 Hello students, this is Mr. Nagesh R. Tambake, Assistant Professor, Department of Mechanical Engineering, Walton Institute of Technology, Sholapuram. Today we will discuss on Introduction to CNC Machine Tool, Learning Outcome. At the end of this session, students will be able to explain CNC machine tools. In this particular session, we are going to discuss introduction. Why is CNC machining necessary? Working of CNC machine, advantages of CNC systems, disadvantages of CNC systems, applications of CNC machine tools, and when to use CNC machines. Now first of all, I will ask the question to you. What is a NC machine? That is numerical control machine. Please think on it and try to get the answer. Machine control is a programmable automation in which process is controlled by numbers, letters and symbols. CNC machining is a process used in the manufacturing sector that involves the use of computers to control machine tools like leads, mix and grinders. Why is CNC machining is necessary? To manufacture complex curved geometries in 2D or 3D was extremely expensive by mechanical means, which usually would require complex jigs to control the cutter motions. Machining components with high repeatability and precision, unmanned machining operations. To improve production planning and to increase productivity. To survive in global market, CNC machines are must to achieve close tolerances. Now we will see the working of CNC machine, how it works. The components of this particular machine is input device, machine control unit, then display unit, driving system, machine tool and feedbacks device. The program is input into the MCU and the data is converted into motion commands at MCU. The MCU sends these motion commands to the driving systems. The drive system follows the commands given and manage the motion and velocity of the machine tool. Some CNC machines operate with the aid of feedback devices, others do not. Without feedback, the tools may overshoot or may not reach the desired position because of inertia, wear and tear and friction. To achieve higher accuracy and repeatability, sensors measure the position and velocity and feed these data back to the MCU. These feedback signals are compared with the reference signals in the MCU and if there are errors, new commands are sent to the machine tools to compensate for these errors. The operator can see all the commands, programs and others important data at the display unit. Likewise, the CNC machine works. Now we will see the advantages of CNC systems. CNC machines can be used continuously and only need to be switched off for occasional maintenance. These machines require less skilled people to operate unlike manual lathe or milling machines etc. CNC machines can be updated by improving the software used to drive the machines. Manufacturing for the use of CNC machines can be done through the use of virtual software. The manufacturing process can be simulated virtually and no need to make a prototype or a model. This saves time and money. Once programmed, these machines can be lifted and do not require any human intervention except for work loading and unloading. These machines can manufacture several components to the required accuracy without any fatigue as in the case of manually operated machines. Savings in time that could be achieved with the CNC machine are quite significant. We can save the time by using these particular CNC machines that is the very much popular advantage of CNC machines over conventional machines. Now disadvantages of CNC systems. CNC machines are generally more expensive than manually operated machines. The CNC machines operator only needs basic training and skills enough to supervise several machines. Increase in electrical maintenance, high initial investment and high per hour operating costs than the traditional systems. Fever workers are required to operate CNC machines compared to manually operated machines. Investment in CNC machines can lead to unemployment. Now applications of CNC machine tools. CNC was initially applied to metal working machinery likewise in mills, in drills, in boring machines, in punch and presses etc. Now expanded to robotics, grinders, welding machinery, mediums that is electro discharge machining, flame cutters and also for inspection equipment etc. Now usually the parts made on CNC machines are aerospace equipment are there, automobile parts are there, complex shapes are there. Electronic industry uses CNC for printing circuit boards. Electronic industry uses CNC for making winding of the coil. Now when to use CNC machines? That is one of the question because what will happen? CNC machines are very much costly therefore single part you cannot manufacture in a CNC machine. Here you have a mass production, batch production that time CNC machine is affordable and also in certain cases that cases now we will discuss upon. Now for small to medium batch quantity that time we can use the CNC machine. For parts subjected to regulatory design changes, if you want to make certain changes in the design that time we can make the changes, design changes in the program and that we can apply to the machine and definitely we will get the required object, whatever the design changes that we made that we can get at the part. When the inspection is required 100% whenever inspection is made 100% that to the parts are required in the defense sector in the aerospace industry. In that case we need to go for CNC only where we will get the required parts because the machine is totally programmed and there are less chances to occur a failure. When lead time does not permit the conventional tooling manufacture that time also we can use a CNC machine. When the machining time is very less as compared to downtime. If machining if any customer is there if he is coming towards us and he requires a mass production of certain job that time if we are trying to do that particular job on a conventional machine that time we cannot supply him the certain parts in the required time therefore definitely we need to go for a CNC machine so that we can complete the order in the required time where the repetitive operations are required on the work. If suppose I need to make a repetition of one object for 1000 products then definitely I need to go for a CNC machine these are the references thank you.