 So, hello students, myself, Siddeshwar B. Tulsapure, Associate Professor, Department of Mechanical Engineering, Walshan Institute of Technology, Solapur. So, in this session, we are going to deal with the clamping circuit, the learning outcome. At the end of this session, students will be able to draw hydraulic clamping circuit and explain its working. The contents are, firstly, we will have the consideration of time and force. For the clamping operation, secondly, we will go for pump required for clamping operation. Then, we will go for the clamping circuit and its working. The lastly, the references are there. Now, let us talk about the time and the force for the clamping operation it is. Now, in case of the clamping operation, let us consider some machining operation, etcetera, like drilling or any milling operation, etcetera. So, in case of the, say, these operations, when these are to be performed, we are having some work piece or the job, which is to be loaded and unloaded and if it is loaded and then we are going for the clamping operation and then that particular process or operation we are going for, that is, either drilling operation we are going to do or, say, it is, say, that milling operation, etcetera, that is there. So, any other operation may also be there. So now, we are thinking of, say, the time required for that clamping operation and the force which is required during the clamping operation. Now, the thing is, when we are saying clamping operation, actually it is divided into the different sections. When it is first the approach for the clamping, in case of the, say, clamping, that plate it is, it has to come from a certain distance and that distance it is to be covered in a shorter duration. So, first approach for the clamping, it is there. So, first approach for the clamping, it is going to save the time. Then, say, first retract, say, it is for the declamping. In case of that, we are going to come across the declamping operation also. So, the plate it is, which is doing clamping operation, it is to be taken back again. So, then the job it is to be removed from the, that particular session and, say, one more job we are going to put. So, you can observe that fast approach and fast retract. These two are corresponding to the, say, unnecessary actions or you can say that, say, clamping will be the last thing, that is, once the approach distance is covered and then the plate it is stretching to the workpiece and then it is exerting the force on that one. So, in that case, only that clamping it is over now and, say, again, see if the plate is slightly away from the, that workpiece during the declamping. So, the job is declamped, but the, say, that plate it has to move again to the original position to have the space for the unloading of that particular job. So, now, the distances these are to be covered, say, these are going to be to some extent larger because the space required for the loading and unloading and for the movement of that hands of the worker, etcetera. So, it is going to be to some extent larger. So, now, when we want to cover that approach distance and the retract distance, so it should be covered in a faster manner. Then further, we come across the, say, clamping force, that is, say, the first one and the second one refer to the, say, distances covered means, say, velocity of the piston it is occurring. But the third one, you can observe that here no velocity of the piston is there. Further, piston is exerting the force on that job and that should be the higher. Means two parameters we are considering, one it is time and the second one it is the force. Time refers to the movement of that particular piston and force refers to the, say, standstill condition of that piston is there, but it has to exert the force on the workpiece. So, like that, two to different things we have to consider. Now we will think of the pump required for the clamping operation. See now, what we have to consider is fast approach for clamping, fast retract for clamping and these can be achieved how it is with the help of the large flow rate or discharge of the oil. Say, we are knowing that it is Q discharge is equal to, it is A into V. So, in case of that one, V it is going to be more, if Q is more, that is say we are in the need of high discharge pump it is, so that is what is need is. Then when the plate it is stretching that job and it is exerting the pressure or force on the workpiece, at that time no movement of the piston is there. So, in case of that one, we are in the requirement of a larger force for the clamping so that the job will not move. So in case of that say we are having say the high clamping force as a requirement and this can be achieved with the help of the high pressure pumps because the pumps these are going to develop the pressure and pressure it is going to act on the piston and then that piston it is going to exert the force. So one more you can have that is the cylinders with the larger diameter bore you can have also. So that is along with this one so but we are having the limitations to that one. So high pressure pump it is the requirement and high discharge pump it is the requirement so you can observe that to conflicting requirements we are having. So we can think of whether we can make use of the two pumps at a time. See it is one with low pressure and high discharge, second with high pressure and it is low discharge, two pumps at a time because the requirements these are conflicting low pressure high discharge and high pressure low discharge. See now the answer two pumps can be used at a time so this is called as the high low pump arrangement it is. So now how it is just we will go for now the clamping circuit and there are different components we are going to observe and we are going to observe how the working of that one is there and say whether the things which we have talked about we are able to achieve with the help of the circuit which we are say we have drawn here. See now we are having one reservoir here. So next to that one we are having the two pumps here one it is say developing 100 bar pressure and the second one it is there which is 50 bar pressure. In case of the pumps we should remember that say pumps they are say giving you the fluid energy that is in the form of it is rho g q h is there. So in case of this rho g that is density and it is say gravitational acceleration these are going to be constants say rho g q h we are having q it is discharge and it is the second one is the head pressure head so that is pressure. So pressure and discharge these two parameters these are going to come across and in case of this one so if the pump is developing more pressure so discharge it is going to be lesser. If the pump is developing lesser pressure discharge it is going to be say more. So we are having these two as exactly inverse to each other so that is this one will give you say higher pressure low discharge this one will give you lower pressure but higher discharge. But now you can observe that both these are run with the help of the same motor it is the motor is having coupling to this one also and this one also. So starting from the reservoir through the strainer the oil will go to the this pump also and this pump also. Next to that one say through the check valve it is going to come say further it is also going here see where it is going it is going to the unloading valve we will talk about it later and then say further the oil it is coming so on this side it is nothing but it is the relief valve is there. So relief valve it is normally closed unloading valve is also normally closed the oil will go to the through the check valve to the say P port P is connected to A in the present condition. So it goes to the cap end of the two cylinders and the pistons these are moving ahead and these are the surfaces which are going to exert the force on the workpiece two cylinders have been used because more force it is needed for the clamping. But now supply you can observe say the supply whether it is from this pump or this pump say 50 bar pump it is developing more discharge or giving more discharge and this one it is giving lesser discharge but these two are combined. So in case of this we are having the combined discharge here and then total discharge it is more because of that one the say fast approach will be there. Then afterwards when the plate it is touching that job it is exerting the pressure which needs to be higher. Then the discharge from the say 50 bar pump it is to be delivered to the say reservoir through the unloading valve. Unloading valves open at lower pressures than that of the pressure relief valves. So if the oil goes through the pressure relief valves say the wear and tear it will be more large amount of heat will be generated power consumption it is going to be more. So the excess oil it will be now delivered to the tank through the unloading valve and this say we are having the sufficient pressure which is maintained on the workpiece so that the clamping it is perfect. So in case of the say return stroke again when we are shifting the spool then we are having again supply to the rod end of these two cylinders and again the piston it is coming backward in a faster manner because at that time again the discharge from here 50 bar pump and the 100 bar pump both will be utilized and the pistons will come to this original position. So what we are having is discharge from 100 bar and 50 bar both will be taken initially for the approach distance to cover. Then we are having the clamping operation at that time 100 bar pump it is going to develop say that sufficient pressure on the job for the clamping and the discharge from the 50 bar pump it will be diverted to the tank through the unloading valve and again during the say withdrawal or you can say that the return stroke that is say declamping. So in case of this one again supply to the rod end is there but supply from both will be there and that one it is going to be also in a faster manner. So that is how we are going to make use of these two say pumps these are the references thank you.