Types of press tools
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Types of press tools Press tools are commonly used in hydraulic, pneumatic, and mechanical presses to produce components at high volumes. Generally press tools are categorized by the types of operation performed using the tool, such as blanking, piercing, bending, forming, forging, trimming etc. The press tool will also be specified as a blanking tool, piercing tool, bending tool etc.
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Classification of press tools Blanking tool € When When a compo componen nentt is prod produce uced d with with one one single punch and die where the entire outer profile is cut in a single stroke the tool is called a blanking tool. € Blanki Blanking ng is the the opera operatio tion n of cutti cutting ng flat flat shapes from sheet metal. € The oute outerr area area of meta metall remain remaining ing after after a blanking operation is generally discarded as
Blanking Tool
waste. € Size of blank blank or product product is the size size of the die die & clearance clearance is is given on on punch. punch. € It is is a metal metal cutt cutting ing operat operation ion..
Piercing Tool Piercing involves cutting of clean holes with a resulting scrap slug. The operation is called die cutting and can also produce flat components where the die, the shaped tool, is pressed into a sheet material employing a shearing action to cut holes. This method can be used to cut parts of different sizes and shapes in sheet metal, leather and many other materials. Piercing tool
Cut off tool Cut off operations are those in which a strip of suitable width is cut to length in a single operation. Cut-off tools can produce many parts. The required length of strip can be cut off for bending and forming operations using this tool.
Cutoff tool
Types of press tools
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Parting off tool Partings are similar, in that a discrete part is cut from a sheet or strip of metal along a desired geometric path. The difference between a cutoff and a parting is that a cutoff can be nestled perfectly on the sheet metal, due to its geometry. With cutoffs, the cutting of sheet metal can be done over one path at a time and there is practically no waste of material. With partings, the shape can not be nestled precisely. Partings involve cutting the sheet metal along two paths simultaneously. Partings waste a certain amount of material, that can be significant.
Trimming tool When cups and shells are drawn from flat sheet metal the edge is left wavy and irregular, due to uneven flow of metal. This irregular edge is trimmed in a trimming die. Shown is flanged shell, as well as the trimmed ring removed from around the edge. While a small amount of Material is removed from the side of a component in trimming tool.
Shaving tool Shaving removes a small amount of material around the edges of a previously blanked stampings or piercing. A straight, smooth edge is provided and therefore shaving is frequently performed on instrument parts, watch and clock parts and the like. Shaving is accomplished in shaving
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Trimming Tool
Bending tool Bending tools apply simple bends to stampings. A simple bend is done in which the line of the bend is straight. One or more bends may be involved, and bending tools are a large important class of press tools.
Forming tool Forming tools apply more complex forms to work pieces. The line of bend is curved instead of straight and the metal is subjected to plastic flow or deformation.
Drawing tool Drawing tools transform flat sheets of metal into cups, shells or other drawn shapes by subjecting the material to severe plastic deformation. Shown in fig is a rather deep shell that has been drawn from a flat sheet.
Bending Tool
Types of press tools
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This type of Press tool is used to perform only one particular operation therefore classified under stage tools.
Progressive tool A progressive tool differs from a stage tool in the following respect: in a progressive tool the final component is obtained by progressing the sheet metal or strip in more than one stage. At each stage the tool will progressively shape the component towards its final shape, with the final
Drawing Tool
stage normally being cutting-off.
Compound tool The compound tool differs from progressive and stage tools by the arrangement of the punch and die. It is an inverted tool where blanking and piercing takes place in a single stage and also the blanking punch will act as the piercing die.
Combination tool In a combination tool two or more operations such as bending and trimming will be performed simultaneously. Two or more operations such as forming, drawing, extruding, embossing may be combined on the component with various cutting operations like blanking, piercing, broaching and cut off takes place- it can perform a cutting and non cutting operations in a single tool.
