CHAPTER-1INTRODUCTION1.1 Introduction To Sheet Metal Cutting Operations:Sheet metal forming, also called stamping, involves operations such as cutting, drawing etc on sheets. Sheet metal forming mostly involves tensile forces, compared to bulk forming, which involve compressive forces.
Due to tensile stress, sheets may undergo deformation followed by cracking. Sheets are rolled products, which have thickness less than 6mm. Sheet metal operations involve w/p with large surface area to thickness ratio. Blanks are cut from sheets. These blanks are continuously subjected to one or more sheet forming operations in order to get the finished component. Sheet metal forming is widely used for producing wide range of products starting from household vessels to aerospace parts, to automobile or aircraft bodies.
Final shape is obtained by applying tensile, shear or combination of forces.Hydraulic or mechanical presses which are also called as stamping presses are used for the forming process. Die – punch combination is used for the process to apply the desired shape to the blank. Dies may be simple or compound, which include several operations. Transfer dies can be used in heavy operations.
Mainly tensile force is used in the sheet metal operation.However, reduction in sheet thickness is avoided in sheet forming, due to localized deformation called necking.Many Manufacturing Industries forming operations are carried out manually using jigs and fixtures or by means of a machine. These machines could be Mechanically, Pneumatically or hydraulically operated.
These machines are costlier to manufacture, Installation and for maintenance also. Along with these,the running cost of these types of Machines are also very much high. An electromagnetically operated forming machine proves itself better against these machines in respect with above said points.CHAPTER-2Electromagnetic Sheet Metal Operations Machine2.1 Historical Background:The phenomenon, that a force is exerted on a current carrying conductor when placed in a certain direction in an electromagnetic field or, when placed close to another current carrying conductor has been known for a very long time. It was in the Twenties when attempts where made to use these forces to stress metals beyond their yield strengths and therefore to deform them permanently. However, to generate forces or electromagnetic pressures which exceeded the yield strengths of common industrial metals, electric currents and electromagnetic fields in the magnitude of several hundred kilo-Amperes and kilo-Gauss were needed.The experimenters in the Twenties tried short circuiting large rotating generators.
It was hoped that the kinetic energy of the rotating machines could be used to produce the required high currents. These attempts failed because of various technical problemsIn the early 1960’s, General Atomic in San Diego, while conducting nuclear fusion research, experienced material failures caused by the forces between current carrying conductors. The extremely high temperatures required for fusion research were produced by compressing an ionized gas with a high-intensity electromagnetic field. The currents required to generate the high-intensity fields were produced by discharging many paralle lconnected capacitors into a coil. Parallel copper bus bars were used to carry the capacitor currents to the coil. These currents could reach magnitudes from several hundred thousands up to around one million Amperes.
Someone then had the idea of using these “undesired” forces to perform useful work. The bus bar system was transformed into a coil into which an electrical conductive 3 4 th International Conference on High Speed Forming – 2010 work piece would be inserted. The interaction of the field and induced current would exert pressure on the work piece. The set-up was primitive. However, the results of the following experiments were sufficiently encouraging to continue development of the process and equipment. This was the birth of what later developed into a widely applied new metal forming and assembly technology.The first introduction of EMF equipment in industry was in about 1964 at General Motors for the banding of neoprene boots onto automotive ball joints.
The application and the machine are shown below in Figure 3 and Figure 4 respectively. The machine was technically primitive compared to today’s equipment. However, it served well and for many years produced reliable components for the automotive industry. It was especially useful for manufacturing engineers to learn what can be done with EMF and for the equipment designer to learn what needed to be done to improve the process and equipment.
Within ten years EMF equipment went through several design stages and was sufficiently improved to work reliably as part of a 28 station automated assembly lineFIG:2.1 Neoprene Boots Onto Automotive Ball Joints 2.2Working Principle:In the machine there’s an electromagnet which incorporates a plunger passing through it. The plunger is allowed for vertical motion through electromagnet. The plunger carries an iron core to its upper end, and to the lower end of the same a tool holder is attached, this tool holder holds an embossing tool that is used for cutting the pipe. The plunger is hanged with the help of springs. A working material is placed just below the embossing tool.
