THE MECHANICAL DESIGN EXPERIENCE OF AN OLD ENGINEER

JUMU实名认证 发表于 2020-05-23 10:19 | 显示全部楼层 | 复制链接分享      上一主题  翻页  下一主题
Mechanical design is often inseparable from your own experience. Of course, you can learn a lot from the accumulation of experience, but it is difficult to leave a deep impression in your mind without personal experience. You do n’t have a certain foundation for others ’experience. It is really not easy to absorb. Ha ha.
Mechanical design runs through the entire process of design, manufacturing, use, and maintenance . The negligence of design will always be reflected in these aspects. It is easy to judge whether it is successful or not. In the design process, it is greatly influenced by manufacturing, which means that good design cannot be separated from manufacturing. The more you understand manufacturing, the more you can improve the design level. The design drawings are put into production. I have n’t seen many of them that can be processed and assembled immediately according to the drawings. It is very common to find a lot of problems in the process of reviewing drawings and processes. It is still the result of repeated discussions after many meetings and researches. The reasons are many. The standardization of drawing and the level of the viewer are one aspect, but the lack of in-depth understanding of the manufacturing process by the designer is the main reason.
How to determine your understanding of manufacturing? The easiest way is to grab a drawing of something you design yourself. Can you tell whether it has been fully manufactured? Casting, forging, turning, pliers, milling, planing, grinding, just like this, certainly not. Who does n’t know who worked in the machine factory for several years? It must be subdivided, and the processes must be fully understood. For example, how to divide the mold during casting, how to place the gate riser, what casting defects may occur, whether the part structure will cause unexpected conditions during heat treatment, how to optimize the part structure, cutting processing The process is virtualized in my mind. A total of several knives, rotation speed, amount of cutting, and even where the iron scraps are flying, the order of each knife, the entire process of the operation of the lathe, miller, and grinder, etc. Only if there is a better foundation.
It ’s not that those who are engaged in design must be able to play lathes, milling machines, and electric welding. However, to know these operating characteristics, take full account of the design. As a person who engages in mechanical design, this is stronger than the electric welding of rocking lathes. There is a place to settle down. In this way, during the design process, some unreasonable structures will be avoided, and the quality of the design will naturally improve a lot, but it is not enough. A craftsman with ten years and eight years of experience can propose more mature details than you (although overall They ca n’t do the design, but how many sleepless nights have been designed with such a result, is n’t it a sloppy sweep? The only solution is to read more books. What others have summarized is usually combined with production, which is the result of hard work. Learn with problems and digest if you think more. Never again say the stupid answer “Just assure concentricity”, the point is that you have already pointed out the method of guaranteeing concentricity, even the mistakes of the predecessors. At this time, no one will call you Xiao Qian, Xiao Zhao, even the boss calls you Qian Gong, Zhao Gong, it is quite respectable. Touching the chin, the beard grew out, the diaper was lost, the child called mom, and the sense of accomplishment came.
However, the design is always for use. A good design must have a little humanity. Design a set of process equipment. After a trial production, the efficiency and quality are good. A few days later, it was found that others abandoned it because the operator scolded the mother. It’s painful to use. And there are many details to pay attention to. Others are operators. If he considers so many factors, he will not still be an operator there. The design is not conducive to use, so it will be eliminated. There are many complete sets of equipment, such as the engine gearbox of the car, which are “very good” during normal operation. It can’t be used. The factory only sells the whole parts. If you don’t want to sell the accessories, there is really no place to add your own reinforcement. I changed a few factories to buy them and put them in a pile. Poor technical transformation. Such things will be heard as long as they have been in the machinery industry for a long time. The use cannot be done without maintenance, and good design can not ignore the maintainability. In a large-scale production line, the key equipment is repaired twice a year in total, but every time the equipment is unloaded eight pieces, the forklift jack crowbar eighteen weapons are not enough, teachers I also have to use my own hands to play a few useful special homes, and the losses caused by the shutdown have exceeded the value of the equipment itself. It is really a speechless ending. A large-scale equipment only needs to completely disassemble the whole machine because of the replacement of an oil seal or something. It is really sad for the designer to use the unit without scolding the design for the offspring.
We not only design on the basis of manufacturing, but also innovate, but we must learn to inherit. Nowadays, the whole society is emphasizing innovation, but we cannot despise innovation as soon as we emphasize innovation. The usual innovations are divided into two types, one is to recombine the old elements of things, and the other is to add some new elements to the old elements. Therefore, it is undeniable that innovative things always contain shadows of old things. As stated in philosophy, new things are negated in affirmation, and affirmation occurs in affirmation. For example, we humans, although said to be the pride of nature, actually, 99% of our genes are the same as gorillas. If humans are not based on inheriting the gorilla’s genes, there is a 1% breakthrough, and the emergence of humans is unimaginable. If someone says that I am ambitious and do not need to inherit the gorilla’s genes, I will make a 100% pure human gene. , Then you will not be able to produce a human being after another 100 million years. Therefore, it is impossible to completely discard old things for innovation. The original thing is like the same dish, and innovation is like a little seasoning. With such a little seasoning, the dish tastes more delicious. But no one just wants a dish for the sake of pure and delicious food. Therefore, we emphasize innovation, but we must not forget inheritance, only inheritance, no innovation, that is conservative, and only innovation, without inheritance, it is a castle in the sky.
