Explosive forming between 1968 and 1972, arpa supported an effort proposed by the university of denver to use explosives for forming metal parts for aerospace applications. Dynamic plastic deformation, explosive forming, gurneytheory. Introduction the explosive forming of metals has been known for about. Practical research on explosive forming of pipeshaped specimens has been conducted since 1970, in the g. Explosive forming operations can be divided into two groups, depending on the position of the explosive charge relative to the workpiece. Closecontact operations are used to a lesser extent and for more sophisticated processes such as extruding, cladding welding, powder compaction and. In this process the punch is replaced by an explosive charge. Explosive forming of plates find suppliers, processes. Feb 27, 2017 electro hydraulic metal forming unconvential metal forming. Apr 09, 2018 forming, also known as metal forming, includes a wide range of manufacturing processes in which metal is deformed into a required shape by the application of suitable stresses. Sheetmetal characteristics elongation the capability of the sheet metal to stretch without necking and failure. Progressive forming rubber hydroforming bending and contouring spinning processes explosive forming shearing and blanking stretch forming deep drawing. Multishot explosive forming is sometimes carried out automatically the charges are fed in from a special supply bunker.
Sep 29, 2015 comparison of metal forming processescomparison of metal forming processes 34. Any product size, shape and sheet thickness is possible. Unfortunately, poor drawability of some materials makes it impossible to use classical forming methods. Friction is responsible for, or adds to, the wear of tools and affects the surface finish of the product. Sometimes called explosive hydroforming, a workpiece and explosive is placed in a tank of water. Unlike this older method, which shapes metal using pressurized hydraulic fluid pumped into a forming chamber, herf techniques utilize an explosive charge to create the necessary pressure. What is explosive forming process the metal forming involves the detonation of an explosive.
Where possible, the limits governing each process are identi. Explosive forming was first proposed at the kharkov aviation institute in the 1940s and was widely used in the mid1950s in the production of oversize parts for rockets and airplanes. Explosive forming process high energy rate forming process engineering study materials. Process design is the ensemble of operations leading from the design geometry to the dieface. Ge engineers used this innovative composite material to produce multilayer vacuum tube anodes aka plates with superior heat transfer characteristics. Explosives commonly used are explosive chemicals, gaseous mixtures or other fuels. Explosive forming free download as powerpoint presentation. The effect of the extrusion ratio r on the shape of the tool is indicated in figure 4.
Special forming process sheet metal explosive material. Explosive forming an overview sciencedirect topics. The process involves stretching the sheet to a calculated yield point and forming it over a tool. Explosive forming process explosive material explosion. The process derives its name from the fact that the energy liberated due to the detonation. This process can deliver a great deal of flexibility in the metalforming process. Formability has been defined as the ability of a sheet metal to be deformed by a specific sheet metal forming process from its original shape to a defined shape without failure.
These disadvantages can be eliminated by using the unconventional technologies of explosive forming. These cracks meet each other and separation occurs process parameters. With flatplate designs, explosive hydro forming is very comparable to stamp or press forming. Comparison explosive forming in explosive forming an explosive charge is used instead of a punch or press. Metal forming is the main method of making metal products and semifinished products. Therefore, hollow profiles can be compressed or expanded as well as 2d or 3d sheet metal can be shaped, joined or cut. Explosive forming process high energy rate forming.
Jun 04, 2018 explosive forming process high energy rate forming process engineering study materials. Detonating a charge above the plate rapidly forces the metal into the desired shape. Sheet stretch forming sheet stretch forming is a fast, economical, and accurate way to form a large panel from a metal sheet. Explosive forming of a part may be carried out by using large charges in a single explosion socalled singleshot explosive forming or by using a series of small charges multishot explosive forming. To make the metal plastically deformed, forces must be applied that are greater than the yield strength of. This technology is labor intensive, but requires only singlesided tooling.
Electro hydraulic metal formingunconvential metal forming. Explosive forming is an ideal process for producing low volumes of very large metal part with low tooling costs. In these cases, forming in higher temperatures 79, superplastic forming spf 10 11, high. Metal forming processes full notes ebook free download pdf. Explosive forming definition of explosive forming by the. This process can deliver a great deal of flexibility in the metal forming process. The main elements involved in the explosive forming process are. Applications and capabilities of explosive forming. Presentation on the topic mechanics for explosive forming process. Explosive forming is labor intensive, but requires only single. Progressive forming shearing and blanking hydroforming bending and contouring stretch forming spinning process explosive forming deep drawing stamping suranaree university of technology september 2007. High velocity forming hvf refers to a unique set of methods which are used for metal forming and utilizes a concept which is basically different from that used in conventional forming techniques.
Tno is involved in development of the explosive forming technology for the fabrication of metal sheets and plates. Explosive forming for a good recent overview, the reader is referred to 1 is therefore explored to assess the potential of this essentially cold forming process, based on the idea that all. German democratic republic, at the ludwigsfelde truck company and at the magdeburg technical university. Adamsons work in 1876 and 1877 was perhaps the first related investigation to be described in the scientific literature. This characteristic allowed ge to build significantly higher power. No preheating required before the explosive forming less production cost. Bending, stretching and drawing of simple shapes are analysed, as are certain processes for forming thinwalled tubing.