Entire assembly is into fabricated housing or body. Whenever electromagnet is made on it pulls the iron core toward it the plunger is forced into downward direction, which pushes the embossing tool against the work (raw) material, thus embossing is carried out, after making the electromagnet dead the spring pulls back the plunger into its original position making it ready for another work material is retracted. 2.3 Objectives :To reduce man power To maintain the accuracy To develop automation unit for the embossing and punching so that m/c can easily be adopted in today’s automated plants. This type of m/c provides work practically at low cost, low maintenance, low capital investment in less space.
To performed the most rigid operation with the high speed. 2.4 Application:Punching Operations in Sheet metals.
Forging or hammering of casting.For Embossing or Making an Impression.Coining Operation can be done by Electromagnet.Numbers on ATM cards.Expiry and manufacturing dates on food containers by embossing machine.
For Different Forming Operations like Punching, Blanking, Embossing etc.This machine can be used for following application of gasket/cardboard/plastic sheets/paper as followsBlanking Punching Embossing Wedding Cards.It Can be Punch up to 15 Gauge (1.45 mm) Aluminium Sheet.2.5 Advantages Construction and Working is Simple.Its capital investment is low.Its Operational cost is low.
It requires very low space.It does not require skilled labour.It does not require periodic check-up and maintenance.Accuracy Can be Maintained.Friction loss is very minimal, due to very little metal –metal contact.Variety of operations can be performed by just using different dies and tool for different operations like punching blanking etc.The force created per stroke can be controlled precisely as it is an electrical system. 2.
6 DisadvantagesElectricity is the core requirement for this machine.High power magnets are required for carrying out operation.The force that is generated is limited and hence it can only be used on thin metals and ductile materials.Can only be used for mass production2.7Disadvantage Of Pneumatic,Hydraulic,Mechanical Machine Over Electromagnetic MachinePneumatic Embossing Machines:More floor area is required due to compressor, air filter; lube tube, dryer, regulators etc.
Seal leakages can cause energy loss.Operation becomes noisy.Hydraulic Embossing Machines:Hydraulic fluid is often corrosive.Loss of energy due to friction.Aeration will cause foaming, degradation of hydraulic fluid, damage to the internal parts.Mechanical Embossing Machines:Power losses due to friction.
Operation becomes noisy operation.CHAPTER-3 Electromagnetic Sheet Metal Cutting Machine(Specification)3.1 Component And Their SpecificationsElectroMagnet:Electromagnetic Winding which contains copper coil because of Copper is good conductor of electricity so copper wire is used for electromagnet. The working principle of electromagnet is based on the faradays left hand rule. The magnetic field produced by the winding, magnetizes the electromagnet.FIG:3.1.1 ElectromagnetThe electromagnet now acts as a powerful magnet and it attracts the mild steel plate which is the good magnetic material.
Here the 2 electromagnet in series is used because the power of both the electromagnet together and we got better result. This force produced is transmitted to the tool for the required forming operations.Frame Material:The first step involved in the fabrication process is materials. Generally Mild Steel is all the required raw materials, the various parts are machined.Fabrication of Frame:The various rectangular components like vertical plate and side plates are machinedSurface grinding is done to finishing of the components. Holes are drilled into the surface by the vertical rectangular structure.
Vertical Push Rod:The material used for the vertical beam is mild steel. When the electromagnet gets magnetized the M.S plate beam Connected to the M.S plate is also goes in downward direction of force.Embossing Tool:The embossing tool is made of High Carbon steel. It is fitted at bottom of the vertical beam. When the force exerted the tool fitted at bottom of rod make and embossing tool up, so that the work piece can be the Embossing mechanism to push the embossing tool up.
Then work piece has got successfully.Spring :157861016700500FIG:3.1.2. SpringThe main purpose electrical supply to the electromagnet is get stopped or cut off. The compressed spring now exerts Force on the vertical bar and lifts it up, enabling the Operator to remove the work piece and load another work Piece.
Before embossing, the spring keeps the vertical bar loaded without obstacle of our spring is twofold. After used for a return mechanically embossed successfully.3.
2 CAD model: CHAPTER-4LITERATURE REVIEW Paper 1 Title: ELECTRO MAGNETIC PUNCHING MACHINEAuthor: Ankit Pawar, Arjun Pawar, Lalit Sillak, Amay TipayleSummary:Punching machine is one of the very important element in paper cutting industries and sheet metal industries. Here researchers had tried to make this machine automatic with the help of electromagnetic principle. The punching is depends on the feed rate which is done manually. Conventional machines are operated with the help of hydraulic or pneumatic principle, which involves large metal to metal contact in driver system as well as, it is also less accurate.
