Mechanical design teaches how to apply theoretical techniques and empirical methods to production practice, so this course is highly design-oriented, diverse and practical. In the new situation, the country vigorously promotes the construction of an innovative country, the core of which is the independent innovation capability as the strategic base of development, thus requiring university courses to encourage and stimulate the creative motivation of students.
However, at present, college students generally have the problem of poor practical and hands-on ability, not to mention innovative thinking and creative ability. This leads to a certain disconnect between students’ abilities and the needs of society. The reason is that objectively this course has many and scattered knowledge points, few experimental equipments per capita and limited practical activities, students have little or no opportunity to contact with actual engineering in the early stage, which will add difficulties to teaching and learning, and therefore need to be overcome by good teaching methods. However, the current problems in traditional teaching cannot solve the objective difficulties and fetter the development of students’ comprehensive ability.
1 Problems of traditional teaching
The following problems generally exist in the teaching of mechanical design in universities at present.
(1) Students’ interest is insufficient, and their enthusiasm and initiative are not strong. Because the mechanical design course is very comprehensive and closely related to practice, for students who just transferred from basic course to professional basic course, the course content is relatively complex and abstract, coupled with the lack of practical experience of students, it is difficult to understand the knowledge points in place. These problems lead to the lack of students’ interest in the mechanical design course, and it is difficult to mobilize their learning enthusiasm and initiative.
(2) Students’ practical hands-on ability is not strong. Compared with the boring classroom theory learning, students are more interested in hands-on experiments, but due to limited experimental conditions and safety and other factors, experimental teaching units can often only arrange for students to carry out a few limited experimental projects, and mostly in the ready-made model to observe the movement of the mechanism or mapping, the actual participation of students is not high, let alone the students to participate in the design or improvement of experiments. The students’ hands-on ability is not improved much.
(3) It is difficult to improve the creative ability of students. For many years, the mechanical design course design topics have been limited to the overall design of the secondary cylindrical / helical gear reducer, the design object can be mechanical design textbook belt drive, gear drive, shaft, bearings and most of the content are applied into, can be said to be a complete review of the mechanical design course content and use. But everyone is the same topic, only the specific parameters are slightly different, design ideas and steps have become a fixed pattern, seriously affect the creativity of students, you can imagine, the effect of the course design is worrying.
(4) single form of assessment. Mechanical design examination is generally in the form of closed-book, focusing on the examination of the students’ mastery of the basic theoretical knowledge of general parts, and less on the design and analysis of practical engineering problems, which can not reflect the innovative ability of students. Although the course design adopts the form of one-on-one defense, the assessment focuses on the errors in the drawings and the degree of knowledge of the design content, but does not give more targeted guidance to the students’ innovation in the design, which cannot play a role in inspiring students’ innovative thinking.
Therefore, the traditional teaching contents and methods can no longer fully meet the teaching needs of cultivating excellent technical talents in the new era and give full play to the functions of cultivating talents, knowledge transmission and innovation and serving the society in colleges and universities. Then it is necessary for teachers to reform the existing teaching methods and approaches, strictly control the quality of teaching and practical links, not only to make students master the basic theoretical knowledge of universal parts design, but also to focus on cultivating their innovation and practical ability.
2 Reform and innovation of teaching contents and methods
(1) Innovation of classroom teaching
Classroom teaching is the basis for students to conduct experiments and practice, so the first step is to arouse students’ interest in learning and motivate them to learn, then it is necessary to integrate innovation into classroom teaching.
First, teachers need to change the previous “full classroom” teaching method, in order to stimulate students’ active thinking, they should adopt flexible lecture methods and approaches to inspire students’ ideas, especially to create opportunities for students to think and academic discussion. For example, when teaching “gear transmission” chapter content, the need for the content of the previous section near the end of the actual problems related to gear transmission; briefly introduce the gear transmission load and working conditions required, require students to think after class to analyze: what gear transmission form should be used, how to design the specific parameters of the gear, etc.. In the next class, a few students will present their design solutions, and other students will evaluate their solutions, give comments and suggestions, and improve and refine the solutions. Based on the discussion, the most suitable design will be determined. Finally, the teacher will summarize and conclude. In addition, through this kind of thinking and discussion, students can also apply and consolidate the knowledge they have learned before and improve their ability to analyze and solve problems.
