 Hello friends, I am Naval Yamal working as Assistant Professor in Mechanical Engineering Department at Walchin Institute of Technology, Solapur. In this video, we are going to see CNC power programming, learning outcome. At the end of this session, students will be able to understand power programming of CNC machines. Objectives to understand the dimension system in CNC power programming. To understand the structure of the CNC power program. Content. We are going to cover first axis of motion, then dimension systems, definition of the programming and program structure. I am going to see the explanation of the words which we use in program structure. First, axis of motion. In general, all motions have six degrees of freedom. In other words, motions can be resolved into six axes, namely three linear axes. Those are x, y and z and three rotational axes A, B and C. These are shown in the figure one. As we can see, there are three axes x, y and z and those three axes can be rotational also and that rotational are denoted as A, B and C. So in total, there are six degrees of freedom for axis of motion. Second, dimensional, dimension systems. In dimension system, there are two types. One is incremental system, another is absolute system. First, we are going to see incremental system. Type of control always uses as a reference to the preceding point in the sequence of points. The disadvantage of this system is that if an error occurs, it will be accumulated. For example, if you want to do a machining, the reference point is always from the preceding point and not always from the origin point. So this type of dimension system is called incremental system. Second is absolute system. In an absolute system, all references are made to the origin of the coordinate system. All commands of motion are defined by the absolute coordinate referred to the origin. So as we can see in the figure number three, there is absolute system where the reference is always made from the origin. Third definition of the programming. Numerical control programming is where all the machining data are compiled and where the data are translated into a language which can be understood by a control system of the machine tool. The machining data is as follows. The machining sequence classification of process, tool startup point, cutting depth, tool path, etc. Cutting conditions like spindle speed, feed rate, coolant, etc. Selection of cutting tools. Fourth program structure. Numerical control program consists of blocks, words, and addresses. As shown in the figure four, the structure of CNC part program. The first consists of block one, then block two, and so on till block 30 and block 31. In one block, as shown in the figure, it consists of sequence number then followed by the word one and followed by the word two. For example, it is shown as N002G01. These are explained in the next slides in detail. These program structure consists of blocks, words, and addresses. First we are going to see what is block. A block is nothing but a command given to control unit is called a block. When you see word, a block is composed of one or more words. A word is composed of an identification letter and a series of numerals. For example, the command for the feed rate 200 mm per minute is given as F200. Third is address. The identification letter at the beginning of each word is called address. The meaning of the address is in accordance with electronic industries association, that is EIA standards. RS274D, the most common addresses are listed in the next slide. These are the most common addresses, function and address. Sequence number is given as N, preparatory function is given as G, coordinate word is given as X, Y and Z. Parameters for circulation interpolation, I, J, K, feed function F, spindle function S, tool function T, miscellaneous function M. So we are going to see what are sequence number and preparatory function in the explanation of words. In sequence number also called as N addresses, a sequence number is used to identify the block. It is always placed at the beginning of the block and can be regulated and can be regarded as the name of the block. The sequence numbers need not to be conjugated. The execution sequence of the program is according to the actual sequence of the block and not the sequence of the number. In fact, some CNC systems do not require sequence numbers. Second preparatory function, those are G addresses. A preparatory function determines how the tool is to move to the programmed target. The most common G addresses are listed in the next slide. Note down some of the G addresses which you know. So the next slide we will see the G addresses. Code and function, G00, the function is point to point position at rapid feed. G01, the function will be in linear interpolation. G02 is circular interpolation clockwise. G03, circular interpolation anticlockwise. G40, cutter compensation cancel. G41, cutter compensation left. G42, cutter compensation right. And from G70 to G79, those are milling and turning operations perform. And G80 to G89, drilling and tapping cycle operations. G90 is absolute dimensions which we have seen. G91 is incremental dimensions. So these are basic and main addresses which we use in the CNC part program. So third is coordinate word that is x, y, z and addresses. A coordinate word specifies the target point of the tool movement is absolute dimension system or the distance to be moved that can be incremental dimension. The word is composed of the addresses of the axis to be moved and the value and the direction of the movement. For example, x100, y200 represents the movement to 100, 200 coordinate where the dimensions are absolute or it can be incremental will have to be defined previously using G90 or G91. G90 is for absolute address and G91 is for incremental. And the fourth point we're going to see the steps for the CNC programming and machining. The following is the procedure to be followed in the CNC programming and machining. The most important points is to verify the program by test run it on the machine before the actual machining in order to ensure that program is free of mistakes. The first step is to study the part drawing carefully. Unless the drawing dimensions are CNC adapted, select a suitable program, zero point on the work piece. The tool will be adjusted to this zero point during the machine setup. Determine the machining operations and the sequence. Then determine the method of work that is clamp, vice, rotary table or fixtures, etc. Select cutting tools and determine spindle speeds and feeds. Right program, that is translate machining steps into program blocks. If any solutions are possible, try the simplest solution first. It is usually longer but better to proceed in this way. Prepare tool chart or diagram, major tool geometry, length radius and noted. Clamp work piece and setup machine. Enter compensation values if necessary. Check and test program. It is a good practice to dry run the program without the work piece, without the cutting tool or by raising the cutting tool to the safe height. If necessary correct and edit program and check again. And then start machining. These are the references which I have used for this video. Thank you.