Dimensional control in the mechanical design process is actually a reflection of a person’s design ability. If you do not have the corresponding design ability, the so-called size control cannot be carried out well. Today I would like to share with you a set of basic design processes and methods. Only practical methods can pave the way for you to perfect professional skills.
01 First determine the size of the outsourced functional components
The start of any design should be based on the overall requirements of the solution. First confirm the models and specifications of some outsourced functional components. This can not only get the delivery time, cost and design size, but also evaluate your design. the feasibility of the solution, and one of the very important things for structural design is the design size of the purchased parts.
We can have a general understanding of the so-called outsourced functional components from the image above. Of course there are many other types, I’m just using them as an example. These outsourced functional components can be purchased from suppliers. to confirm design dimensions. Some samples are paper, and some electronic samples provide two-dimensional and three-dimensional drawings of parts (such as Japan SMC pneumatic components, China Airtac pneumatic components and Japan THK wait products).
As a design engineer, the first thing you need to do is to draw the corresponding part structure based on the supplier’s sample, and then draw the corresponding part structure according to the model and specifications you choose. This is your biggest design basis, and that. the thing is fundamentally not false. It will be changed (if it needs to be changed, that only proves that your design plan is wrong, and that it was wrong in the first place).
For example, when we draw a complete feed assembly drawing of a machining center, we need to start from the threaded rod and draw outward, draw the threaded rod first, then the end of the shaft, then the motor base and bearings, then draw other associated elements. parts (Of course, the principle is that you have confirmed the general structure, such as the formation, shape of the machine tool, etc.). The design of many parts is related to each other. One size determines another size. is entirely reasonable and well-founded. There have never been random sizes, each size has its origin and its purpose.
Therefore, for a mechanical structural design engineer, having and being familiar with product samples from product support vendors is a very important basic skill. It is also your most important resource and ability. It’s not just about in-depth study and mastery of technology. , but also the most important is the accumulation and maintenance of supplier networks, which is a process of awakening and ascension.
02 Confirm the design structure
In dealing with mechanical design structures, everyone has their own habits and ways of thinking, which are difficult to unify. However, some traditional structural forms need to be fully understood and mastered, such as how many connection methods for flanges, how. To better manage these connection methods. At the same time, when designing parts, we must not only consider the functional requirements of parts, but also consider the requirements of the processing and assembly process of parts. For high-end products, we even have to consider the functional requirements of the parts. Consider after-sales convenience requirements. Wait, that’s a very comprehensive ability.
A few days ago I was chatting with a friend and mentioned that a college professor had done some private outside work and designed a set of stamping molds for others. When testing the molds there were no problems with the stamping molding, but when the molding was made there were no problems. Parts were removed, they found they could not be removed. It turns out that the mold opening stroke is not enough, which makes it very awkward. This is where the structural processing error occurs. on the function of the product. Full assessment and reflection. From design to procurement, outsourced processing, assembly, debugging, production and after-sales service, you need to think about it. do this work, you will find that you will fall into one of the circumstances mentioned above. A product that should be perfect will be completely changed by your final quilt, or even fail completely.
Where does the ability to manipulate structures come from? It comes from seeing more, drawing more, and thinking more; it comes from your experience designing projects, it comes from the mistakes you’ve made, and of course, most importantly, it comes from the advice of a great teacher (a good teacher). can get you double the result with half the effort, if he just gives you a few tips you can save yourself several months of detours), but good teachers are hard to find, because others don’t owe you nothing, and most importantly, as a workplace rival, others want to see your jokes. So it requires luck.
Actually, my suggestion is that if you don’t have a good teacher in real life, find some drawings, copy them, look at them and think about them. This is the most realistic shortcut for a design engineer, imitation definitely is. a shortcut to personal growth. Don’t just imitate it. I’ve been thinking about innovation since the beginning. As long as I can master the experience of previous people, it is already an amazing ability.
The confirmed design structure here refers to both the overall structure of the product and the structure of the parts that make up the product. This is basically confirmed during the assembly drawing design process. This is why the design engineer can make the drawing. The reason why there are not many is that the overall ability demands too high and cannot be mastered by just playing for a few years.
03 Drawings of design parts (wall thickness)
After confirming the shape of the part, how to confirm the wall thickness of the part is something very confusing for many people. Confirming the wall thickness of the part should consider many factors, such as the shape of the part, shape. material of the part and molding method of the part, heat treatment requirements of the parts, usage intensity of the parts, location of the parts, etc. Only by considering these comprehensive factors can we truly design qualified parts. drawings of parts. Of course, it’s not easy.
