Showing papers on "Sheet metal published in 1988"

Integrated down converter and interdigital filter apparatus and method for construction thereof

Abstract: An integrated down converter and interdigital filter apparatus having a down converter and a number of interdigital filters mounted on the same printed circuit board and installed in the watertight housing. The housing of each interdigital filter is cut from sheet metal, with a conductive surface on the printed circuit board as one side. A method for construction of the interdigital filter is also set forth.

Plastic and viscoplastic flow of void‐containing metals. Applications to axisymmetric sheet forming problems

Abstract: A formal analogy between the equations of pure plastic and viscoplastic flow theory for void-containing metals and those of standard non-linear elasticity is presented. The formulation is particularized for the analysis of axisymmetric sheet metal forming problems using simple two node linear finite elements. Details of the treatment of friction and strain hardening phenomena, time increment computation and elastic effects are also given. Examples of the effect of void porosity on the hemispherical stretching of a circular sheet are presented.

Analysis of superplastic metal forming by a finite element method

Abstract: A finite element velocity method for analysing the superplastic sheet metal forming process is presented. This method is developed from the principle of virtual work and is based on the use of isoparametric continuum elements. The large inelastic deformation of the superplastic material is modelled as the behaviour of an incompressible non-linear viscous flow material. The contact and friction problem is solved by using the compatibility load step method, which is an extension of an earlier work. The finite element method is applied to selected problems to illustrate the applicability of the solution procedure.

Honeycomb structure, in particular with s-shaped, partially reinforced layers of sheet metal

Abstract: A honeycomb structure, in particular a catalyst support, preferably of circular, oval or elliptical cross-section, is made of a pile of sheet metal plates (1, 2) intertwined in opposite directions and arranged in a tubular sheath (7). To stabilize the entire structure and to prevent extraction of the sheet metal plates (1, 2) from the tubular sheath (7), some of the sheet metal plates (8, 9, 10) are thicker than the others, because these layers (8, 9, 10) are made of thicker sheet metal or a plurality of contiguous thinner sheet metal plates. The thicker sheet metal layers stabilize the entire structure and prevent, in particular, deformation of the tubular sheath due to high internal pressure at elevated temperatures, even in structures of oval or elliptical cross-section.

Development of multistage sheet metal forming analysis method

Abstract: The multistep sheet metal forming process for axisymmetric shapes has been modeled employing a simplified finite element analysis method. The analysis is based on the idea of dividing the deformation history into several steps while applying the total strain theory of plasticity in each step. An algorithm has been developed which satisfies the potential energy minimization process at the entire nodal point grouping in each step of the forming process. Although numerical solutions have been obtained up to a four-step process, there are no inherent limitations in the basic methodology to extend it to any number of steps. The assumption of proportional loading in each step of forming was carefully examined by comparing the computed principal strain ratios with those of experimentally observed values. It was found that some regions of the sheet material undergo nonproportional straining; consequently, a single-step approximation for a multistage forming process may not give a valid result. Sensitivity of the new model to the number of intermediate steps has also been examined. It is concluded that the new model is a good approximation of the multistage sheet forming process.

Calculation of Springback and Its Variation in Channel Forming Operations

Abstract: An approximate plane strain analysis of the springback of sheet metal which has been bent under tension around a small radius is presented The tensile load can be applied either before the bending takes place (called a «preload») or after bending («postload») Some of the material and process parameters which govern springback are identified, and it is shown that postloads are always more effective than preloads in reducing spring-back

A finite element simulation of the sheet metal forming process

Abstract: A finite element simulation code of the sheet metal forming process has been developed. This simulation code plays an important role in the computer aided engineering (CAE) system for an automobile parts forming process, which includes the pre- and post-processes. The paper presents the development of an updated Lagrangian type finite element modelling, based on the elastic–plastic (J2 flow law) membrane shell theory. An attempt is made to calculate the strain distribution incurred by peripherally clamped or non-clamped square plates when impressed by rigid punches. These are the cases of square box-shape punch drawing and arbitrary shaped panel stretch forming.

Magnetic, hot-melt adhering soundproofing sheet

Abstract: Bubble-formation when melting a magnetically adhering bituminous soundproofing sheet provided with a hot-melt adhesive layer (4) onto an automobile body sheet metal at temperatures of about 190° C., is prevented by integrating a flexible, temperature-resistant foil (5) into the soundproofing sheet. For soundproofing sheets up to 3 mm thick, the spacing between the hot-melt layer (4) and the foil (5) preferably should not exceed 1 mm.

Method for continuous fabrication of fiber reinforced titanium-based composites

Abstract: A method for continuous fabrication of a filament reinforced titanium base alloy sheet is provided. The sheet is formed by first assembling a number of individual silicon carbide filaments to form a tape. The tape is passed across a drum in a low pressure plasma deposition apparatus where the surface of the drum is formed of a polished and cooled refractory metal. The tape is sprayed with a plasma spray of the titanium base alloy metal to form a sheet of such metal on the tape and on the surface of the drum. The deposited sheet including the silicon carbide reinforcement tape is removed from the drum surface by peeling. The peeled product is a composite of titanium base sheet metal which is impregnated with the filaments of silicon carbide, i.e. a metal impregnated tape.