General Press tool Construction The general press tool construction will have following elements: € Shank: It is used to locate the press tool in press for alignment purpose. € Top Plate: It is used to hold top half of the press tool with press slide. € Punch Back Plate : This plate prevents the hardened punches penetrating into top plate. € Punch Holder: This plate is used to accommodate the punches of press tool. € Punches : To perform cutting and not cutting operations either plain or profiled punches are used. € Die Plate: Die plate will have similar profile of the component where cutting dies usually have holes with land and angular clearance and non cutting dies will have profiles. € Die Back Plate:This plate prevents the hardened Die inserts penetrating into bottom plate. € Guide Pillar & Guide Bush : Used for alignment between top and bottom halves of the press tools. € Bottom plate:It is used to hold bottom half of the press tool with press slide. € Stripper plate: it is used to strip off the component from punches. € strip guides: It is used to guide the strip into the press tool to perform the operation.
Types of press tools
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Cutting force in Press tool In general cutting force (CF) can be calculated using formula: CF =L x S x •max cutting force will be in Newton(N) Where, L = Cut length in mm,(perimeter of profile to be cut) Ex: 40 mm square to be cut will have cut length of 160 mm S = Sheet metal thickness in mm, •max = Maximum shear strength of sheet metal MPa
Stripping Force
Press tool
Stripping force will be usually 10 to 20 % of cutting force.
Press Force Press force will be cutting force with stripping force Press Force = Cutting force + Stripping force
Fits in Press Tools € Punch holder and Punches =H7/k6 € Punch and Stripper = H7/g6 € Guide Pillar and Guide bush = H7/g6 € Guide bush and Top plate = H7/p6 € Guide pillar and bottom plate = H7/p6 € Dowel and plate = H7/m6
References [1] Cyril Donaldson, George H LeCain, V C Goold, Tool design 3rd edition, Tata McGraw-Hill Education, New Delhi.
Article Sources and Contributors
Article Sources and Contributors Types of press tools Source: http://en.wikipedia.org/w/index.php?oldid=622315518 Contributors: 220 of Borg, Alan Liefting, Altaƒr, AsceticRose, Biscuittin, DoctorKubla, Ekabhishek, Gravuritas, HMSSolent, JaconaFrere, Jim1138, Katharineamy, KylieTastic, Magioladitis, Mild Bill Hiccup, Penfold20, Pinethicket, PrabhakarPurushothaman, Rasika251, Rich Farmbrough, SchreiberBike, Vieque, 37 anonymous edits
Image Sources, Licenses and Contributors File:Blanking Tool.png Source: http://en.wikipedia.org/w/index.php?title=File:Blanking_Tool.png License: Creative Commons Zero Contributors: PrabhakarPurushothaman, Sfan00 IMG File:Piercing tool.png Source: http://en.wikipedia.org/w/index.php?title=File:Piercing_tool.png License: Creative Commons Zero Contributors: PrabhakarPurushothaman, Sfan00 IMG File:Cutoff tool.png Source: http://en.wikipedia.org/w/index.php?title=File:Cutoff_tool.png License: Creative Commons Zero Contributors: PrabhakarPurushothaman, Sfan00 IMG File:Trimming Tool.png Source: http://en.wikipedia.org/w/index.php?title=File:Trimming_Tool.png License: Creative Commons Zero Contributors: PrabhakarPurushothaman, Sfan00 IMG File:Bending_tool.png Source: http://en.wikipedia.org/w/index.php?title=File:Bending_tool.png License: Creative Commons Zero Contributors: PrabhakarPurushothaman, Sfan00 IMG File:Drawing_tool.png Source: http://en.wikipedia.org/w/index.php?title=File:Drawing_tool.png License: Creative Commons Zero Contributors: PrabhakarPurushothaman, Sfan00 IMG File:Press_tool.png Source: http://en.wikipedia.org/w/index.php?title=File:Press_tool.png License: Creative Commons Zero Contributors: PrabhakarPurushothaman, Sfan00 IMG
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