Exploration of teaching reform of “metal cutting machine tools” course

  Metal cutting machine tools are the main equipment for processing machine parts and are the machines for manufacturing machines, which occupy an extremely important position in the machinery manufacturing industry. The course of “metal cutting machine tools” (hereinafter referred to as “machine tools”) is the core professional course of mechanism, and the teaching quality of the course has an important impact on the work of students in the machinery manufacturing industry.

According to the characteristics of the course, combined with years of teaching experience, the author from the teaching content, teaching methods, teaching methods, teaching practices, assessment methods, etc., some useful reform attempts, and achieved a good practical effect.

 Highlighting the topicality and systematicity of teaching contents

  (A) The period of teaching content

  The selection of course content should be compatible with the level of technical development of the discipline, reflecting the latest knowledge and development direction of the industry. The old and outdated content should be compressed or deleted, and new institutions, new systems, new technologies and other content should be added. To this end, teachers must carefully design lesson plans to seize the key points, while simplifying the original teaching content. The “Introduction to Machine Tools” part of the content can no longer be limited to the traditional general-purpose machine tools, to focus on supplementing CNC technology, CNC programming knowledge, increase the “CNC machine tools” section of the proportion of class time, and flexible manufacturing systems, computer-integrated manufacturing systems, these advanced Manufacturing technology field for a comprehensive introduction, broaden the professional knowledge of students, develop professional vision. Of course, the traditional general-purpose machine tools should be clear about their uses, working principles, movement and main mechanisms, special machine tools, combined machine tools to focus on the relationship between machine design and process solutions.

  (B) the systematic nature of teaching content

  ”Machine Tools” course content is complicated, each chapter is relatively independent, not closely linked. More terms, charts, information, practical, lack of systematic content . This requires teachers to optimize the integration of course content when organizing teaching activities, summarize different kinds of machine tools, and find out systematic and regular knowledge for students to master.

For example, from a single chapter on the composition of the content, lathes, milling machines, grinding machines and other chapters on the content and methods are generally consistent, basically the machine tool function, type, composition, transmission system and typical structure of the fixed order. In the course arrangement, can make seemingly unrelated machine tools, in the narrative method, step by step to get unified, to strengthen the integrity of the course and systemic. Such as teaching can focus on the detailed introduction of the above-mentioned content of the lathe, for the simple structure of the grinding machine can be organized according to the steps of the lathe self-study, to find out the two machine tools different mechanisms and transmission principles, not only to save class time, master the knowledge of the course, but also to develop the ability of students to analyze the problem comprehensively.

  Advocating heuristic and discussion-based teaching

  In the past, the teaching of “teaching” emphasizes too much, while ignoring the “learning” effect. Teachers use the “duck-fill” teaching method in class, and students are used to the monotonous mode of teachers speaking and students listening. This teaching method restricts students’ active thinking, increases learning inertia and dependence, and puts students in a passive position in the whole teaching activity .

  (I) Adopting heuristic teaching

  In the teaching process, attention should be paid to the use of heuristic teaching to gradually develop and improve students’ thinking skills. In heuristic teaching, students are the main body of learning, and teachers should play a guiding role. For example, when talking about machining helical cylindrical gears on a gear hobbing machine and determining the calculated displacement of the hob holder and workpiece rotation, the teacher can guidingly ask the question, “How far must the tool move axially along the workpiece when the tooth line of a helical gear is processed similarly to a lathe turning a thread?” The problem is solved when the students think about the situation of turning threads on a lathe.

  (2) Focus on discussion-based teaching

  In other words, after a certain chapter is taught, a discussion class is arranged. The teacher raises questions in the classroom, guides and encourages students to actively think, discuss and answer. The teacher’s one-way teaching is changed to two-way interaction between teachers and students. After a student has finished elaborating, other students with different opinions can express their own views and encourage arguments, without seeking the only answer, and finally the teacher will make a summary. Students can also ask questions to the teacher about the problems they do not understand in class, and the teacher will make heuristic hints and the students will answer, so as to realize the interaction between teaching and learning. For example, after the chapter of “Lathe”, we should discuss “What is the cause of the phenomenon that one end is coarse and one end is fine when machining the outer circle of CA6140 lathe? How to solve it?” Such questions can make the book content and production practice combined, so that students can improve and exercise their ability to analyze and solve problems. Guide students to explore knowledge and learn to discover and innovate in learning.

  Use diversified teaching methods

  ”Machine tools” course is characterized by many diagrams, the introduction of the machine tool drive system, often produce teachers speaking to the wall chart, while students look down from the book diagram of the uncoordinated phenomenon, affecting the progress of the lesson, increasing the difficulty of understanding. Teaching means in addition to classroom narrative, but also can take a variety of forms.

