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Mechanical design often relies on one’s own experience. While a lot can be learned from books, it is difficult to leave a deep impression in one’s mind unless one experiences things firsthand. Without a solid foundation, it is truly not easy to understand and absorb the experiences of others. Hehe. Mechanical design spans the entire process of design, manufacturing, use, and maintenance; oversights made during the design phase will always show up in these aspects, making it easy to determine success or failure. During the design process, manufacturing has a significant influence; in other words, a good design cannot be separated from manufacturing. The more one understands manufacturing, the more it helps to improve the quality of the design. For the designed drawings that are put into production, I’ve seen few cases where they can be manufactured and assembled immediately according to the plans. It’s common to discover numerous problems during the processes of reviewing the drawings and determining the manufacturing methods. Even the drawings prepared by so-called \"experienced\" senior engineers or chief engineers result from multiple meetings and thorough discussions. There are various reasons for this: the standardization of drawing practices and the skill level of those who review the drawings are factors, but the main reason is the design team’s insufficient understanding of manufacturing processes. How can I determine my level of understanding of manufacturing? The simplest way is to pick up any drawing of something you’ve designed and see if you can describe the entire manufacturing process for it. Casting, forging, turning, fitting, milling, planing, grinding – just like that? It definitely won’t work. Who who hasn’t worked in a machinery factory for a few years knows this? It is necessary to break it down in detail to gain a comprehensive understanding of each process. For example, how to determine the parting lines during casting, where to place the gates and risers, what kind of casting defects might arise, whether the part’s structure could lead to any problems during heat treatment, how to optimize the part’s design, envisioning the cutting process in one’s mind – how many tools will be used, the rotation speed, the feed rate, even where the metal shavings will fly, the sequence in which each tool is used, the entire set of actions involved in turning, milling, grinding, and so on. Only by understanding all these aspects can one have a solid foundation. It’s not that those who work in design must necessarily be able to operate lathes and milling machines or know how to weld, but it is important to understand the characteristics of these tasks and take them fully into consideration during the design process. Only by doing so can those working in mechanical design outperform those who simply operate lathes or weld, and thus have a solid foundation for their career. In this way, during the design process, some unreasonable structures can be avoided, and the quality of the design improves significantly. Yet that’s not enough; a technician with eight or ten years of experience can come up with more refined detailed solutions than you (although they may not be able to handle the overall design). Wouldn’t it be a shame to spend so many sleepless nights working on something that ends up being of such poor quality? The only solution is to read more books. What others summarize is usually combined with production and represents the fruit of their hard work. Study with questions in mind; the more you think about it, the better you’ll understand it. I will never again give such a stupid answer like “as long as the concentricity is ensured.” The key is that you have already pointed out the methods to ensure concentricity, as well as the mistakes made by those who came before. At this point, no one calls you Xiao Qian or Xiao Zhao anymore; even the boss addresses you as Engineer Qian or Engineer Zhao – it’s quite respectful, right? Touching my chin – a beard has grown, the diaper is lost, the child is calling for mom; haha, a sense of achievement too. But design is always meant for use; a good design must have a touch of humanity. When a set of processing equipment is designed and put into trial production, if it yields high efficiency and quality, the boss will organize a celebration drink. A few days later, it was found that they had given up using it, as the operator kept cursing. It’s painful to use. And there are so many details to pay attention to; if a mere operator had to consider that many factors, he wouldn’t still be working as an operator. If a design is not user-friendly, it will be phased out. There are many sets of equipment, such as car engines and gearboxes, which work fine when operating normally; but if one small keyway or bearing seat gets damaged, the entire unit becomes unusable. The manufacturer only sells complete units and does not provide spare parts, and there’s no way to repair it on one’s own. After trying several different manufacturers, with a pile of spare parts available, users are forced to avoid using such equipment. As a result, a technical improvement project was initiated – a pitiful attempt at improvement. Anyone who has been in the machinery industry for a long time will have encountered such things. Use inherently requires maintenance, and a good design must not overlook maintainability. On a large production line, the key equipment is repaired only twice a year in total. Yet each time, the equipment has to be completely disassembled; cranes, forklifts, jacks, levers – none of these tools are sufficient. The experienced workers then have to come up with their own specialized tools to carry out the repairs, resulting in downtime losses that exceed the value of the equipment itself. It’s truly a frustrating situation. For a set of large-scale equipment, just to replace an oil seal or something similar, it’s necessary to disassemble the entire unit almost completely. It’s no wonder that the users accuse the designers of creating something utterly useless; it’s truly a pity for those designers. When it comes to design, we must not only base our work on manufacturing but also be innovative; however, it is essential to learn how to build on existing traditions. Now, the whole society emphasizes innovation, but we must not look down on what already exists just because we emphasize innovation. Typical innovation falls into two categories: one is the recombination of the existing elements that make up something, and the other is the addition of new elements to those existing elements. So, in any case, it is undeniable that innovative things always carry some traces of older elements. As philosophy teaches, new things arise from the negation within affirmation, and from affirmation within negation. Take us humans, for example: although we are considered the pride of nature, in reality 99% of our genes are the same as those of gorillas. If humans had not achieved a 1% breakthrough based on inheriting gorilla genes, their existence would have been unimaginable. If someone says that they have the ambition to create a being with 100% purely human genes, without relying on gorilla genes, then even in another hundred million years, it would still be