Apparatus for flow-through treatment of textile material, paper, or the like

Abstract: A permeable drum for the wet or dry treatment of textile material, paper, or other permeable materials of a certain width has a screen-like cover supported solely on narrow sheet metal strips or narrow webs. The sheet metal strips extend axially parallel, their extension in width being oriented in the radial direction. The webs are oriented in the peripheral direction and form part of the connecting elements between the sheet metal strips, these connecting elements also carrying the screen-type cover. The connecting elements, also serving as spacers, are formed of one piece and connect two neighboring sheet metal strips. Connection of the spacers with the sheet metal strips is achieved by screws, bolts or the like, of which suitably two in superposition extend longitudinally through bores in the connecting elements. While the web of the connecting element is fashioned to be narrow, the base should be broader in order to provide a good seal for the peripheral region of the drum that is not under a suction draft.

Electric machine with a sheet metal packet carrying a winding and a method of making same

Abstract: An electric machine that includes a stator having a sheet metal packet which has an end plate at each end, and insulating plates abutting against the end plates. The packet has radially inwardly opening winding grooves. Insulating plates are provided at the ends of the packet and have recesses that correspond to the grooves and ribs that form abutment faces against which winding liners provided in the grooves abut. The ribs are shaped such that the windings emerging from the grooves will not cut through the liners when bent sharply. The ends of the groove liners are shaped by thermal stamping to lie against the side faces of the ribs.

Method of forming a hollow fastener from sheet metal

Abstract: A method of forming an integral fastener such as a rivet on a sheet metal component such as part of a clutch plate assembly. The method involves placing the metal sheet between a pair of dies so that portion of the sheet overlies a cavity in one die. The other die has an annular working face which surrounds the cavity in immediately adjacent relationship. A biased plunger is arranged for movement relative to both dies and is receivable in the die cavity with clearance. That plunger is engaged with the sheet portion on the side thereof opposite the cavity so as to apply a bias force to that portion which acts in the direction of the cavity. The annular working face is then applied to the metal sheet so as to compress an annular zone of that sheet. The combined effect of the bias force and the compression then causes material to yield in the annular zone and to be displaced from that zone to flow into the die cavity to form a hollow fastener in the clearance between the cavity and the plunger.

Method for producing protected metal bases for aerosol valves and the like

Abstract: According to the method, after the metal base for the aerosol valve or the like has been formed by conventional methods from sheet metal, a layer of protective plastics material such as polyethylene or polypropylene is applied to at least one of its sides. This application can be done by known methods such as spraying or immersion. The metal base can be formed from unprotected steel which is tin-, nickel- or chromium-plated, or from varnished aluminium alloy. The plastics material is preferably applied differentially to obtain selectively different layers on the metal base, for example a greater thickness on the inside of its rim, this being the region where the base is clinched or otherwise fixed to the container.

Impeller made from a sheet-metal disk and method of manufacturing same

Abstract: An impeller formed from sheet-metal by stamping and bending, at a low production cost, capable of delivering an increased quantity of air at a reduced noise level and with reduced power consumption and enhanced efficiency. The method of manufacturing the impeller from sheet metal incorporates sufficient versitility to allow the blades of the impeller to be formed to any desired configuration in order to provide an optimum shape for the intended impeller use. The blades can be curved or twisted and can extend perpendicular from the sheet-metal surface or at any desired angle for optimum utilization.

Improved electric heater

Abstract: An improved electric heater comprises two layers of thin perforated metal sheet 4 between which a length of resistance wire 2 (optionally coated with an insulating layer) is contained in an arrangement evenly disposed over the length and width of the heater. Above the metal sheets 4 layers of thermally conductive material 5 act to diffuse the heat created by passage of an electric current through the wire 2. Layers 5 may be expanded sheet metal or random strips or wire. Below the metal sheets 4 further layers are provided, the thermal conductivity of which can be adjusted by suitable use of thermally conductive and insulating material. The layers 5 are contained by expanded metal sheet layers 6 and 8 which form upper and lower heat transfer surfaces, the combined layers 4, 5, 6 and 8 being retained in thermal contact with one another by a U-shaped frame 1. The heater combined with a thermostat and a flexible insulating enclosure find application in the protection of water storage installations against frost.

Analysis of tin diffusion in the preparation of Nb3Sn superconducting wire and sheet

Abstract: Both the external and internal methods of producing Nb 3 Sn/Cu superconducting wire have been modeled by experiments in which tin was diffused into copper from externally plated layers on copper sheet and wire and from internal cores in copper wire. The experiments were done at 200 °C where tin melting is avoided, and the times required to eliminate the tin layer were evaluated both experimentally and from numerical solutions of the diffusion equation. The sheet study allowed a re-evaluation of the tin diffusion coefficient and verification of the validity of the numerical technique. Reasonable agreement was obtained between the experimental and theoretically predicted times required to eliminate the tin layers in both external and internal wire geometries.

