Abstract
In the recent years, the rapid development of Numerical Control Machine Tools (NCMT) has made it one of the most important and precise machining technology used in various manufacturing industries. The main purpose of the NCMT is to reduce the processing time, increase the machining accuracy, and make the machining processes more flexible. To achieve that, the control system plays a vital role in the successful application of NCMT. This paper presents an overview of the electrical control systems for NCMT. It starts with a brief introduction of the fundamental concepts of electrical control systems for NCMT followed by different components of the system. After that some case studies based on different application fields of the system were discussed in detail.
Introduction
NCMT are widely used in the manufacture of parts and components with highly accurate shapes and dimensions, used for vehicles, medical devices, turbines, engines, and many other applications. In theseApplications, high precision and control accuracy will be essential for achieving the desired results. The control system is an essential part of the NCMT, it is responsible for the operations of the NCMT, like the spindle speed, axial feed speed, machining tool motions, etc. The common types of control systems used in NCMT includes closed-loop control system, open-loop control system and Hybrid control systems.
Closed-Loop Control System
A closed-loop control system is also known as a feedback control system, which uses the feedback signals as an input to the controller and performs the necessary adjustments in order to ensure the desired outputs. The feedback signals received are compared to the setpoints of the program and the actuator output is adjusted to achieve the desired output. This system allows for the precision control of the NCMT, which is very important in many of the applications. Some of the popular closed-loop control systems for NCMT include Discrete Pulse Control (DPC) and Fuzzy Logic Control (FLC).
DPC is a type of closed-loop control system which uses a set of digital pulses as input to the system in order to perform the required control functions. DPC is essentially a digital control system that is simple to operate. It uses digital pulses to control the position of the spindles, axial feeds, etc., and in turn, it can ensure the precise control of these operations. FLC is another popular closed-loop control system which utilizes fuzzy logic algorithms to adjust the output of the system based on the feedback signals. It is often used in applications that require high accuracy and precise control.
Open-Loop Control System
An open-loop control system is a type of control system which does not use the feedback signals for controlling the operations of the NCMT. It inputs the required data from the user defined programs and based on the commands, it will output the desired commands which will in turn cause the NCMT to perform the desired operations. This type of control system is often used in highly automated machining operations that require high degree of accuracy and precision, such as the production of molds and dies. Some of the popular open-loop control systems for NCMT include Computer Numerical Control (CNC) and Direct Numerical Control (DNC).
CNC is a type of open-loop control system which takes input from a user-defined program and then outputs the corresponding commands to the NCMT. It is highly reliable and is used in automated machining operations that require high degree of precision, such as the production of molds and dies. DNC is another open-loop control system which is also used in automated machining operations. It utilizes a computer connected to the NCMT and provides the commands for the NCMT to perform the desired operations.
Hybrid Control System
A hybrid control system is a type of control system which uses both closed-loop and open-loop control systems together in order to achieve enhanced performance and accuracy. For example, a hybrid control system may utilize a closed-loop control system for controlling the spindle speed and an open-loop control system for controlling the axial feed. This type of control system allows for the precise control of operations and can also be used in highly automated machining operations. Some of the popular Hybrid control systems for NCMT include Direct Numerical Control with Pulse Control (DNC-PC) and Direct Numerical Control with Fuzzy Logic Control (DNC-FLC).
DNC-PC is a type of hybrid control system which utilizes both the digital pulses and the computer programmable controls to control the spindle speed, axial feed, etc. It is highly reliable and is used in highly automated machining operations that require high degree of accuracy and precision. DNC-FLC is another type of hybrid control system which utilizes both the fuzzy logic control and the computer programmable controls to control the NCMT operations.
Conclusion
Electric control systems are widely used in Numerical Control Machine Tools (NCMT) in order to achieve the accurate control of the operations. There are three main types of electric control systems for NCMT, namely closed loop control systems, open loop control systems and hybrid control systems. Each type of control system has its own advantages and disadvantages, and the selection of the most suitable control system for a particular application field depends on the requirements of the specific application.
In general, electric control systems have become an integral part of NCMT and they are playing an important role in the successful application of NCMT. Moreover, the development of new control systems and the improvement of existing ones will continue to provide more accurate and reliable control of operations in NCMT.
References
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