 Hello friends, I am Mr. P. P. Mitra Guthri, Associate Professor in Department of Mechanical Engineering at Vulture Institute of Technology, Sholapur. In today's session, we are going to understand design of drawing die for a given component and in that also we are going to study only up to decision of number of draws required for a given component, because our drawing die design procedure will be lengthy which cannot be completed in one session, outcome for this session will be, students will be able to design a proper die set for a given component. Now next is, first of all we will understand what is a drawing and what is a drawing die. Drawing operation is carried out for manufacture of cup shaped components which are cylindrical or if we have to carry out a tapered cup, we can also suggest drawing operation. In drawing operation we are using a tensile force and we are using a punch and die set by which we can carry out forming operation and in this drawing operation you can observe that our sheet thickness is not an alter, not altered. We are only carrying out drawing into we are only carrying out physical change or change in the change in component in two dimensions that is very essential and for this particular component having 50 mm diameter and 45 mm height and corner radius of 1.6 mm we have to design a drawing die and this component is to be drawn in a material EMS having sheet thickness of 1 mm and yield stress given is 500 Newton per meter square. Now next part of design will be calculation of blank diameter for calculation of blank diameter we require to know the diameter of cup, height of cup to be drawn and corner radius and blank diameter capital D is decided by small d that is diameter of cup to be drawn divided by corner radius R. Now in our case diameter of cup to be drawn is 50 mm corner radius is 1.6 mm and 50 divided by 1.6 this ratio is much much greater than 20 as a result of which we are able to use the formula blank diameter is equal to square root of small d square plus 4 into small d into h where d is diameter of cup to be drawn h is height of cup to be drawn therefore blank diameter d is 50 square plus 4 into 50 into 45 mu that is square root of 11500 which comes out approximately to be 107 mm this is a theoretical blank diameter. Now the blank drawn has the edges to smoothen the edges and for that we have to carry out trimming operation that is cutting operation of the edges after drawing it is absolutely necessary otherwise our edges will be very sharp therefore every 3 mm per 3 mm per every 25 mm diameter of cup has to be added in theoretical blank diameter. Now our cup diameter is 50 mm therefore we have to add 107 mm plus 6 mm therefore our actual blank diameter has to be 113 mm that is 113 mm and we will refer actual blank diameter as a capital d now next step is calculation of percentage reduction required for drawing a cup no doubt we are drawing a cup from circular blank and this circular blank is to be transformed into cylindrical shell now our circular blank diameter is 113 mm and cup or shell diameter is 50 mm and this shell diameter outer diameter of the shell is 50 mm and inner diameter of shell is 50 mm minus 2 times the sheet thickness that is 48 mm so our percentage reduction calculation depends upon blank diameter cup diameter and we have to calculate it by the formula blank diameter minus cup diameter divided by blank diameter into 100 that is into percentage now blank diameter is 113 mm cup diameter is 50 mm therefore our percentage reduction required will be 113 minus 50 divided by 113 into 100 which will come out to be 63 divided by 113 into 100 which comes out to be 56 percent generally 45 percent reduction is permitted in the first draw not more than that 40 to 45 and in second draw around 30 to 35 percent reduction is possible or permitted in the second draw and our percentage reduction required is 56 percent it means that it clearly implies that to draw this cup in single draw is not at all possible because our percentage reduction is 50 is required is 56 percent therefore it is all confirmed that more than one number of draws are required to draw a cup in a given sketch in a given problem I think you are getting it next now I will pose you one question that is will you please tell me why percentage reduction in consecutive draws is reduced now we will calculate actual number of draws this required for that we have to decide a draw ratio draw ratio is h by d that is high top cup divided by diabetrop cup now there is empirical relation between number of draws and draw ratio if our draw ratio that is h by d ratio is up to 0.7 one draw is required if our draw ratio or h by d ratio is between 0.7 to 1.5 more than one draw and that is two draws are required and if our h by d ratio that is draw ratio is between 1.5 to 2 to 3 that is three draws are required and if our h by d ratio is 3 to 5 number of draws required will be 4 in our case height is 45 mm diameter is 50 mm so h by d ratio that is draw ratio is 0.9 so number of draws required for drawing the cup in our problem is confirmed to 2 that has been completely decided now references for further references for further reading I will ask you to read a book a textbook of production engineering by PC Sharma a book by Donaldson tool design named tool design and press tool design by indo german tool room avrangabad thank you