Design of C- Frame for Assembly of Mechanical Power Press

Size: px

Start display at page:

Download "Design of C- Frame for Assembly of Mechanical Power Press"

Augustus Curtis Barber
5 years ago
Views:

1 Design of C- Frame for Assembly of Mechanical Power Press H.N.Chauhan Assistant Professor Department of Mechanical Engineering Atmiya institute of Technology and Science, Rajkot R.G.Vaghela Assistant Professor Department of Mechanical Engineering Atmiya institute of Technology and Science, Rajkot A.L.dudhatra Assistant Professor Department of Mechanical Engineering Atmiya institute of Technology and Science, Rajkot Abstract The aim is to generate the model for assembly operation known as Mechanical press machine. Using the concept of reverse engineering the C-frame has been designed considering design specification, stress distribution, deflection. The objective of this study is to observe the finite element modeling of C frame of Mechanical power press of 50 ton capacity and to analyze the assembly of press under static condition. Press is made up of a frame, a base plate and a reciprocating piston which exerts force upon component through special tool mounted on the piston. The optimum resources possible in designing the Mechanical presses frame can effect reduction in the cost of the presses. By optimizing the weight of material utilized for the structure an attempt has been made in this direction to reduce the volume of material. So here we consider an industrial application project consisting of mass minimization of C-frame type assembly press so it can be check in the stress & then Material required & thickness of plate Keywords Analysis of Assembly Press; Modeling; Reduction in Material Weight; Analysis in Static Condition) INTODUCTION The function of a press is to transfer one or more forces and movements to a tool or die with the purpose of forming or blanking a work piece. Press design calls for special knowledge of the production process to be used. Depending on the intended application, the press is designed either to execute a specific process or for mainly universal use. In a specialized production line, in view of economic production, the output is the most important issue, while maintaining the required part quality. Material-related influences such as the maximum deep drawing speed or work piece-related influences such as the suitability of parts for transportation, as well as aspects such as operating ergonomics and working safety all have to be taken into consideration Press Frame The function of the press frame is to absorb forces, to provide a precise slide guidance and to support the drive system and other auxiliary units. The structural design of the frame depends on the pressing force. o This determines the required rigidity, o the dimensions of dies influencing the size of the tool area, o work area accessibility that determines on the shape of the press frame, o The degree of guidance precision. This influences both the shape and the rigidity of the frame.presses with relatively low press forces, up to 2,500 kn, frequently make use of the open-front press design This construction is characterized particularly by the easy access to the tool area. However,its rawback lies in the asymmetrical deflection of the frame, which contributes to reductions in part accuracy and die life, particularly in blanking applications. Inclined or horizontal designs permit faster

2 part Rejection making use of gravity following the forming process, for example when forging or coining open-front presses mare used in conjunction with single dies Applications In its modern form hydraulic press is well adapted to press work of Forging presses Stamping machines Rolling presses Riveting machines Blanking and punching machines Structure Depending on application different frame structures are available while performing the operation 1. 'H' TYPE OR fabricated 4-column type 2. 'C' type 3. 4-pillars (Hard chrome pillars type) C- frame presses These presses have a 'C' like shape, which is specifically designed to maximize the floor space for the workers in order to move around easily at the workplace. Unlike other presses that have multi-processes, the C- frame presses only include a single press application. Its application includes straightening, drawing and mostly includes assembling work. C-frame presses come in a variety of weights. The C- frame presses are also available with extra features such as wheel stands and pressure gauges. Need of the Project: The operation of assembly was initially carried out by hand operated power press. & this operation required more manpower & good Inspection. To reduce the human error & fast production Mechanical Power press was taken into consideration. The C frame was considered for support of the press as standard C-frame presses are precise and easy to control to most pressroom applications including punching, blanking, coining, forming, bending, drawing and assembly work. The C frame press is considered because of its high rigid frame construction and also the maintenance cost of the press is less compared to other. In most of the presses there are some waste materials where no stress is acting there. This increases the material weight and cost. So these materials should be removed to reduce the material usage to increase the profit and reduce wastage. Methodology The dimensions and specifications for a C-frame assembly press are provided by manufacturer. Using the specifications and dimensions a C framed assembly press. As per the specifications the load is applied on the frame and the deflections and stresses acting on the structure are calculated. The design of the frame is further modified to reduce material required without compromising the design specifications. The objective is to make use of minimum available resources, to maximize profit without affecting the quality, durability, operation of the system. Design Specifications Outer diameter of the Ram - 55mm Inner diameter of the Ram - 45mm Stroke Length - 260mm

