Lecture on.8 Introduction to Numerical Control Systems

Hello friends, I'm professor Vidyadarshan Sagar. Today we are going to see lecture number 8 on introduction of numerical control production system. Next topic of this particular unit is computer numerical control machines that is CNC machines. This is the next evolutionary stage as we have seen in previous lecture. So computer numerical control machine that is CNC machine is used to perform all basic functions which is performed in NC machines. To control the machine tool this type of system is called NC machine. The program can be stored in computer memory and retrieve whenever it required. Some important features available in CNC machines as follow. The part program can be input to the controller unit with the keyboard very easily. The part program can stored in memory and use again and again. The part program can change and optimize according to the design of product. Specially sub programs can be used from the library we can create in the CNC machine controller. It having facility to see the simulation on screen without actual running on the machine. It provide compensation for the change in dimension of the product design. It provide management information function such as component produce time for the setting of the job etc. The diagram you can see that here the basic components of numerical computer numerical control machine can be integrated with the medium of the program reader then the NC program storage then the mainframe computer and the computer buffer memory. So these are the main component of the CNC machine. Now the next evolutionary stage of the numerical control machine is a direct numerical control machine or we called as a DNC machine. It is a new generation manufacturing system in which a large number of machines are controlled by master computer through direct connection or through the satellite. In it all machines are linked with the mainframe master computer directly or indirectly configured as follows. It having two main configurations mainframe computer connected the machine directly or mainframe computer connect to each machine with the mini computers even at a longer distance through the satellite computer. So it having a basic typical DNC machine shown in our diagram. The controller unit of a computer bulk memory which is connected with the different mini computers of different machine tool. Then type of direct numerical control machines behind the tape reader system special machine control unit behind the tape readers it is linked directly to the regular NC controller unit with telecommunication link is called a behind the tape reader or BTR system. It is used to temporary storage buffer to receive the block of instruction from DNC computer one for receiving other in giving the command. The DNC computer attached with the bulk memory of NC program and the controller is constantly taking the feedback and giving the instruction to the DNC computer and the DNC computer is connected with the machine tool. Now the direct numerical control machine configuration in it the DNC to eliminate the regular NC control and replace it the special machine control unit. It is important in case of communicating the circular interpolation of the cutting part it achieves a superior balance between the accuracy of the interpolation and the pass metal removal rate. Next topic is application of numerical control machines. There are a number of numerical control machine tools are available in market and industry. Machine tool applications such as drilling operation, milling operation, turning operation and other metal working operation can perform with the help of numerical control machines. Application again like non machine tool application like assembly drafting and inspection also can be performed with the help of numerical control machines. Now it having some advantages of numerical control machines like first reduce lead time as we all know that as we are eliminating the manual operations from the industry we can easily minimize the lead time or the wastage time. Eliminate the error of operator obviously when we eliminate the manual efforts from the manufacturing shop floor we can easily eliminate the error of operators. Increase operators activity operators activity get increase in form of programming, in form of inspection, in form of maintenance. Lower labor cost obviously the labor get reduced due to the automation implementation of numerical control system so lesser manpower will be required. If the lesser manpower will be required obviously a low labor cost reflected at the end of the balance sheet of industry. Then the smaller batch size so number of products can be many number of design of products we can manufacture number of design of batch of products we can manufacture in a single shop floor that means it reduce the batch size effectively efficiently. A longer tool life due to the reduce in wastage of time wastage of material we can obviously reduce the tool life also we can longer the tool life easily. Then eliminate of special jigs and fixture in case of numerical control machine there are number of fixtures and jigs are settings are available due to which fixtures and jigs arrangement that we required in conventional type of systems can easily eliminate. Then flexibility in change of component of design we can easily change the design for every instance of time because it having a flexibility to adopt for any type of design change due to the numerical control system is running on a soft programs or hard medium program. Then reduce the inspection we need not to inspect instantly during the in process of the manufacturing processes. Then less scrap get generated due to repeatability in highest accuracy of manufacturing processes less scrap get generated and due to which the raw material can save or optimally utilized for manufacturing of the finished product. Then accurate costing and scheduling can be done with the help of numerical control machine in which we can easily identify how much time will be required. We can prepare the master schedule we can prepare the requirement and capacity planning. Then reduce non-production time by mean of fewer setup and reduce work piece handling in time. So these are all are the advantages of NC machines. Now some disadvantages are also there but it are these are very less as compared to the advantages. Disadvantages like higher investment at the beginning then higher maintenance cost then costlier CNC personnel because CNC personnel are very less in number available who having good experience in the particular expertise area. So they demands higher salaries and wages. Then the disadvantage is plant support facility. Plant support facility is very weak as compared to the NC machine because this NC machine technology is nowadays new and very less people know about it. So the plant support facility is very less available in NC machine. So thank you very much for today's lecture.