So, researchers have decided to make electromagnetic punching machine. Paper 2Title: MULTI OPERATIONAL ELECTROMAGNETIC FORMING MACHINE Author: Ganshyam Pendurkar, Aniket Naaalkar, Ganesh PendurkarSummary:The purposes of this project are to design and fabricate the economical machine for small sized sheet metal items. Conventionally for manufacturing of these parts large machines are required which is not economical. Also there is wastage of energy due to friction. These problems can be solved by using Electromagnet. Since the actuation occurs electrically operations are frictionless and accurate.Paper 3Title: EXPERIMENTAL STUDY OF SHEET METAL FORMING PROCESSAuthor: Arumugam P, Shanmuga Sundaaram K, Kamala Kannan NSummary:Electromagnetic forming is a high strain forming method which is used for shaping of sheet metals.
An apparatus to test the high speed forming of clamped circular work-piece in electromagnetic forming system is made. In this annealed aluminium sheet is studied. The experiment is conducted for the number of aluminium sheet of different thickness and by varying the energy. Two different spiral coils are wounded. In this the hardness of the work-piece is measured and deformation and microstructure study is done using Electron microscope.Paper 4Title: AUTOMATIC ELECTROMAGNETIC PUNCHING MACHINEAuthor: Saurabh Ravindra kothawade, Shubham Jagtap, Anil WaghmareSummary:The punching machine made by researchers is mainly used to cut strips. Furthermore, they made it as multipurpose machine to cut card board, asbestos sheet, papers, and thin plastic sheets.
This machine is working on the principle of electromagnetic. In this the rate of punching is depends on the federate which is given manually. Paper 5Title: A review on Electromagnetic forming process.Author: Dhiraj Gayakwada, Maheshkumar Dargara, Promodkumar Sharma Summary:Electromagnetic is a high velocity forming method using pulsed magnetic field by application of Lorentz’s forces to work-piece which is made up of electrically conductive material without having working medium and mechanical contact. So, 2D or 3D sheet metal can be cut. In this paper, the research is done on the number of parameters such as work-piece deformation, behaviour of material, energy required during process, acting load and few more.
Paper 6Title: FABRICATION WITH DESIGN OF ELECTROMAGNETIC PUNCHING MACHINEAuthor: Mr. Yogesh D. Pethkar, Prof. A.A.
PatilSummary:Nowadays, in several production factories punching operation is carried out manually or by a machine. These machines are mechanical, pneumatic or hydraulic. These mechanisms are costlier for manufacturing as well as for maintenance and running cost. An electromagnetic machine is better compare to machines with mechanical pneumatic or hydraulic mechanism in above aspects. In this machine the punching operation is carried out on very thin aluminium sheet or other soft sheets. Paper 7Title: EXPERIMENTAL STUDY ON SPRING BACK PHENOMENON IN SHEET METAL Author:S.
A.Satpute, Dr. R.
P.ChopadeSummary:Metal forming processes mostly consist of compression and tension process which involve wide range of operations. As a result this process depends on the various types of parameters. But till date sometimes the selection is done by the trial and error method. Hence proper prediction of the spring for the spring back phenomenon is very important. It depend upon 3 factors i.
e. angle, sheet thickness, width of the w/p.Paper 8Title: MULTI-PURPOSE FORMING MACHINEAuthor: Nihar N. Rege1, Akash B. Kotian, Harshal S.
Naik,Urvesh D. BhirudSummary:The main aim of an engineer is to utilize the resource to the fullest and to come up with a creative idea to solve the various problems of the society. In today world it has been proved that the production rate of machine is much more than that of the manual production rate. As a result every industries uses machine for the various process. But the machine can perform only one operation at a time.
This is a very time consuming process. As result the need of machine occur, which can perform various sheet metal operations.Paper 9Title: METAL FORMING BY COLD EXTRUSION PROCESSAuthor: R.Sathish, S.Vasanthakumar, S.Sasikumar, M.YuvapparasathSummary:Metal forming by an extrusion process plays a crucial role in metal forming process which is widely accepted in industries.
Due to this process we can reduce the defects in the manufacturing of the w/p. Here there are two processes i.e.(1) cold extrusion and (2) hot extrusion of which each has its own merits and demerits.
