Rolling Processes in Metalforming PDF

ROLLING -Products: Flat, structural, rings, discrete parts, welded and seamless pipes. deformation process in whichthethickness oftheworkis reduced compressiveby How it is done: Metal is passed between two roller that are spaced apart less than the thickness of the part. The part is then d...

ROLLING -Products: Flat, structural, rings, discrete parts, welded and seamless pipes. deformation process in whichthethickness oftheworkis reduced compressiveby How it is done: Metal is passed between two roller that are spaced apart less than the thickness of the part. The part is then deformed into that thickness, though it springs back gg a tiny amount after exiting the rolls basicprocessis flat s starts frommetalingot Picture i whichisheatedintheprocessofsoakingusingafurnace soaker rolling an or itis Coldrollingis IoutI iining s tied t.fi for figto bynotrolling prepare sheet hotrolledmetalis generally metalprocess strengthensthe fitp s ignterforefathers thickness Roll bending: occurs due to forces in the workpiece; the force pushes the rolls outwards and produces the deflection; this can cause thickness of the material to vary; to remedy this, use either backing rolls or barrels -Material is sliding on the roller. One no slip point (neutral). No slip point: as workpiece goes through the rolls and changes thickness, there will be a bit of slipping between the rolls and the workpiece and at one point, there will be no slippage. This is the no slip point. This is relevant when discussing friction in rolling operations. Picture FIAT ROLL squeezedbetweentwo rolls pointwhere work velocity isequal to rolvelocity p own asneatal Iff rollingalso offffffeduced increasesworkwidth -Forces against roll: Average true stress x contact area. Average true Stress: the strength of the part as it undergoes deformation that is going to increase its strength in the plastic region. As the reduction per pass increases, more deformation takes place, and the average true stress goes up. Contact area: the surface contact of the roll which is the width of the workpiece times the arc of the roll which is in contact with the plate. As the roll diameter increases, there is less contact area, thus less force. thantheothersidesofytthfyntfff.ms the Friction on the entrance side ofthe noslip pointisgreater pulls -Force reduction by: Smaller rolls (less contact area), reducing friction, smaller reduction, elevated temperature rolling. hot rolling ratherthantoldreducingrollingspeed -Compensation for roll deflection to produce flat stock: Geometric (camber), support rolls. Lower forces means lessfriction whichmake it easierfor  material to roll -Wrought structure: Flow lines, stringers. Microstructure- changes in the grain structure of cast or of large grain wrought metals occur during hot rolling. If cold rolling a metal with non uniform grains, it produces a wrought product with large grains. Whereas if hot rolled, the metal is able to recrystallize and form new uniform grains, increasing its strength and ductility Flow lines- lines or filaments of slag, oxides, or sulfides that are left in the final product after the production process Stringers- lines or filaments of slag, oxides, or sulfides that are left in the final product after the production process -Pack rolling: two films of aluminum foil together. -Low carbon steel will form Lueder’s bands and requires temper rolling. -Leveling rolls are used to improve flatness. Typically when it comes off a roll and it is needed flat for the application -Defects: Wavy edges from a thicker center portion (stretches outside more), cracks from insufficient ductility. Alligatoring is produced from uneven rolling, defects in middle of ingot, or poor ductility -Residual stresses (cold worked) in material. Picture -Rolling mills: rollingmillconfigurationsareavailable todealwithvariety ofapp Various problems finffynical By 2 high: non reversing where the work move in only one direction 2 high reversing: has the material going through in one direction, the rolls are adjusted closer and the rotation direction is reversed and the workpiece is passed back and forth many times until final geometry is achieved disadvantage isthe momentum 3 high (reversible): similar to reversing accept for I doesn’t need to be stopped and angular neededtoraise lower reversed directionremains thesame workbecomesmorecomplicatedas aelevator systemis 4 high and Multiple: simply provide backup forces to the rolls thework Astheiraremanyadvantagestousingtoreducingrolling rollsareusedforthemainrolling