The 1: 1 clone may be considered by many as the safest and most cost-effective design method. But as a person engaged in the design industry, cloning is a shameful thing. The so-called one copy, two change and three creation. A concise summary of the designer’s growth path. When I first started, I could only copy, but at the same time copying, I must desperately understand the original designer ’s intentions and thinking, understand the transmission of the entire machine, the interrelationships between various devices, and the relationship between each part. After that, the drawings can be produced, and the drawings can have clear dimensional matching requirements and geometric tolerances. I only know how to draw it, and waffle up a few lines. I feel that the accuracy of the machine is relatively high, so I vigorously lift the precision up to 0.005, 0.002. The signature on the drawing is in the design bar. Claiming to be engaged in is very precise. This kind of ignorance of the so-called so-called mechanical design engineers is everywhere.
Imitating excellent works is a must for every designer. But when designing, one must have one’s own ideas , and one must also have one’s own distinct personality. Over time, one’s own style is formed. The development of style is directly related to one’s artistic qualities and personal accomplishment. What a long-winded person makes is so long-winded. What a stingy person makes is a little kid. The machine made by an irresponsible person is just as irresponsible as the virtue of that person. Being able to have your own design concept and design style is not the same, so that the things you make out have a unique soul. Experts know at a glance that this is a masterpiece by heart.
When you accumulate experience during plagiarism, you must learn with a negative attitude. Checking the information, I want to learn UG programming in 304214709Q group can help you, look at some classic design cases, and design taboos, compared with some things I have contacted, there will be a big improvement. You can operate on the existing machine. Such as: increase the added value of the machine, improve more functions, so that the whole machine has a higher reliability. In order to cater to high-end customers; or to streamline the structure, retain some common functions, reduce costs, and meet the needs of customers who ca n’t afford it and ca n’t use it. If you do this, you can get started with mechanical design. It’s hard to say whether you can be a world-class inventor, huh, huh. But based on years of experience, it is not difficult to combine, mutate, and graft some structures to create something new. Rather than spend a lifetime studying advanced topics such as perpetual motion, or engage in some so-called patents that somehow cannot create any value, it is better to use your limited life to do something that can leave a mark on this beautiful planet. By the time he was too old to die, he would still think at the end of his life. After so many years of life and so many machines running on the earth, it was enough to laugh at Jiuquan.
A true design engineer can take ten years or more. It also requires considerable talents and a diligent and capable environment. Genius is equal to 99% diligence + 1% effort. In fact, it is not that as long as you work hard, there will be achievements. What this sentence says is that if a person does not have that 1% talent for a certain profession, it is useless to work hard. Diligence is a way to discover your talents, and it is one of the necessary conditions for success, not all. Absolutely not.
The principle of material selection for mechanical parts should consider three requirements
1. Requirements for use (primary consideration)
1) Working conditions of parts (shock, impact, high temperature, low temperature, high speed, high load should be treated with caution);
2) Restrictions on the size and quality of parts;
3) The importance of the parts. (The relative importance of the reliability of the whole machine)
2. Process requirements
1) Rough manufacturing (casting, forging, cutting, cutting rods);
2) Mechanical processing;
3) Heat treatment;
4) Surface treatment.
3. Economic requirements
1) Material price (comparison between the cost of rough steel and cold-drawn profiles, precision casting, precision forging, and processing cost,);
2) Processing lot and processing cost;
3) The utilization rate of materials; (such as the specifications of plates, bars, profiles, and reasonable use)
4) Substitute (try to use cheap materials to replace the relatively expensive rare materials, such as the use of ball ink in some wear-resistant parts to replace the copper sleeve, and the oil-containing bearings to replace some of the turning processing. When the speed load is not large, use nylon Replace steel gears or copper worm gears, etc.).
In addition, the supply of local materials must also be considered
1. Basic requirements of mechanical design
a) Pay attention to the coordination and balance of the machine function requirements! Prevent the barrel effect
b) Requirements for machine economy
Design economy put into production in a short time, recover the consumption during development, and even design while manufacturing
Use economy to have the best performance-price ratio (products start to make a profit in small batches, and then it will be better to change)
2. Basic requirements for the design of mechanical parts
a) Work normally and reliably within the scheduled working period to ensure the various functions of the machine
b) To minimize the production and manufacturing costs of parts
c) Use as many common standard parts as possible in the market
d) For the possible serialized products, consider the versatility of the parts at the beginning of the design as much as possible, and the structure that is not versatile as similar as possible to reduce the workload of process layout and fixture design .

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