  (A) the use of modern teaching methods

  ”Machine tools” class in some complex institutions, only by the teacher on the plan verbally explain, even if you talk more times, students may still not really understand. Such as learning to open and close the nut and the longitudinal and transverse motorized feed interlocking mechanism in the lathe skate box working principle, just by virtue of the wall chart to speak, the three-dimensional structure on the plan, the students are confused. It can be made into three-dimensional animation, with the help of intuitive and visual graphics and animation to explain, the raw content will be shown visually and graphically, the teacher can explain with less effort, and the students can learn easily. Modern teaching methods, such as multimedia courseware, network teaching platform and teaching video, can maximize the amount of teaching information and improve the teaching effect, while stimulating students’ interest in learning and curiosity, and enlivening the classroom atmosphere.

  (2) Using on-site teaching methods

  To make full use of the advanced teaching equipment, adopt the way of on-site teaching. Some theoretical teaching contents can be moved to the test and practice site for visual teaching, explaining to the machine tool entity, linking the content of the teaching materials with the actual production, receiving twice the effect with half the effort. For example, the structure of CA6140 lathe spindle box and the working principle of the manipulation mechanism are complicated, and it is not easy for students to understand only with the classroom explanation of the wall chart. It is much easier to use transparent machine tools to explain on the spot. Combined with the dismantling experiment of the spindle box, the mechanism principle is clearer, and it can also improve students’ interest in learning and hands-on practice ability, which receives good teaching effect.

  Teaching practice links to strengthen the practicality and innovation

  (A) Practicality of experimental projects

  Experimental teaching is the supplement and continuation of theoretical teaching, its purpose is not only limited to theoretical and practical, but also the more important task is to cultivate students’ hands and brains, and to cultivate their ability to observe, discover, analyze and solve practical problems. Therefore, we should reform the traditional experimental teaching content and methods, try to simulate the way in production, increase the practical experimental content, and focus on highlighting the operation and training of basic experimental skills. For example, the use of scrap machine tools to increase the machine tool spindle box disassembly experiments, remove the drive shaft, gears, using vernier calipers to measure its size, and then draw the structure of the sketch. Students not only develop the skills of disassembly, measurement and drawing, but also learn to use various tools correctly. After doing the experiment, students basically master the disassembly and assembly of mechanical parts, hands-on ability to a higher level, and with the actual production, the benefits of many.   

(B) the innovation of the course design link

  ”Machine tool” course design is a comprehensive application of the theoretical knowledge of machine tools on the basis of students’ learning some professional basic courses, which is the extension and depth of “mechanical parts” course design, and also a preview of graduation design, with important significance [5]. To train students’ independent design ability, should no longer be limited to decades of unchanged general machine tool main drive design, the more information accumulated over the decades, the more students “reference”, the less brainstorming, the less innovation. So should be in the beginning of the “machine tool” design part of the content of the course design task book, diversified topics, a group of two, design machine structure, different parameters, play the initiative of the students, so that they often consider the design of the process of learning, self-reference information, manuals, the purpose is to train students’ innovative ability, to have originality The purpose is to develop students’ innovative ability and give extra points to students with original solutions.

  In addition, the original traditional design methods have not adapted to the requirements of the times, so the introduction of computer-aided design methods in the course design, the application of virtual design software for three-dimensional solid design of machine tools. Such as the use of Solidwork, Pro/E, UG and other software for parts modeling and intelligent assembly, the design of the structure at a glance, you can also add the drive for simulation, to see whether the movement of interference, to meet the design requirements and then generate two-dimensional drawings. This computer-aided design method is closer to the actual situation of modern enterprise production, to lay the technical foundation for students to embark on the workplace.

  Focus on the diversity of assessment methods

  The assessment method is not confined to the traditional closed-book assessment method, changing the single theoretical test to the ability test of the main students, giving full play to the advantages and potential of students. To use a variety of ways of assessment, classroom oral examinations, practical laboratory operations, written examinations and other combinations, the assessment throughout the course, so that students realize that knowledge must live and learn, usually do not listen to the class, the practice of surprise before the examination is not feasible. In addition, through multiple ways of assessment, can also test the ability of students in many aspects, to avoid the disadvantages of “a paper to determine the end”.

  Course design is also a key assessment link, using the instructor to review the drawings, the form of expert defense, strict control. Focus on the assessment of their comprehensive design ability, the ability to analyze and solve problems, and whether there is an original opinion. This also lays the foundation for the graduation design.

  ”Machine tool” class is a practical professional courses, the teaching process not only to teach theoretical knowledge, but also to contact the practical, through a variety of ways, means, methods to strengthen the training of students’ comprehensive ability to improve the quality of teaching. Practice shows that through the above-mentioned series of reforms, the theoretical and practical teaching of the “machine tools” course has achieved the ideal teaching effect, students not only significantly improved their performance, and practical hands-on ability, innovative application ability significantly enhanced. According to the survey of graduates in the past three years, the course of “machine tools” has enabled students to master a large number of professional knowledge in the composition, maintenance and design of machinery and equipment, which effectively shortens the time for students to adapt to the workplace and has been affirmed by the employers.

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