Both the form and the plate is submerged in water so that it is covered by a wide margin. These techniques could include methods such as explosive forming. Aerospace metal forming technologies aries alliance shaping a better future 3. As the name itself hints, hvf or high velocity forming refers to a set of techniques which are used for metal forming. Explosive forming can be used to easily produce difficulttomanufacture components. Although explosive forming cannot be regarded as a substitute for existing processes, it is an extension of the techniques now in use in the sense that it enables a number of difficult materials to be formed to a high degree of accuracy and at low cost. There are a great variety of sheet metal forming methods, mainly using shear and tensile forces in the operation. Explosive forming a method of forming metals, mainly sheet metals, in which pressure is created by the force of the blast of a high explosive, powder, or gaseous mixture through a transmitting medium. In the long and often melancholy history of explosives the constructive use of explosive forces to shape metals is comparatively new. The forming processes are affected by the rates of strain used. Explosive forming is a process in which forces produced by an explosion are used to shape a workpiece. The beginning of the use of explosives for forming of metals dates to 1888 when the earliest recorded application is described as the engraving of iron plates by imprinting a design on a block of explosives or by interposing a stencil between the explosive and the plate. Explosive forming definition of explosive forming at.
Forming, also known as metal forming, includes a wide range of manufacturing processes in which metal is deformed into a required shape by the application of suitable stresses. An explosive charge 2 is immersed in the water and placed just above the center of the plate. Stresses beyond yield strength of the workpiece material is required. Manufacturing companies producing metals supply metals in form of ingots which are obtained by casting liquid metal into a square cross section. Practically all metals, which are not used in cast form are reduced to some standard shapes for subsequent processing. The underwater process relied on a mold for the part over which was placed a plate of the metal alloy to be used. Explosive forming article about explosive forming by the. More than 90% of smelted metal is processed by different methods of metal forming. Please help improve this article by adding citations to reliable sources. Therefore, the forming limits can be extended for several materials. Explosive forming process high energy rate forming process. Metal forming processes indian institute of technology.
It can be used on materials for which a press setup would be prohibitively large or require an unreasonably high pressure, and is generally much cheaper. Mechanics of sheet metal forming college of engineering. Explosive hydroforming is a metal forming technique that uses the energy generated by an explosive detonation to form the metal work piece. The explosive energy replaces the male part of the tool that is used in regular forming processes.
Metal drawing powder processes high energy rate forming high energy rate forming is the forming of sheet metal by a high energy surge, delivered over a very short time. Applications and capabilities of explosive forming request pdf. In the late 1950s, the general electric company developed an application for fivelayer sheet metal composites that had been created using the explosive forming process. To make the metal plastically deformed, forces must be applied that are greater than the yield strength of the metals. It can be used on materials for which a press setup would be prohibitively large or require an unreasonably high pressure, and is generally much cheaper than building a large enough and sufficiently highpressure press. Explosive forming is a metalworking technique in which an explosive. Explosives are also used to compact or consolidate metal powders into near net shapes. Oct 25, 2016 comparison explosive forming in explosive forming an explosive charge is used instead of a punch or press. Explosive forming is best described as a these shortrun applications are the short lead process in which metal parts are formed by the times required and minimum expenditures for high pressures resulting from the detonation of tooling.
Explosive forming, however, is not necessarily a replacement for conventional metal forming techniques. This presentation will focus on the different uses and methods of explosive forming in the aerospace as well as automotive industry. Standoff method in this method, the explosive charge is located at some predetermined distance from the workpiece and the energy is transmitted through an intervening medium like air, oil, or water. In normal explosive forming operations, the major characteristics of the work metal that determine formability are ductility and toughness. Results are presented of the development of explosive forming technology for metal sheets and plates. Explosive forming explosives are used primarily for shaping sheet, plate and tubes, and for sizing and flanging, all these operations being of the standoff type. Plastic properties of metals are used during the process of metal forming. Explosive forming is a metalworking technique in which an explosive charge is used instead of a punch or press. The temperature of work is increases due to adiabatic heating. Electromagnetic forming process has very high strain rate and velocity in comparison to conventional process. Self reading for your interestself reading for your interest defects in metal forming processesdefects in metal forming processes and their remedies. Detonation of the explosive forces the workpiece to assume the shape of the tool. Explosive hydroforming, also known as herf high energy rate forming or exploform, is a striking alternative to the more traditional process of metal hydroforming.
Advantages o it can simulate a variety of other conventional metal forming techniques such as stamp or pressforming and spinforming in a single operation. The explosive metal forming process this technique uses the energy generated by an explosive detonation to form the metal work piece. Unsourced material may be challenged and removed january 2012 learn how and when to remove this template message. On detonation of the explosive charge, a pressure pulse or a shock wave of very high intensity is produced. Explosive forming is the forming of sheet metal using explosive materials using large amounts of energy over a very short time. Process design is the ensemble of operations leading from the design geometry to. High energy rate forming is the forming of sheet metal by a high energy surge, delivered over a very short time. Explosive forming or herf high energy rate forming can be utilised to form a wide variety of metals, from aluminium to high strength alloys. The ability to quickly prototype a unitized figure 4.
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