biggerbacking diameter2 smaller Rolling mill lines: typically set up continuously such that as the material exits one rollssupportthat set of rolls it enters another one ftpytoEn g excessively -Tandem rolling: Rolls are in line. (4 high) line of rolls 8 8 8 -Ring rolling: Make contours and sizes with precision. Cover alternatives (casting, machining). Def: A bar or strip of the proper length is welded end on end to form the ring. Then it is rolled to form the desired cross section and thickness as shown. Pic Essentiallythick walled ringofsmaller diameter rolled is into athin with walledring diameter Larger nidKingfted -Thread rolling. Threaded rolling utilizes roller dies (one stationary and one moving) with threaded geometry to roll the thread onto the part. This process is economically sound and can be used to make fasteners. The difference between rolled and cut thread is that the rolling of the thread causes improved strength of the part, because of the cold work being done to it. Both cutting and rolling thread produce grain flow, but the grain flow produced from rolling is more favorable than from machining. Coldworking process I Shape rolling- passes being pressed into desired shape. Picture cross contoured Workis deformed bypassingthework sectionaccomplished reverseoffhe thathavethe desired throughrolls Hht inflatrollingapplytoshape concepts rolling shaperollingis accept morecomplicated requiresagradual rollsto several transformationthrough final achieve section cross Either Seamless pipe: Mannesmann process- It involves heating a solid steel billet, piercing it to create a hollow tube, elongating and reducing its thickness, and then sizing it to the final dimensions. This was developed in the 1880s Integrated mills- rolling mill that obtain their iron ore from iron ore reduction (tend to be very large) Minimills- rolling mills facility that uses scrap as raw material (smaller than integrated) ————————————————————————————————————————————— FORGING Forming largegroupofmanufacturingprocessesinwhichplastic isusedtochangethe shapeof deformation metalworkpieces Basic Process: metal is heated to a temperature where it is easy to deform, and then is struck with a hammer to change the shape. The workpiece continues to be struck until it is deformed into the desired shape. (Most forging is hot work) There is a material dependence for forging. Materials that have more ductility and lower strengths at elevated temperatures generally forge easier Forging shape examples: Horseshoes: through open die forging; connecting rods: through closed die forging and would have a flash; Flashless or precision die forging is similar to closed die forging, but without the flash with tighter tolerances Die Tool for used metaldeformationappliesstressesthatexceedyieldstrengthofmetal Open die: work is compressed between two flat dies, allowing the metal to flow without constraint in a lateral direction relative to the die surfaces -Limited geometric capability, but very simple tooling. -very simple dies in the shape of wedges, flats, and rounds are used to progressively shape the part -an advantage to open die forging is that the parts can weigh up to tons and the tooling is relatively simple and inexpensive -a disadvantage though is the significant amount of machining that needs to be done to the workpieces Closed die: more complex shapes; metal is placed between the dies and when the dies close, they surround the metal and force it to fill the die and assume the shape. A flash is used in this process as excess metal that is squeezed out relatively early in the process and as it surrounded by colder metal of the die, it cools down, becomes stronger and resist any more of the actual metal being pushed out to the parting line and forces it into the nooks and crannies of the die. The flash is trimmed of later. Precision die- forging is similar to closed die forging, but without the flash with tighter tolerances; dies produce better detail, but require more force to have the material flow into the cavity details mainlyusedwithgeometriesthatareusuallysimple symmetrical requireclose I Forging with or without flask: flashes forging requires that the amount of metal tolerances prepared for the workpiece must be more accurate in order for it to fully fill the mold and also meet the dimensional tolerances -Heat and hit –old days. Now forging processes are differenced by how they 1) compress (impact, continuous pressure), 2) temperature (low, high, isothermal) and 3) Tooling, (open die, closed die, precision die). -Comparison