useless work. If I used the PCCAD of Tsinghua Tianhe at the time, I think it will save a lot of effort. For example, when using autocad, the dimensional tolerances should be entered with a specific command. When the surface roughness is marked, the block should be created. The hatching may sometimes not be filled due to the discontinuity of the graphics. These are not so-called “soil roads”. It is the method taught by the teacher in class. Pccad saves these troubles. Almost all operations have corresponding options. Dimensional tolerances only need to be double-clicked to modify the roughness. Roughness can be found in the common commands of pccad, and the hatch view can be filled far away. Even when we used auto, the size of the drawings needed to be drawn by ourselves, and pc did not have such a necessity. I haven't used cad for a long time, I feel very unfamiliar. I will practice it often for such important tools.

And what I learned in the workshop later, I personally think it is more practical. As several masters have said, in theory, things have encountered problems in practice, and the knowledge of books can not be solved well, not to mention the books. Of course, such details have not been learned in the short-term practice, but also have a lot of experience. In the workshop, all I can do is to occasionally screw the screws or help the master to hand over something. Most of the time I am observing the work of the masters. Through such practical exercises, the questions left in the first week were answered. For example, when installing the bearing housing, although the actual fan model I saw was different from the one I had seen before, After all, the obvious difference is that the d-type fan thrust bearing and the support bearing are installed in a bearing housing. The impeller is mounted on the same side of the two bearings, so the problem of the bearing housing is naturally clear, and the processing and assembly process is also Familiar with it. Before that, I always thought that the assembly was not too high technical requirements. After reading the operation of the masters and listening to the explanations, I found that this view is completely wrong. For example, installing a bearing is a complete technical activity. The bearing assembly I saw in the bearing housing assembly is an interference fit. It needs to be hot-mounted. Before the installation, the bearing should be heated to a Baidu in the oil and then mounted on the spindle. If the bearing is unevenly heated or not pushed during installation. In the end, the bearing is stuck on the main shaft, and it may be wasted to process the bearing in one afternoon. Other details, such as the bearing can not be placed directly on the ground to avoid ash, the bearing box has not been subjected to aging treatment, it is necessary to grind the angle at the edge portion to avoid the bearing housing deformation after the bearing housing deformation, some components can not be assembled, and the accessories should be shipped together. And so on are all experiences that are not in the book.

Similarly, in the workshop I can also find that many things are not detailed in the school curriculum. For example, lathe processing, metalworking internships are all used to process the rules of the shaft parts. In fact, some of the inner holes of the bearings need to be machined in addition to the trampoline. In the metalworking practice class, we I can't imagine that a bulky bearing box can get stuck on a lathe chuck, and in fact, yes. For example, during the milling internship, the teacher only mentioned that the milling machine can be used to machine the keyway. But the milling cutters we saw are all disc-shaped. I saw that the milling machine used the milling machine to process the keyway. I didn’t react. This is the milling machine because The knives are completely different from what I saw in the factory. In the mechanical principle class, the tenth chapter on the dynamic and static balance course, we mainly learn the methods and calculations for the dynamic balance of the shaft class. In fact, the balance of the fan needs to be balanced is the disk part impeller, and processing The resulting spindle has basically reached equilibrium conditions without balancing. When balancing the impeller, the balancing machine needs to be operated correctly. The first treatment requires a large value balance adjustment. The adjustment method is to weld the balance block of the corresponding mass at the corresponding angular position. Pay attention to the working mode of the welding motor when welding, that is, pay attention to turn off the balance machine to avoid loop Cause damage. Whether it is welding the balance block or grinding is required to be based on the difference in quality. Weigh the balance block We can use the balance to weigh the quality, but the grinding requires a lot of experience to know how many grams of the part that we are grinding. If the balance is not good, it may not be possible for the impeller to meet the requirements for several hours. If the difference between the ideal equilibrium state on the balancer is below 3g, the balance requirement is reached. After doing more than a dozen impellers, I believe that I have fully mastered how to balance the impeller. To be honest, balancing the impeller is really not a very safe job. Many accidents are easy to happen and the consequences are unimaginable. But then again, in the workshop, what kind of work is really safe? Even if you don't work, just standing on the side is dangerous. Once, I was adjusted to the threshold, and after a few steps I stepped on the smooth steel plate and finally fell. When I got up, I found that the coupling that was just a few hundred degrees Celsius just after the hot installation was less than one meter away from me. The distance, if it is met with the disfigurement is affirmative, scares me out of a cold sweat. A master named Lu gave me some work accidents that he had seen when he was young. He learned a lot. He did not really put safety in the workshop. He really needs to pay attention in the future. Otherwise, it is likely to be caused. At first, one of my own was careless and hated for life. There is also some experience, for example, he said that he was naughty when he was young. When he was repairing a car, he sat on a fuel tank that had not used the daily wind and sun for a few years. As a result, Mars jumped when welding. In the fuel tank, after a loud noise, a fire group flew out, and the smoke spread over the hand and disappeared after a long time. Nobody was injured. Things like fuel tanks and oil drums, even if they are vacant for decades, can’t be fired. Who would have heard of anyone who knows? Water welding is often used with caution when cutting or welding tanks.