In our project, we use a punching press that is pressed downward and as a result due to the impact of force various operations are performed by the machine.Paper-10:Title: Review On Electromagnetic Multipurpose MachineAuthor: DaraniyaDivy, VaghelaHarshit, RajgorRatna, TurakhiaSamvegSummary:In the present world there is a need of forming machine which can efficiently perform the various sheet-metal forming processes such as blanking, piercing, lancing, notching etc. These operations can be performed hydraulically, pneumatically, and by the mechanical press.
The main problem with this machine is the cost of this machine. In addition to the 3 method another method known as electromagnetic is also there. With this process the metal forming operation can be easily performed with less cost as compare to another. In this process current pass through electromagnet as a result the plunger attached to it is forced down and cutting operation take place.
CHAPTER-5PATENT SEARCH ACTIVITYTitle:Electromagnetic Hemming Machine ; Method For Joining Sheet Metal Layers Inventors : John L McClure Patent Number : US6927370B2 Publication Date : 05/26/2005 Summary : Electromagnetic forming is a type of high velocity, cold forming process for electrically conductive metals.It is most commonly use for copper and aluminium. The workpiece is reshaped by high intensity pulsed magnetic fields that imparts a current in the workpiece and accordingly a repulsive magnetic field, rapidly repelling portions of the workpiece is generated. The workpiece can be reshaped without any contact from a tool, although in sometimes the piece may be pressed against a die or former.
This technique is sometimes called as high velocity forming or electromagnetic pulse technology.Title: Metal Stamping Inventors : Glenn W Greenway Patent Number : US5265320A Publication Date : 07/22/1991 Summary :According to this invention,a die is provided during the stamping operation so that at the time of cutting stress are not produced.This is done by punching an hole in the sheet metal strip, cutting the strip with a cut-off punch and peening the sheet metal to form a pair of dents on opposite sides of the aperture on a line parallel with the cut-off punch.Due to this the stress which were previously produced during the stamping operations is removed.As a result during this process the metal gets easily cut with the deformation or harm to the workpieceTitle: Metal Cutting Process Inventors : Bertuzzi, Renato Patent Number : 09/752141 Publication Date : 12/29/2000 Summary : The method is relates to cutting a sheet metal, in which there is a cutting head that is able to cut profiles in two dimensions, i.
e. x-y plane.For an example such as metal sheet or plate.Also includes movable beds, on which the w/p material is loaded. The beds are movable such that once a bed is loaded, it can be relatively quickly moved into a cutting position under the cutting tool, by which it can be cut.
Once the cutting operation is complete, the first movable bed can be moved away quickly, and another bed can take its place in the cutting position.As a result the productivity of the cutting process is increased by keeping the machine busy while the first, and other, carriages are being unloaded and loaded.Title: Machines For Cutting Sheet Material, Sheet Metal Inventors : Alves Cantelli Patent Number : 04/844294 Publication Date : 07/24/1969 Summary :The object of the review is to provide improvements for machines of this kind, and particularly to the guide edges.the improvements consist of automatic means for positioning the guide edges in such a way that enable the production of sequences to perform atleast two operation at different positions. Another object of the present invention is to provide the cutting tool to be subject to the proper positioning of the item being cut in relation to the guide edges; this positioning is achieved by pneumatically or hydraulically operated means.5) Title: Piler Mechanism For Sheet Metal Inventors : Buccicone Dario Patent Number : US3256011A Publication Date : 06/14/1966 Summary : A piler machine for sheets metal which consist of a rail type overhead electromagnetic conveyor which is mounted at opposite ends on frames and have travelling belts for advancing on the bottom face. Therefore sheets that enters to an entrance end of the conveyor and advanced to a piling area between said end frames.Also there is an end stop device whose function is to properly handle the sheet that are coming from the entrance of the conveyor and place those sheet parallel to each other so that the sheets get to the machine automatically.
As a result the sheet gets to the machine automatically and the production increasesCHAPTER-6 CANVAS6.1 AEIOU Canvas:FIG:6.1 AEIOU Canvas 6.1.1 Environment:SummerRainyNoisyCrowdGIDC area 6.1.2 Interaction:Design EngineerMarketing PersonProduction EngineerQuality Control PersonWorkers 6.