of microstructure between cast, forged, and machined from rolled block. In forged microstructure, the grain flow patterns can be seen. Forgings tend to have some anisotropy ( difference in the physical property of a certain material when measured along different axes.) Grain flow follows the outline of the component In machining, the grain flow is broken Picture maching Iffbroken broken -Cogging: forging operation used to reduce the thickness of a part and increase the length Picture Flashless forging: workpiece is completely contained within the die cavity and not flash is formed tastefonto Iep -Impression die forging: Picture closeddieforging themetal -the die surfaces contain a shape or impression that is imparted to the work during compression, thus constraining metal flow to a significant degree -Assumes the shape of the cavity in one or multiple steps. Will produce flash which then cools, strengthens (due to lower temperature) and forces the rest of the material in the cavity to fill up the cavity rather than flow out. contain the inverse the desired shape ofthepart closesto itsfinal positionflash is As die the beyondthediecavity formed bythemetalthatflows intothesmallgapbetweenthedieplates Noteflashmustbecutaway Sometimes severalblowsofdiemayberequired -Net shape forging, very little subsequent work required. -Heading or upset forging: to increase the cross sectional area of the part from a thinner workpiece. (bolts) Picture; Typeof opend ieforging In the production of small parts, a narrow bar or wire is introduced to a die. Once the part is located at the proper spot, the part is supported, upset forged and then pushed through and trimmed to the right length, and then starting the cycle again upsetforging reducestheheightof thework increasesitsdiameter ofbolts usedtomaketops -Piercing: Making an indentation in the part. -Isothermal forging: Dies are heated to the working roll temperature of the material, so it does not cool down. One step process. Tools made of high temperature alloys (Mo, Ni). In addition, this forging is a squeezing process, the main advantage is that the workpiece does not cool down during the process and is possible to obtain much more deformation and get closer to a near net shape part. The disadvantage includes the need for dies to made for superalloy or refractory materials which make them much more expensive as well the infrastructure needed to heat the dies and much hotter operating environment, this type of forging typically reserved for difficult to forge materials, like titanium and superalloys like atubeorsolid - Swaging: operation that is usually used to reduce the diameter of a hollow piece mÉipÉe such as a pipe. However, some pieces are opened up by working them internally. In the process, the end to be reduced is turned into a series of swaging to be performed a to tapered Crieff -accomplished by a means of rotating does that hammer a workpiece radially inward to taper it as the piece is fed into the dues -Swaging of tubes without a mandrel increases the wall thickness in the die gap -a mandrel is used to control the shape and size of the internal diameter of tubular parts that are swaged -Rotary swaging: a series of rollers are used to spin around the workpiece while a die closes progressively until the desired diameter is attained (Picture), the work is rotated as it feeds into hammering dies - die design: -uniform flow of metal is desired throughout the entire part -ribs should be short and wide -draft and radii should be generous small -flash clearance should be allowed radiitendsto limitmetalflow -lubricant application should be considered -Trimming/punching tool set should be included Closed die parts will typically have some flash. As some volume is required to justify the cost of a closed tool, typically trim dies to efficiently handle larger amount of forgings -Preshaping so all the material flows about the same amount. -Draft: Internal 7-10 degrees, External 3 to 5 degrees. -Flash: into a gutter, thickness: 3% of maximum forging thickness, land width 3-5 times flash thickness. -Radii and Draft: more generous in forging than in casting for closed die forging -Lower, flatter ribs for closed die, tend to be short and wide as well -Parting line: Flat is best, along widest portion of part. -Die materials: Tool steels (review performance needs)., the workpiece material and temperature will determine the die material -Lubricants: Lubricate, thermal barrier, parting agent. -Forgeability: Ability to be forged without cracking. Barrel compression, twist