With the penetration of computer technology into various fields, computer-aided design (CAD) has also been developed significantly. Among them, AutoCAD course has become a compulsory course for mechanical majors in many colleges and universities, and in recent years, the latest version of CAD has been launched almost every year. In view of the strong practical and operational nature of mechanical CAD courses, the specific teaching methods and assessment methods should be different from those of other courses.

## The effectiveness of the course is measured by its practical application.

Thus, the main reference for the evaluation of the scientific and effective teaching methods and assessment methods of mechanical CAD in universities is the application of students’ knowledge after mastering the course.

### 1 Characteristics of mechanical CAD courses

#### 1.1 Operational importance

The most important feature of CAD software is that it has a convenient human-computer interface with a large number of tools, buttons and command input boxes, and the focus and difficulty of students’ initial learning is to be familiar with the purpose of each tool and button, and then to draw according to the specific size requirements. This shows that the CAD course does not require students to understand a large amount of theoretical knowledge, but rather focuses on the development of practical skills.

#### 1.2 Skill-Based

After the students have mastered the basic CAD operations, they still need to build up a considerable amount of proficiency in the specific drawing process. For example, when drawing a sector, it can be obtained by drawing a circle and then interrupting it, and it can also be obtained by drawing a circular arc. Therefore, for the specific drawing needs to be analyzed to decide which method to choose to draw the most time-saving, labor-saving, its drawing process is full of skills.

#### 1.3 Self-learning

By understanding the specific CAD learning situation of students, some special phenomena were found. Some students are not interested in learning other courses and even seem to be incompetent; however, they are very good and proficient in CAD courses, and the confidence they gain in CAD learning also promotes the progress of other subjects.

### 2 New ideas of teaching AutoCAD courses

CAD, as one of the most important computer-related drawing and design courses in mechanical engineering, has been one of the “young courses” that young students are interested in nowadays, so it is easier for students to accept mechanical CAD than other traditional courses. Some of the common teaching methods of the course will not be discussed here. I would like to introduce some of the more effective methods of reforming AutoCAD in my teaching process.

#### 2.1 Iterative method of integrating examples

The characteristics of the CAD course itself make it different from other courses in that many of its tools have more functions and parameters are more complicated to set, and even forgetting a command is impossible to operate. Therefore, CAD is suitable to be taught in the framework of specific examples, while using a professional drafter’s thinking process about drawing for lectures [2]. After the lecture, the teacher draws the case completely at the same time, and then asks the students to draw it on their own on the computer, and the teacher solves the problems on the spot. Finally, students are required to draw the case on their own with complete mastery. Practice shows that this way of learning not only improves students’ motivation, but also deepens their mastery of what they have learned.

Therefore, the integration of examples need to choose some more typical examples, more to improve student motivation, such as in the explanation of the ellipse and curve, you can choose Tencent penguin logo, student interest is very high, knowledge is also more solid. Not necessarily taught around the mechanical diagram subject to at the beginning, you can choose some vivid and interesting examples: famous trademarks, Logos, cartoons, etc.; when learning three-dimensional, etc. can choose some simple objects that are usually easy to see for simple drawing: buildings (stretching), Rubik’s cube (surface area) and so on. By combining the basic function operation with vivid examples, after raising students’ interest, it is greatly beneficial to the learning of subsequent professional complex mechanical graphics.

### 2.2 Heuristic teaching method

Heuristic teaching refers to the teaching process according to the teaching task and the objective law of learning, giving full play to the leading role of the teacher, attaching importance to the main position of students, and adopting various ways to inspire students’ thinking and mobilize their learning initiative and enthusiasm from the actual students, which is a teaching method to promote students’ lively and happy learning [3]. The key to heuristic teaching is how to ask questions and when to ask questions, the teacher through the introduction of the lesson can set up an interesting thinking context, so as to implicate students’ curiosity, will greatly improve the teaching effect.

As mentioned earlier, the same figure can be obtained through different CAD drawing techniques, with different advantages and disadvantages. The use of straight line and rectangle drawing method to draw the title bar is relatively troublesome, when students are at a loss, you can introduce the UCS coordinate system, offset and modify the command, received a good teaching effect at the same time can further drive the interest of students. For example, before teaching students the knowledge point of matrix, students are asked to draw a Rubik’s cube, and the grid can be taken more appropriately, so the knowledge point of matrix can be introduced appropriately at this time.

## 3 New ideas of assessment methods

The characteristics of mechanical CAD courses are such that the assessment method cannot be limited to a simple closed-book examination.

In order to avoid a single form of closed-book exams, which can easily lead to high scores and low performance, the assessment method for CAD courses, which are more operational, skillful and practical, should not be limited to a one-time final exam [4]. It is difficult to objectively, comprehensively and accurately reflect the real ability of students due to the limitation of the number of contents and time of the final exam. Therefore, the author divided the final assessment form into two parts, one is the usual grade, including the usual class attendance, time for on-line practice and homework completion; the second is the examination part, which is mainly divided into paper-based theory examination and on-line examination. After the reform of the assessment method, it further promotes the students to master the mechanical CAD course comprehensively, not only know how to draw from the theory, but also the practical operation ability to achieve a seamless connection with the employer, avoiding the phenomenon of high score and low ability of students.

## 4 Conclusion

With the increasing integration of computerized information technology and young students, it is difficult to adapt the traditional mechanical CAD teaching methods to the requirements of the new generation of students. As a young teacher, it is more important to keep a seamless connection with students’ learning ideas, which requires teachers to think differently and find new ideas for happy learning that meet students’ will to learn.