Sheet metal bending tool

Abstract: A sheet metal bending tool is disclosed uniquely adapted for bending and repairing automotive sheet metal parts. The tool includes at least a shank and a hook end portion designed to facilitate holding and bending of sheet metal edges in a variety of applications. In a preferred embodiment, the tool also includes a "V" shaped inner surface specially adapted to grip metal pieces. Alternate constructions of the tool may include a useful ring-end portion or a second hook end portion to increase the range of applications for the tool.

Method of manufacturing a sheet metal poly-V pulley

Abstract: A method of manufacturing a sheet metal poly-V pulley including forming a tubular peripheral wall integrally from the peripheral edge of bottom wall and forming poly-V grooves in the peripheral wall at specified pitches, in which a bent part is formed in the bottom wall in an annular form concentric with the axial center of the peripheral wall and bulging out in a convex form toward the opening side of the peripheral wall. The load from the poly-V belt which may cause plastic deformation of the sheet metal poly-V pulley is absorbed by this bent part, so that the increase of material cost, difficulty in forming, and increase of weight due to increase of the thickness of the blank of sheet metal poly-V pulley in order to enhance the strength may be avoided.

Al brazing sheet

Abstract: PURPOSE:To obtain an Al brazing sheet particularly improving the corrosion resistance of a heat exchanger, by cladding both sides or one side of an Al-alloy core material which contains respectively prescribed amounts of Cu, Mn, Si, and Fe and in which grain size is limited with an Al-Si or Al-Si-Mg alloy brazing sheet metal. CONSTITUTION:An Al-alloy core material which contains, by weight ratio, 0.3-0.9% Cu, 0.5-1.5% Mn, <=0.2% Si, and 0.2-1.0% Fe and in which grain size is regulated to 50-150mum is prepared. Moreover, the grain-size control of the above core material is carried out by controlling the homogenizing temp. of the core material. Then, both sides or one side of this grain size-controlled core material is clad with an Al-Si or Al-Si-Mg alloy brazing sheet metal. In this way, the Al brazing sheet having the above-mentioned characteristics, improved in strength by about 30% as compared with the conventional sheet, and capable of reducing the sheet thickness to about 0.6-0.45mm can be obtained.

Fifty Years of Sheet Metal Formabslity — Has Science Replaced the Art?

Abstract: This paper begins with a brief description of sheet metal forming, both then and now, and concludes by examining the question of whether science has replaced the art in sheet metal forming

Method of making complicated sheet metal parts, and device for carrying out the method

Abstract: Method of making complicated sheet metal parts in one, two or more operation/operations, at least one operation comprising a plurality of processing steps. The sheet-metal blank is placed on the tool and the pressure is then increased continuously up to, for example, 800 bar, passing through different pressure phases, in the first phase a continued flow of the material into the recesses of the form tool taking place and, in the subsequent phase, the forming blank being trimmed in an intermediate stage at relatively low points of the tool, the material flowing further into the recess, corners and undercuts. The pressure is then increased until the end phase and the workpiece then undergoes final stamping, final trimming, perforation and/or edging. The pressure is then reduced and the sheet-metal part removed. (Figure 3).

Overhead magnetic blank unloading conveyor

Abstract: A conveyor belt apparatus is mounted between the upper and lower die shoes of a press for removing a metal blank from the press. The conveyor has magnetic means for magnetically attracting the workpiece to the underside of the belt as it is being moved from the press at right angles from the direction the sheet metal is fed into the press.

Flat-rolled steel can stock product

Abstract: Composite-coated flat-rolled steel can stock processing and product for fabrication of sheet metal cans, in particular for three-piece, welded or cemented side seam cans. Single or double-reduced, low carbon, flat-rolled steel of a gage in the range of about 55 to 110 pounds per base box is flash coated with tin (0.05 #/bb), which is alloyed with the steel base metal; at least 0.20 #/bb of tin is added to one surface only, flow brightened and water quenched; chemical treatment chrome oxide coating of about 100 to 750 milligrams per square foot is added to both surfaces and an organic coating of 2.5 to 15 milligrams per square inch is added to the surface which is free of flow-brightened tin for disposition internally of a can fabricated from such coated can stock. The equivalent of quarter-pound and higher coating weight tinplate protection is provided while decreasing tin requirements and maintaining three-piece can fabrication properties not available with coating metal substitutes for tin.

Influence of Anisotropy in Sheet Metal Forming

Abstract: Numerical analysis is carried out in order to investigate the influence of plastic anisotropy on sheet metal forming processes such as stretching and deep-drawing. The analysis is based on the deformation theory and Hill’s theory of plastic anisotropy. The numerical results are compared to experiments. It is shown that the neglect of the anisotropy in the simulations leads to inaccurate results. Using the yield stresses and anisotropic parameters from tensile and bulge tests, the earing in deep-drawing of a circular blank is calculated correctly.