test. -Defects: Generally, design for the same amount of movement for entire metal mass. Surface cracks (as in barrel compression, caused by if the center fills before the outside parts in the die), web buckling (laps, die cavity filling, happens when the outside sections of the shaped part fill first) material flow under filled cavities (shearing material), end grain exposure (to surface). -Equipment: -Forging Presses- a machine that shapes metal into a new form by applying pressure between two dies, typically have source of motion, a place to position the dies with at least on being movable, and a rigid frame enough for the forces being applied -slow loading (Hydraulic, mechanical, screw); Hammers, impact loading (gravity drop, power drop, counterblow (both sides)). Picture Hammers operate an impact me byapplying the against made series drophammer loading Iging p attachedtoram upperportion anvil lowerattachedto MechanicalPresseccentricscranks or knuckle joints -Process: 1) prepare a clean slug of proper weight. 2) Heat (if necessary). 3) Add lubricant. 4) Forge and trim. 5) Machine if necessary. 6) Straigtening and Heat treating (if necessary). 7) Inspection. -Dies: Get necessary geometry in a suitable material for hi temp and type of loading. -Economics: Sensitive to lot size (due to tooling costs). Increments in size change cost in a lower proportion. Unit costs in forging: Picture For large quantities, forging is more economical, sand casting is more economical process for fewer than 20,000 pieces ————————————————————————————————————————————— EXTRUSION AND DRAWING Extrusion: Bulk forming, push material through hole. Wire drawing: bulk forming, pull material through hole. -Extrusion is the compression process of pushing material through a die opening of desired shape; typically produces long and uniform cross sections such as ladders sides, whiteboard trim, and eraser shelf; inexpensive way to produce components that properly accommodate to it Advantages: variety of shapes can be made, grain structure and strength properties are enhanced, fairly close tolerances, little or no wasted material billet the of Picture Hot involvespriorheating to atemp above recrystallizationtemperature -Variables in extrusion: a) Temperature (hot, cold), b) Ram speed (uniform, impact) speedcold extrusion high Impact extrusion: or cold extrusion, it is a hybrid of forging and extrusion, the workpieces is a specific part where a specific shape Is wanted -One advantage of cold working is the lack of waste material c) Extrusion die type (direct, indirect, lateral, hydrostatic) Picture for all Direct Extrusion: most commonly used type, plastic material is pushed through a hole of the desired shape and then the material assumes this shape; typically made up of 8 parts: extrusion, die backer, die, billet, dummy block, pressing ram, container liner, container body blockofmetal -Due to the nature of the process, the only materials that can be used are those that are available in the proper billet geometry for a given piece of equipment. This limits the choice of materials -requires a lot of force due to friction, although a dummy block can be used to remove the oxide layer that is created when hotworking extrusion Indirect extrusion: the is opposite of direct extrusion, where the die is forced into the metal. The advantage this gives is that it requires less force than direct extrusion (which requires a significant amount due to side wall friction as the billet slides against each other) Hydrostatic extrusion: similar to direct extrusion except that the extruding force on the metal is provided by a fluid that is pushed with the ram -the advantage to this is that different billet sizes can be used for the same machine; disadvantage would be that seal maintenance at those pressure is very difficult fric tionis alsoreducedcomparedtodirectextrusion ramforceissignificantlylower this ofdirect d) Ratio=Ao/Af (typical values 10-100) agtype Af= extrusion pressure times the cross sectional area Ao= area; Note: area, die angle, reduction in cross section, extrusion speed, billet temp., and lubrication affect the pressure Actual formula; has a k constant: F= Aox *k*ln(Ao/Af) Hydrostatic nitialAreaofbillet Lateral Areaofbillet final -Flow pattern: if tensile strength of the material is exceeded, internal cracks or chevron cracks can be seen in the metal flow Picture Types of metal flow: low friction/ indirect extrusion, pattern obtained at high friction in the bills’ chamber Dead zone- an area where metal does not flow lowtriction nigh -Generally speaking, low tool costs. -Die: dies have different configurations as in the extrusion process; they can have a angled entry exit point to or be shaped into different shapes for the entry ways. I.E no ferrous metalsthat metals, workpiece is typically a square die. Die for ferrous metals need and entry angle to minimize the dead zone i men ymetana -Spider die: used to produce hollow shapes. For example, the interior of a pipe will be produced by the mandrel that will effectively pierce the billet to produce the hole. The mandrel is held in place with spider legs (thins supports to the mandrel) Picture -what happens if lubricants were used in this process? The lubricants can get into the areas where the metal was separated and prevent rewelding -Tool steel, sometimes coated with ceramic coatings for wear protection Generally speaking, low tool costs. Tools themselves for this application tend to be relatively thin; use a backer die to provide structural support Generally speaking, low costs. -Geometry: Entry angle (0 for nonferrous), land, back relief, support block -Defects: -Surface cracking (from final workpiece temperature being too high from starting to hot, or processing too fast). Solution: lower temperatures and/or speeds -Pipe: metal from dead zone channels surface oxides to the center of extrusion. Solution- change geometries to change metal flow, clean the outside surface billet if surface particles reach the center they won’t have oxides useofa of socialite fi dummy -Internal cracking: From stresses formed around plastic deformation zones. Tendency towards chevron cracking increases if the two plastic zones do not meet -Bamboo effect: the workpiece temporarily sticks on the land of the die; then material compresses behind and pushes it forward again. Solution: change parameters to prevent sticking tofind causeshighdie crackinternaldefectthatistypicallyhard angle C Eft Imitated -Example cross sections: Picture DRAWING: -Process: Pull material through die to shape the product, typically used to produce bars, wire and pipe crosssection -Bundle drawing. ofpartisreducedwhenpulledthroughthedie Reliesontensionforces -Die: Picture Tooling: -Geometry: Bell (entrance), approach angle, land, back relief angle. -Profile drawing possible (sequential dies). -Material: Tool Steel, carbides, with coatings.  Wire drawing: Picture If the force required to pull the wire is greater than the tensile carrying ability of the wire, then the wire will snap. That is why it is necessary to have multiple passes. Draft difference Wiredrawingtermusedfor smalldiameter bar rodstock etweeninitial itis acontinuousdrawingoperation finalstockdiameters becauseofthe long productionruns thatareachievedwiththewirecoils Wineisdrawnfromcoilsconsisting ofseveralhundredfeetowf ine ispassed throughaseriesofseveraldies for Bardrawing used largediameterrods dth.roughoned.ieopening Singh -Lubrication: Wet drawing (immersed in lubricant), Dry drawing (wire is coated with solid lubricant such as soap), coating (coating with a soft metal, ie tin), ultrasonic vibration during the process at the die. -Geometries: wire, pipe (no mandrel, floating plug, stationary and moving mandrels). -Speeds: 1-2.5 m/s thick sections 50 m/s for fine wire. -Reductions/pass: Near zero to 45% (thinner materials take smaller reductions per pass) ————————————————————————————————————————————— SHEET METAL BENDING Holesaremade -Incoming material Blanking (punching, slitting, etc.) Individual operations inmetalthroughspider (punching, bend, etc.) Secondary (Welding, machining, etc.). Blanking and individualoperations can be done in one setup with progressive or compound dies. or mandrel Sheetmetalworkingincludes formingoperationsperformedon cutting -Shearing:relatively Picture thinsheets ofmetal between6.4mm 6mm -Process: Sheet metal shearing consists of pushing one portion of the metal with a punch or a blade against a anvil or die that supports the rest of the metal. Metal first responds by first having a little bit of penetration and then through mechanical deformation ripping off -Clearance: A certain amount of clearance is needed between the punch and the die; this clearance depends on the material, hardness, and the thickness. Typical die thickness: 2-10% of thickness. As the clearance increases, the material tends to be pulled into rather than be sheared -Burr results in sheared edges. Often needs to be removed. Can be prevented by restraint attention tEfnc sk ieiteinp work plasticdeformation 2 punchbegins compresses penetratesworkcausing 3 punch smoothcutsurface 4 fractureisinitiatedatopposingcuttingedges Three basicformsofcutting shearing blanking punching “fine blanking”- involves cutting of the sheet metal along a closed outline in a sinigle step to separate the piece from the surrounding stock Punching: similar to blanking, but it produces a hole, and the spectated piece (the hole) is the scrap of slug -Force=constant x sheared area x tensile strength of material. -Force=0.7 x (perimeter x thickness) x UTS of material Punching/blanking: which part do you keep?