Mechanical design runs through the whole process of design, manufacture, use and maintenance, and design negligence will always be reflected in these aspects, so it is easy to judge whether it is successful or not. In the process of design, it is greatly influenced by manufacturing, which means that a good design can not be separated from manufacturing. The more you know about manufacturing, the more helpful it is to improve the design level. I haven't seen many drawings designed and put into production, and I can process and assemble them immediately. It is common to find a large number of problems in the process of drawing review and technology, including the so-called "senior" senior engineer, the drawings produced by the chief engineer, or the results of repeated discussions at many meetings. There are many reasons, such as the standardization of drawings and the level of viewers, but the designer's lack of understanding of manufacturing technology is the main reason. How to judge your manufacturing knowledge? The easiest way is to take a drawing of something you designed. Can you tell the whole manufacturing process? Casting, forging, turning, clamping, milling, planing and grinding are all the same. It is definitely impossible. Who doesn't know who has worked in a machinery factory for several years? We must break it down and fully understand each process. For example, how to divide the mold when casting, how to put the gate and riser, what kind of casting defects may occur, whether the part structure will lead to accidents during heat treatment, how to optimize the part structure, cutting technology, how many knives are always in your mind, speed, feed speed, and even where the iron chips fly, the order of use of each knife, lathe workers, milling workers, grinder workers. Not to say that designers must be able to play with lathes, milling machines and welding, but to know the characteristics of these operations and give them full consideration when designing. As mechanical designers, they are better than those who burn electric welding on the rocking bed, and they can have a place to live. In this way, some unreasonable structures will be avoided in the design process, and the quality of design will naturally be improved a lot, but this is not enough. A mechanic with more than 18 years of service can come up with a more mature and detailed plan than you (although they can't do it as a whole), but how many sleepless nights are designed like this, isn't it gentle to sweep the floor? The only solution is to read more books. What others sum up is usually combined with production and is the crystallization of painstaking efforts. If you study with questions, you can digest them if you think too much. Don't say "just keep concentricity" again. The key is that you pointed out the method to ensure concentricity, even the mistakes of predecessors. At this time, no one calls you Xiao Qian and Xiao Zhao, but even the boss calls you Qian Gong and Zhao Gong, which is quite respectable. Touch the chin, the beard grows, the diaper is lost, the child calls his mother, and the sense of accomplishment comes. However, design is always for use, and good design must have a little humanity. Design a set of technology and equipment to carry out high-efficiency and high-quality trial production. The boss will make a toast. After a few days, I found that people abandoned it because of the curse of the operator. It hurts to use. And there are many details to pay attention to. The other is the operator. If he had considered so many factors, he wouldn't still be an operator there. If the design is not conducive to use, it will be eliminated. There are many complete sets of equipment, such as the engine gearbox of a car, which works "quite well" normally, but one of the small keyways and one bearing position is broken, so the whole set can't be used. The factory only sells the whole piece, not the accessories. There's really no place to add it. It has been bought by several factories and piled up in a pile, and users have to stay away. Such a thing will be seen and heard as long as it has been in the machinery industry for a long time. Use is inseparable from maintenance, and good design cannot ignore maintainability. In a large production line, the key equipment has to be repaired twice a year, but the equipment has to be disassembled into eight pieces each time, and the forklift jack 18 weapons are not enough. Old masters have to use their brains to play with some useful special items to serve them, resulting in the loss of production exceeding the value of the equipment itself. It's really a silent ending. A set of large equipment, just because of replacing an oil seal, will almost completely decompose the whole machine. It is really the designer's sorrow that users don't scold the design for having no children.
