CNC Full Form in Hindi| Computer numerical control (CNC)

CNC ka फुल फॉर्म Computerized Numerical Control hota है. इसको हिंदी मे संख्यात्मक नियंत्रण कहते है

LED Full Form in Hindi| What is an LED?

David Essex

Computer numerical control (CNC), which is software embedded in a microcomputer attached directly to a tool, automates the control of machine tools. It is used to machine metal and plastic parts.

With CNC, each object to be manufactured gets a custom computer program, usually written in an international standard language called G-code, stored in and executed by the machine control unit (MCU), a microcomputer attached to the machine. This program specifies the parameters and instructions that the machine tool will use, including the material feed rate and the speed and positioning of the components. Common machine tools that can be automated using CNC include mills, routers grinders, lasers, and routers. It can also be used for controlling non-machine tools such as welding and electronic assembly, or filament-winding.

Early in the process, engineers create a computer-aided design (CAD) drawing of the part to be manufactured, then translate the drawing into G-code. To ensure that the program works properly, a human operator runs a test run on the MCU without the raw material. This is crucial because an incorrect speed or position can cause damage to both the machine as well as the part.

CNC is thought to offer greater precision, complexity, and repeatability than manual machining. There are other benefits, such as greater precision, speed, and flexibility. Also, contour machining allows for the milling of contoured forms, even those created in 3D models. However, CNC is more costly and requires more maintenance than other production methods. This makes it necessary for companies to employ a CNC programmer.

See also  What Is The Full Form OF IMA

Some CNC systems are integrated with CAD and computer-aided manufacturing (CAM) software, which can speed the process of programming the MCU. Integration with ERP software and other related applications such as enterprise asset manager software can speed up operational intelligence and improve plant performance.

Motor drives are required to control the position and velocity of CNC axes. Each axis needs to be driven independently and must obey the command signals generated by the numerical controller. There are two methods to activate servo drives: the open-loop and closed-loop systems.

An input device is used to feed programmed instructions into an open-loop CNC controller. The controller converts these instructions to electrical signals and sends them to the servo amplifier for driving the servomotors. The distance each servo drive moves is determined by the cumulative number of electrical pulses. The signal frequency determines its velocity. Open-loop systems have one primary feature: there is no feedback system that can check if the desired velocity and position has been reached. If system performance has been affected by load, temperature, humidity, or lubrication, then the actual output could deviate from that desired. Open-loop CNC systems are generally used for point-to-point systems, where accuracy is not important. Open-loop control is rarely used in continuous-path systems. Figure 2.2 shows the control mechanism for an open-loop CNC machine.

A feedback subsystem is part of the closed-loop CNC system. It monitors the output and corrects any deviation from the program. This feedback subsystem can be analog or digital. Analog systems measure variations in physical variables such as velocity and position as voltages. Digital systems monitor the output variations using electrical pulses. Closed-loop systems can be very accurate and powerful because they are able to monitor operating conditions via feedback subsystems. They can also compensate for variations in real time. Modern closed-loop CNC systems can provide a very precise resolution of 0.0001 inches. Closed-looped systems will require more control devices and circuitry to achieve velocity and position control. They are more complicated and more costly than open-loop systems. Figure 2.3 shows a closed-loop CNC system.

See also  cpu full form| What does CPU mean?

H.Y. Zheng, … S.M. Yuan, in Printing on Polymers, 2016

Conventional CNC micromachining

Conventional CNC micromachining can be done on a 3-axis CNC milling machine, or multiaxis CNC center. The accuracy and resolution of these machine tools is often in the micrometer or submicron range. A new high speed milling strategy has been developed for large brass foil master moulds, as illustrated in Figure 10.22. It uses a custom single-crystalline diamond endmill attached to a three-axis CNC high speed milling machine (Liu Wu, Shaw, 2013). The brass foil measures 0.35 x 1.5 mm in size and has a thickness of 200 mm. Its machining area is 300×500 mm. Figure 10.23 shows the machined brass foil with microprism array: (a) overview and (b) close-up view, where the pitch of the prism array is 400 +- 10 mm, the sag size is 79 +- 1 mm, and the prism angle is 60deg. The average surface roughness is 60 nm in Ra. Figure 10.23 shows how the machined brass foil mold can wrap around a roll so that it can be used directly for roll-to–roll (R2R), printing microprism array structures on polymer films.

Xizhi Sun, Kai Cheng, in Micromanufacturing Engineering and Technology (Second Edition), 2015

Control system

Many companies began to develop control systems for their machine tools after the invention of Computer Numerical Control (CNC), in the early 1970s. The control system usually includes the motors, amplifiers and switches as well as the controller. The high-speed multiaxis CNC controllers are essential for precise and efficient control of servo drive, error compensation (thermal or geometrical errors), optimized tool set up, and direct entry into the equation of shapes. Advanced PC-based control systems have achieved nanometer or even subnanometer levels of control resolution for ultraprecision and micro-manufacturing purposes, such systems also being used commonly in the majority of commercially available ultraprecision machines.

See also  MP की फुल फॉर्म क्या होती है? What is the full form of MP?

Leave a Comment

Your email address will not be published. Required fields are marked *