- If the punched part is discarded, then it is punching, if the punched part is kept, then it is blanking Picture -Perforating- simultaneously punching a pattern of holes, parting- below , notching- cutting out a portion of metal from the side of sheet or strip, lancing, seminotching- removes a portion of metal from the interior of the sheet -Slitting: knifes produce a cut into the sheet metal that is not sufficient to cut a hole in the workpiece. Like a can opener Nibbling: Progressive shearing by one shear at a time. (progressive punching) Scrap management: Nesting of parts: parts are arranged in the sheet to use as much of the sheet as possible Residual value Tailor welded blanks: Efficient way to produce parts, lighter material is need thus reducing costs. Also requires less galvanizing. Also, better nesting. Cutoff: shearing operation in which blanks are separated from a sheet metal strip by cutting opposite sides of the part in sequence Parting: involves cutting a sheet metal strip by a punch with two cutting edges that match opposite sides of the blank Drawback: welding operation.  Shaving: Improve sheared edge. Secondary operation. Shearing and shaving die. Beveling of punches/dies: Controls portion of material being sheared vs. stroke location. Reduces maximum force. Punches/dies dull faster. Compound dies: In a washer, they pierce center hole and cut washer from strip in same motion (same time,), tend to be very complicated and are relatively expensive due to all the special notions they need to perform. Progressive dies: One step they pierce the center of the strip, on the next step the washer is blanked out of the die (sequential).Can make complex parts as long as they are sequential. Progressive dies can use many off the shelf components especially for shearing applications and this makes them more economically attractive Other cutting methods are available. -Sheet metal properties: Ductility (tensile elongation): Higher is better. More deformation can take place. Strain hardening: Lower is better. Forming force increases slower. Necking tendency: Lower is better. Can form more with ‘predictable’ behavior. Anisotropy: Anisotropy refers to different properties in different directions of the material. Sheet metal has anisotrophy because bending in different directions can yield different results -Normal Anisotropy: R (normal anisotropy)F= εw(width strain)/ εt (thickness strain) Earing defects are caused by excessive anisotropy of the sheer metal -Formability tests: Cupping: uniaxial, or equal biaxial. Forming limit diagrams: for complex stresses (circles drawn on part) -Bending: When a piece of sheet metal is bent, there is a side that in compression and one in tension. There is a line between both those sections that does not experience stress called the neutral axis arounda straight Bending radius vs ductility graph: Picture straining ofmetal operation the axis duringthebending metalontheinside ofthe plane neutral metal the is compressedwhile is outside stretched Fine FIRE Bend allowance: if the bend radius is small relative to stock thickness, the metal tends to stretch during bending -bending allowance is the length of the neutral axis before bending to account for stretching of the final bent section ; Lb=alpha (R+kT) Where Lb=Bend allowance Alpha=Internal bend angle (complete roll over=180, ¼ rollover =45) R=Internal bend radius k=Constant (R2T, k=0.5) T=Thickness. Bending vs rolling direction: if the bends are made in the direction of the rolling, cracks are more likely to develop. To avoid, bend the other way. If bends need to be made 90 degrees from each other, then the part should be offset at 45 degrees so no bend is parallel to the direction of rolling Minimum bend radius (prior to failure), depends on thickness, ductility. Springback: a small amount of elastic recovery that always occurs in metals once the force applied is removed. Sometimes it is necessary to overbend to so that the metal will be at the correct angle. Bending types: Press bending: Air, bottoming