The easiest and laziest way is to learn from it (to put it bluntly, copy it). First check if the company you work for has made similar products before and if there are similar parts on the products. Then consider the relevant factors mentioned above. and combine them with the previous products. Use the design dimensions from the drawings to confirm your part design. This is the method with the lowest error rate, because the mistakes you should make have mostly been made by others before you.
Many people in the industry who follow a purely academic path suggest you do mechanical analysis. Don’t listen to them. Most parts do not need and cannot undergo mechanical analysis. Otherwise, what awaits you is to be fired. of the business will not lead to the market. Development speed is all about speed and cost. If you do mechanical analysis every time you design a part, then by the time you come up with this product, the daylily will be cold. and the boss will go and drink the northwest wind.
When you have a certain degree of design ability, you will slowly form your own design principles. What type of structure will you give, what size will you give, what type of materials will you meet and what requirements will be met. are all internalized in the subconscious, there is no need to think about it, it is a very natural thing.
In this regard, try to communicate with people who have gained extensive experience in research and development. Their abilities were obtained with real money, and you can continue to use them if you steal a little. Additionally, people with science and engineering degrees are used to being “teachers.” As long as you humbly ask for advice, you will usually get good results. Even if it is difficult for them to pass on their tips to you, you can. still learn from some basic design attempts. What you can identify and gain by communicating with them is the workplace in which you should operate the most.
There’s an old saying in my hometown: a sweet mouth is worth its weight in gold, as long as the tongue rolls. Often, it is much more helpful to be diligent with your mouth than to be diligent with your hands and feet.
04 Confirm standard parts
As with the outsourced parts mentioned earlier, selecting the standard parts is relatively simple, and once you have selected the standard parts, you will also confirm their structure and size accordingly. During the design process, you should make full use of those parts that can easily be used. confirm the structure and size. The more such parts there are, the more effective your structural treatment will be.
Additionally, when selecting standard parts, there are relatively few selection variables. For example, we can confirm the selected model and specifications from several aspects such as stress range, assembly method, standard parts material, standard parts usage, etc., and then according. on Select the model and specifications to design the corresponding drawings. In fact, current 2D and 3D software all come with standard part libraries, so many graphics only need to be called up directly, you don’t need to draw them. . Of course, the choice of standard parts is not really something that does not have technical content. It’s just a little simpler than designing parts. If you still have no idea, then my suggestion is to learn from others and try what others have done successfully. on the road, at least you are less likely to fall into a pit, because the pits on the road have been filled by the predecessors with their bodies.
05 Mechanical Analysis
Although we use mechanical analysis in relatively few places in the company’s product design process, we still need to perform mechanical analysis where necessary. This is related to the quality and cost of the product. We must save what should be saved and what should be saved. This cannot be done. The province cannot be ignored at all.
There are many ways to perform mechanical analysis. The old traditional way is to look at textbooks, define formulas, look at structures, etc. to calculate. Of course, the last method is to use 3D design software to perform mechanical analysis, which is possible. it is enough to achieve “more, faster, better” the perfect state of the “province”.
To sum up, in fact, in the design process, the most effective training is step-by-step analysis and explanation based on drawings. This cannot be replaced by any article or method. My usual training method is to let new people take it apart. according to my requirements. For parts drawing, draw it according to their intention first, then give it to me to check. I will list all the bad points in the design process, then call him and tell him one by one. how to modify it and why it is like that. Edit, then ask him to modify the drawing based on my explanation. After modifying the drawing, give it to me for review, if there are still problems, I will ask him to modify it again, after several rounds of product. design, A newcomer can basically establish his own preliminary design awareness, and then solidify his design foundation through a large number of product design projects, and gradually develop his own design style and principles, so that he can slowly let go.
To be honest, it’s really not easy to train a qualified design engineer, especially to train a person with all your efforts. Every time I do that, I tell myself that this person is like a knife that I want. to sharpen it and make it an indestructible weapon in the workplace. Every time I think about it, I will have a little comfort in my heart.
Daguang focuses on providing solutions such as precision CNC machining services (3-axis, 4-axis, 5-axis machining), CNC milling, 3D printing and rapid prototyping services.