Our design is not only based on manufacturing, but also on innovation, but we must learn to inherit. Nowadays, the whole society is emphasizing innovation, but we can't look down on original things as soon as we emphasize innovation. There are usually two kinds of innovations, one is to recombine the old elements that make up things, and the other is to add some new elements to the old elements. Therefore, in any case, it is undeniable that new things always contain the shadow of old things. As philosophy says, all new things are denied in affirmation, and there is affirmation in negation. For example, although we humans are favored by nature, in fact, 99% of our genes are the same as gorillas. If human beings have a breakthrough of 1% on the basis of inheriting gorilla genes, the emergence of human beings is unimaginable. If someone says that I am ambitious and don't need to inherit the gorilla gene, and I make a 1 0,000% pure human gene myself, then you won't have humans in another 100 million years. Therefore, we can't completely abandon the old things for innovation. Original things are like a dish, and innovation is like a little seasoning. With such a little seasoning, the food tastes more delicious. But no one wants a plate of fried seasoning just for pure taste. So we emphasize innovation, but we can't forget inheritance. Only inheritance, no innovation, is conservative, only innovation, no inheritance, is a castle in the air. Cloning may be considered by many people as the safest and most convenient design method. But as a person engaged in the design industry, cloning is a shameful thing. The so-called one copy, two changes and three innovations. This paper briefly summarizes the growth path of designers. At first, we can only copy, but at the same time, we should try our best to understand the original designer's intentions and ideas, understand the transmission of the whole machine, the relationship between various devices and the relationship between various parts. After understanding, you can draw a picture, and there can be clear size matching requirements and shape and position tolerance constraints on the picture. I only know how to draw and talk nonsense. Probably thinking that the accuracy of the machine is relatively high, I desperately raised the accuracy to 0.005 and 0.002, and signed the design column on the drawing. What you claim to do is very complicated. Such so-called mechanical design engineers abound.
Imitating excellent works is the only way for every designer. But when designing, you must have your own ideas, and people must have their own distinctive personality. After a long time, it will form its own style, which is directly related to a person's artistic accomplishment and personal accomplishment. What wordy people make is so wordy, what stingy people make is petty, and the machine made by irresponsible people is as irresponsible as that person's virtue. Being able to have your own design concept and design style is just different, so that what you pound out has a unique soul. An expert can tell at a glance that this is a masterpiece of heart.
When you have accumulated the experience of plagiarism, you should study with a negative attitude. Look up information, read more classic design cases and design taboos, and compare them with some things you have touched, which will greatly improve. You can operate on the existing machine. For example, increase the added value of the machine, improve more functions and make the whole machine have higher reliability. Thereby catering to high-end customers; Or simplify the structure, keep some common functions, reduce costs, and meet the needs of customers who can't afford so many functions. Doing this can be called doing mechanical design and getting started. It's hard to say whether you can become a world-class inventor, hehe. However, it is not difficult to combine, mutate and graft some structures to create something new. Instead of spending a lifetime studying abstruse topics such as perpetual motion machine, or engaging in so-called patents that can't create any value for no reason, it is better to use limited life to do something that can leave some marks on this beautiful planet. At that time, I will die of old age, and when I die, I think that I have lived for so many years and that so many machines have turned around the earth, which is enough to laugh.
A real mechanical design engineer needs ten years or more. You must also have considerable talent and a diligent training environment. Genius equals 99% diligence+1% effort. In fact, it doesn't mean that you will achieve something as long as you work hard. If a person has no 1% talent for a certain profession, it is useless to be diligent. Diligence is a way to discover one's own talent, and it is one of the necessary conditions for achievement, not the whole. Absolutely not.
The material selection principle of mechanical parts should consider three requirements.
1, usage requirements (primary consideration):
1) Working conditions of parts (vibration, impact, high temperature, low temperature, high speed and high load should be treated with caution); ;
2) Restrictions on the size and quality of parts;
3) Importance of parts. (The relative importance to the reliability of the whole machine.
2, process requirements:
1) blank manufacturing (casting, forging, plate cutting, bar cutting);
2) machining;
3) heat treatment;
4) surface treatment;
3. Economic requirements:
1) material price (comparison between the cost of common round steel and cold-drawn profile, precision casting and precision forging blank and processing cost);
2) Processing batch and processing cost;
3) material utilization rate; (For example, the specifications of plates, bars and profiles should be used reasonably)
4) Substitution (try to replace rare materials with cheap materials, such as replacing copper sleeves with nodular cast iron in some wear-resistant parts, replacing some sleeves with oily processing, and replacing steel gears or copper worm wheels with nylon when the speed load is not great).
In addition, we should also consider the supply of local materials.
Basic requirements of mechanical design
A) Pay attention to the coordination and balance of the functional requirements of the machine! Prevent the emergence of barrel effect
B) Requirements for machine economy: design economy, put into production and put into market in a short time, recycle consumption during development, and even manufacture while designing, and use economy should have the best cost performance (products will be better after being made in small batches).
2, the basic requirements of mechanical parts design
A) Work normally and reliably within a predetermined working period to ensure the functions of the machine.
B) Minimize the manufacturing cost of parts.
C) Use as many standard parts as possible.
D) For the products that may be serialized, the generality of parts should be considered as much as possible at the beginning of design, and the structures that are not universal should be similar as much as possible, so as to reduce the workload of process arrangement and fixture design in the manufacturing process.