In the end, what is technical life, only knows when you really work in the workshop. In the simplest case, the crane on the roof of the workshop is just controlling the front, back, left and right. You will think that a normal person can learn, but can you say that this work is not technical? One afternoon, the master who used to drive the crane left for a while. At that time, he was still balancing the axis. He was forced to find a welding master who would drive the crane to take over for a while. As a result, his crane was really unable to drive me. Compliment, the chain almost went to the balance machine. Finally, I realized that the workers are the hardest. It is dangerous to have the skills to have physical work and fatigue. The party constitution stipulates that "the Chinese Communist Party is the vanguard of the Chinese working class." This is indeed a reason. The working class is not easy...

In addition to work skills, I also learned some aspects of working methods that can only be understood through work. For example, how to look at the statistics of the drawings and check the types and quantities of the parts before buying the workpieces; the wind turbines are competitive but should communicate and help, and when the factory is not enough, the workers can be contracted out or hired by other factories. To make it; how the workers in the factory should be arranged to be more efficient, even saying that a group of meals is better than other factories will trigger the enthusiasm of the workers; together with the workers and masters, you can find some industrial opportunities. If there is a chance in the future, how can I start my own career? These may be a lot of things in the society. Students don’t need to go to school, but after all, we have to work. We have to make money. We want to be in society. Mixing us depends on these experiences to survive, and these experiences are equally important compared to work technology.

What I learned in the factory is practical and precious is really impossible to learn in school. Unfortunately, at the end of July, they will participate in the New Oriental English Intensive Course, so the internship time is only a short 20 days. But what I have learned in the past 20 days has enriched my summer vacation and made me have a direction in my junior year or four years of study. I will not be at a loss when I participate in internship practice and even graduate to work.

Originally thought that after more than ten years of hard work, we can finally work like a white-collar worker in a movie and TV series with an ideal salary and a comfortable sitting in the office. In fact, after graduation, the places where we can work must stay close to the factory, and every day we hear harsh sounds of processing; we have to go to the workshop from time to time to understand the actual problems in processing, the clothes we just wore in the morning. It will be dusty and oily; we should pay attention to the lathe around us and the overhead crane. Because the danger is around, we may lose an arm or even wake up again; we may take a break from work and Colleagues make a joke, but even these jokes are inseparable from the content of their work... Even if our career is successful, even if we make a great contribution to this society, even if we leave deeper for our life experience The imprint, we are still workers, we still live at the bottom of society, we still have to work harder. Graduates of business schools may be able to recover nearly a million in an investment. Law school graduates may be able to win a career in a lawsuit. Graduates of liberal arts colleges may be famous for writing a book, but we can't, we only We can work hard and work hard, one millimeter and one millimeter, regardless of the position. But we have no choice, we will not regret it, we will be proud of it, because we are students of engineering, our choice is machinery.