Research on Productization of Automatic Tool Changing System for CNC Machine Tools
1 Introduction
With the rapid development of modern technology, numerical control (NC) machine tools have been widely used in many industries, especially in precision machining. Automatic tool changing system is one of the most important accessories for modern NC machine tools, which is the necessary guarantee for rapid and accurate processing and is also the basis for medium and small batch production. As an important part of modern manufacturing process, its automation degree is directly related to the processing technology and economic benefits.
Automatic tool changing system of NC machine tools is an important part of modern CNC systems, it is used to control the tool changing of machine tools. It can reduce tool changing time, improve the machining precision and reduce labor intensity. At present, the automation of NC machine tools has increasingly higher requirements, but there are still some problems in the products of automatic tool changing system. It is difficult to guarantee the accuracy of tool centres, the stability of tool changer, the state of tool head and the coordination in process. Therefore, to study the productization of automatic tool changing system of NC machine tools is an urgent issue for industry.
This paper mainly studies Automatic tool changing system for CNC machine tools and its productization.A comprehensive analysis of the application and development status of automatic tool-changing system for NC machine tools at home and abroad is done , and the optimal product design plan is put forward, so as to provide a technical support for further improvement of automatic tool changing system for NC machine tools.
2 Development Status of Automatic Tool Changing System for NC Machine Tools
2.1 Domestic Situation
At present, domestic CNC machine tools are gradually transitioning from simple manual control type to automatically controlled type and semi-automatic type, which has begun to focus on research and development of automatic tool changing system. Domestic research institutions, enterprises and universities have made great efforts in the research and development of tool changing system.
For example, active vibration isolation platform is a new type of automatic tool changing system developed by a research institute in Beijing. The external environment noise has a certain degree of influence on the dynamic characteristics of NC machine tools. The active vibration isolation platform has active vibration isolation performance, which can isolate external interference, avoid system fault and improve dynamic accuracy of NC machine tools.
2.2 International Situation
In developed countries, the use of automatic tool changing system for NC machine tools has a long history. Abroad, the research on the application and productization of automatic tool changing system for NC machine tools is very active.
For example, Siemens CNC System, with its interfaces to all major tools in the tool magazine and the possibility of optimized tool selection, has been widely adopted by many foreign machine tool manufacturers. This tool magazine can not only offer a variety of tools, but also provide tool length measuring device, so as to realize automatic tool changing of machine tools in an all-round way.
3 Design of Automatic Tool Changing System for CNC Machine Tools
3.1 System Design Requirements
(1)The automatic tool changing system should have high positioning accuracy to ensure the quality of machining parts;
(2)It should be reliable, ensuring that the tool changing process is repeated and guaranteed;
(3)The tool should be well sealed and shock-proof during transport to ensure the accuracy of the tool position;
(4)The system should be automatically adjusted and have a self-diagnostic function to ensure the system will work correctly and tell where the problem is;
(5)The size and weight of the automatic tool changing system should be minimized so as to save cost and reduce the damage to the machine;
(6)The system should be easily integrated into NC machine tools and require minimal configuration and wiring.
3.2 System Configuration
The automatic tool changing system of the CNC machine tools mainly includes: the tool changer, the tool mounting mechanism, the tool magazine, the tool recognition device, the tool setting device, the tool clamping device, the tool drive mechanism, the tool controller, and the system monitor.
The tool changer is generally composed of two parts: the internal tool changer and the external tool changer. The external tool changer is composed of a machine table, tool magazine, lifting platform and transmission parts. The internal tool changer is used to transfer the tools between the outside of the machine and the machine tool spindle, or from one side of the outside of the machine to the other, which is driven by a rotating disc.
The tool mounting mechanism is used for the loading, unloading and mounting of the tools. The tool magazine is usually a toolchain magazine with a small number of tools placed in it. The tool recognition device is mainly used to identify the tool identity and its position. The tool setting device is used to detect the error of the tool tip. The tool clamping device is used to drive the tool to the setting accuracy. The tool drive mechanism is used to drive the tool to rotate. The tool controller is used to monitor the tool delivery procedure.
3.3 Advantages and Disadvantages
The automatic tool changing system of CNC machine tools has the advantages of easy control, simple structure, fast tool change speed, high precision, small size and low cost. In addition, it does not require any external power, which is convenient for industrial production and can improve the production efficiency.
The disadvantage of the automatic tool changing system is that it is difficult to solve the problem of tool interference. In addition, when the tool number is large, if the tool magazine structure is not reasonable, the tool-changing time will increase, and the control system will become more complex, leading to a higher cost.
4 Conclusion
The automatic tool-changing system of CNC machine tools is an important tool-changing system in modern machine tools. Its realization has become a hot topic in the research of modern machine tools. This paper mainly analyses the application and productization of the automatic tool-changing system of CNC machine tools. The optimal product design plan is put forward, providing a basis for the further improvement of the automatic tool-changing system of CNC machine tools.