Second, the classroom lecture content needs to be adjusted, because it takes a long time to prepare and publish the textbook, resulting in the content of the textbook lagging with the theories and technologies at the forefront of the development of the discipline. Therefore, in order to expand students’ horizons and understand the current development of the discipline, teachers should combine their own research topics or consult the latest literature to make certain selections and additions to their classes. Practice has proved that this kind of innovative teaching, teacher-led, student-led form can achieve good interaction between teachers and students, to achieve the “resonance” of thinking, and thus improve the quality of classroom teaching.
(2) Experimental teaching innovation
Experimental teaching is a necessary supplement to classroom teaching, not only to verify theoretical knowledge, but also to improve the students’ hands-on ability. However, for a long time, the limited number of mechanical design experiments also only stay in the demonstration, verification stage, not much benefit to the cultivation of students’ innovative ability. In the experimental class, it is often a group of several students around a piece of equipment to carry out experiments according to the established steps, for some of the experimental phenomena and results, students rarely think about why, this passive acceptance of the situation is obviously not conducive to open up students’ innovative thinking. Therefore, it is necessary to increase investment, increase the number of sets of experimental equipment, and strive to allow each student to experiment with their own hands. In addition, the laboratory can take the form of open management, such as the drive system creative combination of experiments, can be open all day in stages, to facilitate students in the specified period of time at any time to observe, self-study and experiment.
As for the experimental mode, the traditional experimental mode combined with virtual experiments can be used for reform. The traditional experimental mode is that students operate experimental equipment and instruments to complete the prescribed experimental projects. In this process, students often lack of perceptual understanding of the experimental equipment, the actual operation is often many difficulties, so that in the limited experimental class time can not be well observed experimental results. The virtual experiment is a simulation of the experimental project and its process on the computer, in the experimental process, students are controlled by specific courseware to demonstrate the experimental process, which can help students better understand the experimental principles and concepts. Moreover, students can not only conduct virtual experiments in the laboratory, but also experiment on personal computers by copying software or online experiments through the Internet, which makes the experiment not limited by time and space, which not only can improve the teaching effect, but also helps to cultivate students’ practical ability and learning ability.
(3) Curriculum design innovation
To carry out innovative reform of the course design, first of all, the design topics should be varied, using a combination of basic designation and students’ independent selection. Encourage students to choose systems or institutions that are closely related to engineering practice and have some perceptual understanding of them to design. In the specific design process, the principles of variation design and adaptation design can be applied with reference to the design samples. Second, reform the design methods and means. In the design to integrate modern design concepts and methods, such as reliability design, optimization design, but also the introduction of computer technology means. At present, enterprises commonly use auxiliary design software Pro/E, UG, Ansys, etc. For example, UG is used for 3D modeling of the mechanism, followed by CAE analysis of the built virtual model using ANSYS, and then the model is continuously improved according to the analysis results, and finally a virtual model that meets the requirements of innovative design is obtained. Therefore, the researcher also encourages students to use these auxiliary design and analysis software for course design.
(4) Curriculum assessment innovation
The examination is an important means of teaching evaluation and a comprehensive test of students’ learning, which has a very important guiding role for both teachers and students. The researcher divided the examination into four parts: attendance, homework, written test and experiment, and the proportion of each part is set according to the actual situation. Attendance is irregular. Assignments are divided into in-class and out-of-class assignments. In-class assignments are assigned by teachers and submitted immediately to avoid plagiarism, which can better reflect students’ classroom learning. The questions of extra-curricular assignments should be design-oriented, with multiple solutions to encourage students to consult information, search the Internet, and use their knowledge to solve problems, so that they can develop the ability to collect information, organize and summarize information, and analyze and process information. The written test is still in the form of closed book, and the percentage of the written test score is reduced. The experimental grade will be determined by the laboratory teacher according to the specific conditions of the students’ experiments. Through such a comprehensive assessment method, students can be given a more fair, scientific and objective results.
It is proved that through the reform of mechanical design teaching and the cultivation and practice of students’ innovation ability, the teaching effect has been obviously improved, which greatly mobilizes students’ learning interest and enthusiasm, and improves students’ ability to analyze and solve engineering practice problems by using all kinds of related knowledge and information, while students’ innovation ability is obviously enhanced. The improvement and innovation of teaching can lay a solid foundation for the cultivation of comprehensive and innovative mechanical design talents. With the deepening of education reform and around the requirements of the country and society for the cultivation of scientific and technological talents in the new era, the teaching and assessment methods of this course will be further reformed in the future to continuously improve the teaching quality and teaching effect.