Mechanical drawing is a necessary skill for employees in machinery manufacturing industry.

Many students find it difficult to learn mechanical drawing. The primary reason is that they have not mastered the learning method of painting, and they still study professional courses by studying cultural courses. In the teaching process, students should bear in mind "long alignment, high level and equal width". Don't underestimate these three sentences, which are the core of mechanical drawing. It is also the core of understanding drawings. No matter how complicated the drawings are, they must conform to this principle. (For the drawings of riveted weldments with complex structure, the position of the corresponding steel plate in the structure can be determined by a ruler according to the above principles when looking at the drawings); Second, we should look at more pictures, think more and work harder. (Look at picture 1 again, that is, learn other people's expressions; Thinking more is to think about why others use this expression, as well as the characteristics of various expressions and be familiar with the typical parts of each expression; A diligent hand is to draw more pictures. If you have a chance, you'd better look at the real thing more. ); Third, communicate with teachers and classmates more to understand their habit of looking at pictures. (When marking the size and pulling the serial number, we must consider their habit of looking at pictures. Be sure to mark it in the easiest place to see, to avoid disorderly marking. Remember one thing: your drawings are for others to see! ); Fourth, when drawing, we should abide by national standards, don't ask for speed too early, draw carefully first, practice makes perfect.

Another important reason is the poor spatial imagination. I have always been used to thinking about plane graphics and have a certain plane imagination, but the spatial imagination can't be established. In the process of learning, teachers should help students to establish the concept of space through various modern teaching methods, such as using some physical models in mechanical drawing to analyze students, so that students can change from plane thinking on drawings to spatial thinking in three-dimensional space. The projection of object plane figure is closely related to the actual part model, and they correspond to each other one by one. Let students constantly "from space to plane"

Then "from plane to space"

Practice repeatedly. After a long time, students' spatial imagination and three-dimensional thinking ability will gradually improve. With this spatial imagination and thinking ability, in actual machining and production work, we can imagine three-dimensional objects (three-dimensional shapes of actual parts) in three-dimensional space through the scheme on two-dimensional drawings (parts drawings or assembly drawings). Only by mastering this spatial imagination can we be competent for the processing of parts or the assembly of machines. Therefore, spatial imagination and three-dimensional thinking ability are the core contents of learning and mastering mechanical drawing.

2. Learning mechanical drawing well is an important guarantee for practitioners in mechanical industry to solve practical problems and realize technological innovation.

"Mechanical Drawing" course should not only enable them to learn how to establish their own spatial imagination and three-dimensional thinking ability, but also learn the projection law of points, lines and planes, the drawing of three views and sectional views, the drawing of common parts and standard parts, and the drawing of parts and assembly drawings. They must also master some other related professional basic courses of this major, such as: automobile mechanical foundation, metalworking, mechanism, hydraulic and pneumatic transmission, fitter processing and technology, and lathe processing.

Mechanical drawing is not only a tool for designing and developing new products, but also a carrier of new products, new technologies and new design intentions. Our teachers should innovate boldly in the teaching of this course, improve the traditional teaching methods and ideas, and then integrate new ideas and new teaching methods, which is a new topic and challenge we are facing in the current course teaching. In teaching, teachers should unswervingly carry out this idea, and ask everyone to use their brains, do more, be brave in innovation, and use it for research, and gradually form new thinking methods and learning methods, thus cultivating students' spatial imagination, learning ability and innovative thinking ability.

3. The application of parts drawing and assembly drawing in mechanical drawing in mechanical processing and manufacturing.

Part drawing: A part is the smallest unit of mechanical composition, and it is required to indicate all dimensions of the part (or calculate other dimensions by the indicated dimensions). Assembly drawing: First of all, assembly is to assemble all parts of the machine into a whole machine. Second, the assembly drawing is to clearly express the position of mechanical parts in the machine, and express the internal structure of the machine through cutting lines, which is different from the part drawing. The assembly drawing requires that the tolerance fit of important parts, assembly dimensions, overall dimensions of the machine (convenient for packaging, installation and layout) and technical requirements be indicated. Assembly diagram is a diagram that expresses the assembly relationship of mechanism. In fact, only important fit dimensions and overall range dimensions can be seen in the assembly drawing. Even many equipment drawings don't have one size. The information inside is the serial number and assembly relationship of the parts, and the part drawing is a drawing that expresses the details of the parts, including all the dimensions, tolerances, shape and position tolerances, heat treatment requirements, surface roughness and other requirements of the parts. A machine or a component is assembled by several parts according to certain assembly relationship and technical requirements. Drawings representing machines or parts are called assembly drawings. Construction drawing design is to draw a complete set of construction drawings according to technical design, including general drawing, part drawing, component drawing, product assembly drawing and installation drawing; Formulate lists of general parts, special parts, standard parts, purchased parts and outsourced parts, and lists of raw materials and special materials; Prepare product instructions and instructions for use and maintenance.

Mechanical drawing is a very important basic course for mechanical engineering majors. Mechanical drawing technology has been applied to all aspects of machinery manufacturing. It is a basic skill that engineers and technicians must master. For a practitioner who is about to engage in this industry, he can't stand in the future work without mastering this technical skill.