 Hello friends, I am Naval Emul working as an assistant professor in Mechanical Engineering department at Vulture Institute of Technology, Sholapur. In this video, we are going to see the fundamentals of CNC machine part one. Learning outcome, at the end of this session, students will be able to understand fundamentals of CNC machine objectives. Students will be able to understand the working principle of CNC machine, to understand the characteristics of driving systems, to understand the characteristics of feedback devices, to understand the applications of CNC machine, content, introduction of CNC, control system, elements of the CNC system and references, introduction. The definition of the CNC given by the Electronic Industry Association that is IEIA is as follows. A system in which actions are controlled by the direct insertion of numerical data at some point, the system must automatically interpret at least some portion of this data. In simple word, a CNC system receives numerical data, interpret the data and then control the action accordingly. Control open loop systems, open loop systems have no access to the real time data about the performance of the system and therefore no immediate corrective actions can be taken in case of the system disturbance. This system is normally applied only to the case where the output is almost constant and predictable. Therefore, an open loop system is unlikely to be used to control machine tools since the cutting force and the loading of the machine tool is never a constant. So in figure number one shows a block diagram of the open loop system. In figure it shows the input to the system and output from the system but there is no feedback from output to input. Next we will see closed loop system. In a closed loop system feedback devices closely monitor the output and any disturbances will be corrected in the first instance. Therefore high system accuracy is achievable. The system is more powerful than the open loop system and can be applied to the case where the output is subjected to frequent change. Nowadays almost all CNC machine use this control system. So the input is given to the system and we get the output from the system but output is measured or output is monitored closely and then the feedback is sent to the input. This all is shown in the figure number two, the block diagram of the closed loop system. Elements of the CNC system. A CNC system consists of the following six major elements. First is input devices, second machine control unit, machine tool, driving system, feedback devices and display unit. In this video that is fundamental of CNC part one only the major element of input device is explained in detail and all five are explained in the next video that is fundamental of CNC part two. So here you get a figure number three where working principles of the CNC machine are explained in detail. The input device will go into study in detail of input devices. In input device you get a part program those signals are sent to the machine control unit and machine control unit again the signals are sent to the machine tool or driving systems. From the machine tool you get certain operations performed on the machine tool and the feedback is again sent back to the machine control unit. If there are any corrective measures the corrective measures are taken and again the signals are sent to the machine tool for the further operations. The feedback devices consist of two types that is position feedback and velocity feedback. These are clearly explained in the next video that is fundamentals of CNC part two. So there are basic six major components in CNC that is input device, machine control unit, machine tool, driving system, feedback device and then display unit. So we will see one by one. So first input devices, input devices first is plopid disk drive. In late 1970s the plopid disk drive was using majorly in terms of data transfer speed reliability storage size data handling and the ability to read and write. It was a common storage media but nowadays they are using they are not using the plopid disk drive. In figure four shows the plopid disk drive of the CNC machine. Second USB flash drive, a USB flash drive is a removable removable and rewriteable portable art drive with compact size and bigger storage size than a plopid disk. In recent years all computers support USB flash drives to read and write data that make it become more and more popular in CNC machine control unit. Third is serial communication. The data transfer between a computer and the CNC machine tool is often accomplished through a serial communication port. International standards for serial communications are established so that information can be exchanged in any in an orderly way. So in figure five shows the serial communication port on a CNC machine. The most common interface between computers and CNC machine tool is referred to the EIA standards that is RS232. Most of the personal computers and CNC machine tools have built in RS232 port and the standards RS232 cable is used to connect a CNC machine to a computer which enables the data transfer in reliable way. The part programs can be downloaded in a memory of a machine tool and uploaded to a computer for temporary storage by running a communication program on a computer and setting up a machine control to interact with the communication software. CNC machines are also called direct numerical control is referred to the system connecting a set of numerically controlled machines to a common memory for part program or machine program storage with provisions for on-demand distribution of data to the machines. Distributor numerical control is a hierarchical system for distributing data between a production management computer and numerical control system. The host computer is linked with a number of CNC machines or computers connecting to the CNC machine for downloading part programming. The communication program is in the host computer can utilize in two ways that is by production data communication and production schedule and part produced and the machine utilization etc. So here is a figure which shows the serial communication which is linked in a distributed numerical control system. There is one single host computer which controls all other four CNC machines. So the work order from the production control system it comes to the host computer. This host computer controls all other four CNC machines. So this type of input device are called a serial communication in a distributed numerical control system. The four type in input device is Ethernet communication due to the advancement of the computer technology and the drastic reduction in the cost of the computer it is becoming more practical and economic to transfer part programs between computers and CNC machines via an Ethernet communication cable. This media provides a more efficient and reliable means in part program transmission and storage. Most companies now build a local area network that is LAN and their infrastructure. More and more CNC machine tools provide an option of this Ethernet card for direct communication with the LAN. Here we have a host computer which is controlling all other CNC machines with the help of local area network that is LAN. Lastly we have a conservational programming. Part programs can be input to the controller via the keyboard built in intelligent software inside the controller enables the operator to enter the required data step by step. This is a very efficient way for the preparing programs for relatively simple work pieces involving up to two and a half access machines. So I will give you a few seconds to note down all the major elements of the CNC. So let's have a quick revision of all the major elements of the CNC. First was input devices, second is machine control unit, third is machine tool, fourth is driving system, feedback devices and the last is display unit. These five points will be covered in the next video that is fundamentals of the CNC part 2. These are the references I have used. Thank you.