1.3 Objects:Drilling MachineBending MachineMeasuring TapeVernierHammerScrew Driver 6.1.
4 Activities:Design DepartmentQuality DepartmentStoresMachining ShopAssembling Shop Users:Production EngineerDesign EngineerWorkerQuality EngineerMarketing Person6.2 Empathy Mapping Canvas:FIG:6.2 Empathy Mapping Canvas 6.2.1 User:Industrial People Engineers Worker Workshop 6.2.
2 Stake Holder:Team member Engineer Company management Share holder 6.2.3 Activities:Cad design File making Research paper study Patent study Market survey 6.
2.4 Happy Story:Production very rate high time is very saving and company staff happy Time saving low afford worker are happy 6.2.
5 Sad Story:Machine costing high not afford company Machine size large workshop size very low Machine use electric power Ideation Canvas: FIG:6.3 Ideation CanvasActivity:Cad design File making Research paper studyPatent study Market survey People :Worker Employ Engineering Store manger store keeper workshop manger Situation, Context, Location:work shop industries collage machines Possible Solution: low power consumption very less pollution low maintenance high speed output very less noiseproduct development canvas:FIG:6.4 Product Development CanvasPurpose: To provide finished product as per the requirement of the customer To provide good quality product to industries product can obtain in short time and easily Easy to use Product Experience: Satisfy with quality of product Satisfy with cost and quantity of the product Product should be ease in application Product functions:Newer technology equipmentEasily prepare Less time consumingGood qualityAvailable as per different requirementProduct features:High efficiencySafetyMaintains operating conditionIncrease in working capacityCustomer Revalidation:Good quality Customer Comfortability Ease in application 6.4.6 People:Customer Engineer Worker Industrial 6.4.7 Components:Sheet metalCopper coilWireMild steel angle Reject, Redesign, Retain:Wiring rejection (redesign) Structure(frame ) (redesign) Unavailability of product in large amount High product cost CHAPTER-7DESIGN CALCULATION ; COST7.
1 Design CalculationCalculation of Electromagnetic Force :Electromagnet:-Current = 28 ampVoltage = 12 vNo. of turns (N) = 625Diameter of rod (D) = 0.02 mµo = 4? 10-7 H m-1 F = Force in NewtonB = Magnetic Flux in teslaA = Area of Magnet µo = Permeability of Free Space 100965015240006166881559500FIG:4.1 Graph Of Force VS No. Of TurnsElectrical power = V × I =12×28 =336W Magnetic field intensity (H) = N × I / length = 625 × 28 / 0.07 =250000 AT/m -Magnetic Flux Density ( B )= H × µo =250000 × 4?× 10-7( µo = 4? × 10-7 ) =0.3142 tesla or wb/m2 Force ( F)= B 2 × A / 2 × µ o (A = ?/4 ( D1 2 – D2 2 ) ) = 0.
31422 × 3.45 ×10-3 / 2 × 4? ×10-7 = 135 N or 13.8 Kg 7.
2 Cost Estimation:SR NO COMPONENTS NO OF COMPONENTS PRICE PER PIECE1 Electromagnet 1 7000/-2 Spring 1 800/-3 Pushrod 1 500/-4 Embossing tool ready 1 720/-5 Embossing die ready 1 450/-6 Iron core 1 2000/-7 Welding labour1 780/-8 Wastage allowances 720/-9 Pipe D100mm* L1000mm *5mm 1 1250/-10 Ms plate 1000*1000*5mm 1 1200/-11 Other cost wire 500mm L 2mm T 250/-12 Nut bolts 6mm 12 80/-Total cost 15750CHAPTER-8CONCLUSION;FUTURE SCOPE8.1 Conclusion:This machine can be fixed in less place ,requires low maintenance ,does not require skilled labour has high rate of action , has longer span of time , require less capital investment , has low running cost hence can be implemented in the industry to help to lower down the production cost.Automating this unit gives a unique advantage of interfacing this unit in industrial automation unit,For more fast production rate and virtually endless working hours.This very basic and unique ability of this machine can put itself at remarkable less cost in the industry.After clearing disadvantage associated with and after few further modification suggested in the relevant chapter, the project work thus execute can find its way directing in the industry for implementation.8.2 Future Scope:The flux of electromagnet can be increased by increasing size of the same and by increasing the coil turns. So this modification enables this machine to emboss or punch harder materials such as steel.