impossible to create such a human being. Therefore, we cannot discard everything old in the name of innovation. The original elements are like a dish, while innovation is like a little seasoning; with this seasoning, the dish tastes even more delicious. But no one comes just for the flavor alone, without any vegetables, and orders just a plate of seasoned dishes. Therefore, we emphasize innovation, but we must not forget inheritance; having only inheritance without innovation leads to conservatism, while having only innovation without inheritance is nothing but a fantasy. A 1:1 clone is likely considered by many to be the safest and most convenient design approach. But for those in the design industry, cloning is a shameful thing. It is said that it involves first copying, then modifying, and finally creating. It succinctly summarizes the path of growth for designers. When first starting out, one can only copy, but while doing so it is necessary to strive to understand the intentions and thinking of the original designer, as well as the way in which the various components of the machine work together, the interconnections between different devices, and the relationship between each individual part. Once this is understood, it becomes possible to create drawings that specify exact dimensional requirements and tolerance constraints. All they did was draw it out, adding a few random lines; since they thought the machine had high precision, they tried their best to increase that precision, aiming for values of 0.005 or 0.002, and then signed their names on the drawing with arrogance in the design section. They claim that what they create is very precise. These meaningless so-called mechanical design engineers are everywhere. Imitating excellent works is a necessary path for every designer. But when it comes to design, one must have their own ideas; people also need to have a distinct personality. Over time, this leads to the development of one’s own style. The formation of such a style is directly related to a person’s artistic taste and personal cultivation. Things created by talkative people are just as talkative, those made by stingy people have a petty character, and the machines produced by irresponsible people are just as irresponsible as those people’s morals. Having one’s own design philosophy and style makes a difference; things created in this way possess a unique soul. An expert can tell at a glance that this is a masterpiece created with care. Once experience is gained through plagiarism, one should approach learning with a critical attitude. By researching, studying more classic design examples as well as design taboos, and comparing them with things one has encountered oneself, significant improvement can be achieved. Surgery can then be performed on existing machines. For example: increasing the added value of the machine, adding more functions, and enhancing the overall reliability of the device. Thereby catering to high-end customers ； Or streamline the structure by retaining only the most commonly used functions, thereby reducing costs and meeting the needs of customers who cannot afford advanced features but also do not need them. By doing this, one can be considered to have begun learning mechanical design. It’s hard to say whether one can become a world-class inventor, haha. But based on one’s many years of experience, it is not difficult to combine certain structures, modify them, and graft them together to create something new. Rather than spending a lifetime studying complex topics like perpetual motion machines, or working on so-called patents that are meaningless and create no value at all, it’s better to use one’s limited life to do things that can leave some mark on this beautiful planet. By then, I will be very old and on my deathbed; I will think that having lived such a long life and having made so many machines operate on Earth, I can die with a smile. A person who can truly be called a mechanical design engineer requires ten years or even more of training. There must also be considerable talent, diligence, and an environment that fosters growth. The idea that genius equals 99% hard work plus 1% inspiration actually doesn’t mean that hard work alone will lead to success. This sentence means that if a person doesn’t possess that 1% of talent for a certain profession, no amount of hard work will help. Diligence is a way to uncover one’s talents; it is one of the necessary conditions for achieving success, but not the only one. Definitely not. The principles for selecting materials for mechanical parts take three aspects into consideration. 1. Operational requirements (primary consideration): 1) The operating conditions of the part (vibration, shock, high temperatures, low temperatures, high speeds, and high loads all require careful attention) ； 2) Restrictions on part size and quality ； 3) The importance of the part. (Relative importance to the overall reliability of the machine) 2. Process requirements: 1) Blank manufacturing (casting, forging, sheet cutting, rod cutting) ； 2) Machining ； 3) Heat treatment ； 4) Surface treatment 3. Economic requirements: 1) Material costs (comparison of the raw material costs and processing costs for ordinary round steel and cold-drawn profiles, as well as precision casting and precision forging.) ； 2) Processing batch size and processing costs ； 3) Material utilization rate ； (Such as the proper utilization of specifications for sheets, bars, and profiles.) 4) Substitution (use inexpensive materials to replace relatively expensive rare materials; for example, use ductile iron in places where wear resistance is required instead of copper sleeves, use lubricated bearings in place of certain components that are machined by turning, and use nylon instead of steel gears or copper worm gears when the speed and load requirements are not high.) Additionally, the availability of local materials must also be taken into consideration. Basic requirements for mechanical design: a) It is important to ensure coordination and balance with regard to the functional requirements of the machine! To prevent the barrel effect from occurring: b) Requirements regarding the economic efficiency of the machine – Design efficiency, enabling the machine to be brought to market in a short time frame so as to recoup the costs incurred during development; sometimes design and manufacturing take place simultaneously. Economic efficiency also means achieving the best possible cost-performance ratio (the product starts to be profitable at small production volumes, and further improvements can then be made). 2. Basic requirements for the design of mechanical parts: a) They must function properly and reliably over the intended period of use, ensuring that all functions of the machine are maintained. b) The production and manufacturing costs of these parts should be minimized as much as possible. c) As many standard components available on the market as possible should be used. d) For products that may be mass-produced, consider the versatility of components as early as possible in the design phase; even if versatility is not possible, ensure that the structures are similar to minimize the complexities involved in the manufacturing process as well as the workload associated with designing fixtures and tools.