3 Design Check for Top Plate INPUT DATA Outer diameter of piston rod = 55mm Inner diameter of piston rod = 45mm Material selection: Designation Yield Strength Tensile Strength (N/mm 2 ) (N/mm 2 ) EN Direct Tensile or Compressive stress due to an axial load:- fc act = W A fcact = 50X 10 3 fc act = N/mm 2 fc all = π/4( ) fc all = fc all = Piston rod is safe in compression Hence material selected is Mild Steel. Material used : Mild Steel Young s Modulus : N/mm2 Poisson s Ratio : 0.3 Density : 7860Kg/meters cube Thermal expansion : Checking for the deflection Deflection along the axis of application of force at A and B at the extreme end.

4 frame of press for Radius of Gyration R = Radius of gyration. H = R φ φ =......(1) H + δ = R 1 φ φ =..(2) Where R 1 = R + a + L Equating both the equation = δ = In order to determine the increase in throat height i.e. δ, it is consider that the natural axis bends under the load P to consider arc of radius R. In unloaded condition the natural axis does t bends and in loaded condition the angle of inclination become φ. Now, = = R = Here, Mb = x 10 6 Nmm I xx = x 10 6 mm 4 E = 2.1 x 10 5 N/mm 2

5 R = R = 2.80 x 10 6 δ = δ = δ = mm. Where H= 1220 mm. L= 270 mm. a= 585 mm. R= 2.80 x 10 6 mm The maximum deflection at the extreme end B. = = δ max = mm. Component List Sr No COMPONENTS DIMENSIONS 1 Bottom Plates 180*180*10 2 Supporting Plates 350*10*10 3 Fixture Plate 150*8*8 4 Base Plate 2 550*300*10 5 Base Plate 1 550*450*10 6 Top Plate 550*150*10 7 Rib 2 150*100*8 8 Rib 1 180*130*8 9 C Channel 100*50*5 Hydraulic Circuit The counter balance valve is used. This a pressure control valve. Counterbalance or backpressure is used to keep the vertically mounted hydraulic cylinder in upward position while pump is idling. It prevents the vertical cylinder from descending due to weight of its load.

of Nodes : 52924 Validation of deformation and Stress calculation Effect of plate thickness on

6 Analysis Effect of Plate Thickness on Deformation Effect of Plate Thickness on Stress Mesh Independency Mesh Size : 0.05 No. of Elements : 7936 No. of Nodes : Validation of deformation and Stress calculation Effect of plate thickness on Deformation Plate Thickness Analytical Practical Difference (mm) (mm) 20mm mm mm mm

7 CONCLUSION In this project the Assembly Press is studied and the design of the C frame is done as per the requirements by following the process of Reverse engineering. The modeling of the C frame will do in software. The analysis of the assembly press is carried out using. Design was done for the C frame by reducing its material used, without causing wastage of material. The positions where the stresses were not acting the extra material was removed thus optimizing the design without compromising. The result obtained from analysis software is within the limit. REFERENCES 1. Fluid Power with applications by Anthony Esposito VI edition 2. Psg design data book, DPV printers, Reprinted May Design of Machine Elements (THIRD EDITION Modal Publications) V.B.Bhandari 4. Analysis of Hydraulic Press Frames for Open Die Forging Martin Zahalka* International Symposium on Intelligent Manufacturing and Automation, Ibrahim Zeid and R. Sivasubramanian, (2010), CAD/CAM Theory and Practice, By, McGraw Hill 6. L. S. Gupta and P. U. Ramanamurti, (1982) Stress analysis of 400-tonne hydraulic press cross- head. Proc. AZMTDR Co, pp A Course in Machine Design by K. K. Pujara & B.L. Juneja, Dhanpat Rai & Sons Publication, New Delhi. pg

FINITE ELEMENT ANALYSIS OF A 2.5 TONNE HYDRAULIC PUNCHING MACHINE

FINITE ELEMENT ANALYSIS OF A 2.5 TONNE HYDRAULIC PUNCHING MACHINE Nikhil Mahajan 1, Prof. S. B. Tuljapure 2 1 M.E. Scholar, 2 Assistant Professor Mechanical Engineering Department Walchand Institute of