die, Air bending: the shape is determined by how deep the stroke goes into the die. If the stroke is deeper, than the internal angle of the workpiece is smaller. Can produce more geometries the bottoming Bottoming die: the workpiece is in full area contact with the dies and the shape is determined by the shape of the dies minus the springback. Can produce better product with tighter tolerances then air bending. Picture Roll bending: used to obtain a specific radius on a workpiece. This is obtained by the relative alignment of the three rollers and the clearances between them. Picture wiping die, multiple step die,: Picture Roll forming: is used to change the cross section of sheet metal strips to a complex cross section informing involvebendingratherthancompressive is not arollingopertion work usedtoproducelongsections counteract to Used springback Drawbeads: protrusions from one die into the next whose purpose is to slow down the rate of sheet metal displacement along the sides. Thus more metal will be pulled from the corner regions to make the shape -If drawbeads were not used, the difference in metal pulled from the sides and corner would be greater, thus forcing to have a larger blank (more expensive0 to produce the same shape Picture Flanging: is the formation of a perpendicular edge on the part, essentially a bending operation, in simple bending stress. hemming & seaming: , roll forming (above). Pic for all essentially is edge fworkpiece bent90 angle Tube bending: -Main challenge- Keep tube from collapsing: external dies with/without internal mandrel. -Solution: Utilize outside elements (blocks pressure bars, clamps, wiper shoe) that have a groove that matches the outside diameter of the tube, keeping it from opening in ant direction Picture -Forming & Drawing: -The material will see metal displacement from the original shape, chaging thicknesses and geometries significantly iDrawing is asheetmetalformingoperationused tomakecupshapedbox shaped or othercomplex turned concaveparts It is performed apieceofsheetmetaloveradiecavity thenpushing metalintoopening byplacing the withapunch Stretch forming: metal is stretched over a form of the desired shape; aluminum skins for aircrafts are typically made through this Picture sheetmetaldeformation process in whichthesheetmetal is intentionallystretch simultaneously benttoacheiveshapechange Deep drawing: the process of forming sheet metal by using a punch to radially draw the metal into a forming die; Parts-Die, punch, blankholder, stipper ring -Stresses in deep drawing: as the metal is being pushed down, the area of the blank is too large to form the perimeter of the final product. Thus, the metal needs to be displaced and this results in the outside portions of the blank being deformed into increased length of the cup -Drawing Ratio: DR= BD/PD DR- drawing ratio, PD- punch diameter, BD- Blank diameter 2 pics one of deep and stress Very sensitive to anisotropy Ironing: passed through a punch and die system to increase the length of the workpiece by thinning the side walls. Thickness reduction. Embossing: Pressing between two shallow closed dies. Two dies are matched together to push the sheet metal into the other and form the desired design Rubber forming: Rubber pushes material against shape of die. -Can reduce costs (uses one die) -The principle is that die pushes the sheet metal into the rubber and the rubber will push back, forcing the sheet metal to assume the shape Spinning: part is placed on a mandrel that works as a tool to provide the shape. Both are placed on a lathe and the mandrel and the workpiece are spun together. The forming tool is then used to push the blank into the mandrel until the final shape is attained Picture ametalformingprocess inwhichan shaped axiallysymmetricpartisgradually overa mandrelorformbya means ofa toolorroller.Thetoolorrollerapplies rounded a verylocalizedpressuretodeformthework byaxial radialmotions oversurfaceofthepart mandrel Essentially sheet placed metaling isonarotating thesheetmetalwhich apressureisappliedbyatoolon mandrel pushes itontothespinning Superplastic forming: allows for the stretching of product to much longer levels possible by simple stretching. This is used specifically for products that require high stiffness and low weight that can be achieved only with welded metallic structures Explosive forming: hydroforming process- fluid is compressed suddenly and violently through an explosive charge Honeycomb production: structures used for high stiffness and low weight. Example is cardboard Picture