Automation can be implementing by adding roller and feeder mechanism.This can be used for the All Forming Operations by Changing the Design of the Tool and Die and by changing the structure depending upon the application.Overall capacity can be increased by Increasing No. of Turns in the magnet or by setting the no. of small capacity Magnets in series.
It Can be used for the different types of Punching and Blanking operations.This machine can be controlled by computer also. CHAPTER-9CHALLENGESFirst challenge in this project is to supply higher amount of current so that a thick sheet metal can also be cut.Second challenge in this project is to increase the force capacity. Third challenge in this project is to use the same machine for different types of forming operation.Fourth challenge in this project is that, that how we can make this machine automatic.
Fifth challenge in this project is to select high power magnet in such a way that the overall cost of the project does not get affected much.The sixth challenge in this project is to make this machine use for batch as well as job type production process. CHAPTER-10 PAPER PUBLICATION Title: ELECTRO MAGNETIC PUNCHING MACHINEAuthor: Ankit Pawar, Arjun Pawar, Lalit Sillak, Amay TipayleTitle: MULTI OPERATIONAL ELECTROMAGNETIC FORMING MACHINE Author: Ganshyam Pendurkar, Aniket Naaalkar, Ganesh PendurkarTitle: EXPERIMENTAL STUDY OF SHEET METAL FORMING PROCESSAuthor: Arumugam P, Shanmuga Sundaaram K, Kamala Kannan NTitle: AUTOMATIC ELECTROMAGNETIC PUNCHING MACHINEAuthor: Saurabh Ravindra kothawade, Shubham Jagtap, Anil WaghmareTitle: A review on Electromagnetic forming process.Author: Dhiraj Gayakwada, Maheshkumar Dargara, Promodkumar Sharma Title: FABRICATION WITH DESIGN OF ELECTROMAGNETIC PUNCHING MACHINEAuthor: Mr. Yogesh D. Pethkar, Prof. A.
A.PatilTitle: EXPERIMENTAL STUDY ON SPRING BACK PHENOMENON IN SHEET METAL Author:S.A.Satpute, Dr. R.P.ChopadeTitle: MULTI-PURPOSE FORMING MACHINEAuthor: Nihar N. Rege1, Akash B.
Kotian, Harshal S. Naik,Urvesh D. BhirudTitle: METAL FORMING BY COLD EXTRUSION PROCESSAuthor: R.
Sathish, S.Vasanthakumar, S.Sasikumar, M.
YuvapparasathTitle: Review OnElectromagnetic Multipurpose MachineAuthor: DaraniyaDivy, VaghelaHarshit, RajgorRatna, TurakhiaSamveg CHAPTER-11REFERENCES1 ?Process Design and Development of Electromagnetic Shearing Machine? by Sagar P.Kulkarni, Shailesh B. Wahulkar, Swapnil M. Yeole, Anant Kumar, Mangesh P. Naik, Sushil D. Yeole,2 Paper on ?Novel Design and Model of Punching Machine Driven By Electromagnetic Actuator? by R. Srinivasa Sugash, Mohamad Raseem .
F, Shyam Sundar S, Tarun Veeraraghavan SSN College Of Engineering/Department Of Mechanical Engineering,Chennai, India,Khurmi and Gupta, 2005, ?Machine Design?, S. Chand and Company Ltd, pp, 820-825. Prof. V. B.
Bhandari, 2007, ?Design of machine Elements” Tata McGraw Hill Publishing Co. New Delhi, pp 49-52.5 Sen and Bhattacharyya, 2006, ?Principles of machine tools?, New central book agency,Kolkata, pp 319-384.Websites :https://en.wikipedia.org/wiki/Electromagnetic_forminghttps://www.sciencedirect.com/science/article/pii/S2211812814004313https://www.researchgate.net/publication/270222802_Experimental_Study_of_Electromagnetic_Sheet_Metal_Forming_Processhttp://www.engineershandbook.com/MfgMethods/emforming.htmhttp://www.freepatentsonline.com/result.html?sort=relevance&srch=top&query_txt=electromagnetic+sheet+metal+cutting+machine&submit=&patents_us=onhttps://nptel.ac.in/courses/112107144/Metal%20Forming%20&%20Powder%20metallurgy/lecture9/lecture9.htmCHAPTER-12APPENDIX
