manufacturing-processes_deep drawing is a sheet metal forming process in which a sheet metal blan

8/13/2019 Manufacturing-Processes_Deep Drawing is a Sheet Metal Forming Process in Which a Sheet Metal Blan

1/5

Deep drawing

It is a sheet metal forming process in which a sheet metal blank is radially

drawn into a forming die by the mechanical action of a punch. It is thus ashape transformation process with material retention. The flange region(sheet metal in the die shoulder area) experiences a radial drawing stress anda tangential compressive stress due to the material retention property. Thesecompressive stresses (hoop stresses) result in flange wrinkles (wrinkles ofthe first order). Wrinkles can be prevented by using a blank holder, thefunction of which is to facilitate controlled material flow into the die radius.

Process

The total drawing load consists of the ideal forming load and an additionalcomponent to compensate for friction in the contacting areas of the flangeregion and bending forces at the die radius. The forming load is transferredfrom the punch radius through the drawn part wall into the deformationregion (sheet metal flange). ue to tensile forces acting in the part wall, wallthinning is prominent and results in an uneven part wall thickness. It can beobserved that the part wall thickness is lowest at the point where the partwall loses contact with the punch, i.e. at the punch radius. The thinnest part

thickness determines the maximum stress that can be transferred to thedeformation !one. ue to material volume constancy, the flange thickensand results in blank holder contact at the outer boundary rather than on theentire surface. The maximum stress that can be safely transferred from the

punch to the blank sets a limit on the maximum blank si!e (initial blankdiameter in the case of rotationally symmetrical blanks). "n indicator ofmaterial formability is the limiting drawing ratio (# $), defined as the ratioof the maximum blank diameter that can be safely drawn into a cup withoutflange to the punch diameter. etermination of the # $ for complexcomponents is difficult and hence the part is inspected for critical areas forwhich an approximation is possible.

%ommercial applications of this metal shaping process often involvecomplex geometries with straight sides and radii. In such a case, the termstamping is used in order to distinguish between the deep drawing (radialtension&tangential compression) and stretch&and&bend (along the straightsides) components.
http://en.wikipedia.org/wiki/Sheet_metalhttp://en.wikipedia.org/wiki/Metal_forminghttp://en.wikipedia.org/w/index.php?title=Formability&action=edit&redlink=1http://en.wikipedia.org/wiki/Sheet_metalhttp://en.wikipedia.org/wiki/Metal_forminghttp://en.wikipedia.org/w/index.php?title=Formability&action=edit&redlink=1


2/5

Variations

eep drawing has been classified into conventional and unconventional deep drawing. The main aim of any unconventional deep drawing process is

to extend the formability limits of the process. 'ome of the unconventional processes include hydromechanical deep drawing, ydroform process," uadraw process, *uerin process, +arform process and the hydraulic deepdrawing process to name a few.

The +arform process, for example, operates using the principle of rubber pad forming techni ues. eep&recessed parts with either vertical or sloppedwalls can be formed. In this type of forming, the die rig employs a rubber

pad as one tool half and a solid tool half, similar to the die in a conventionaldie set, to form a component into its final shape. ies are made of cast light

alloys and the rubber pad is .-& times thicker than the component to beformed. /or +arforming, single&action presses are e uipped with diecushions and blank holders. The blank is held against the rubber pad by a

blank holder, through which a punch is acting as in conventional deepdrawing. It is a double&acting apparatus0 at first the ram slides down, thenthe blank holder moves0 this feature allows it to perform deep drawings (12&324 transverse dimension) with no wrinkles.

Industrial uses of deep drawing processes include automotive body andstructural parts, aircraft components, utensils and white goods. %omplex

parts are normally formed using progressive dies in a single forming press or by using a press line.

Workpiece materials and power requirements

'ofter materials are much easier to deform and therefore re uire less force todraw. The following is a table demonstrating the raw force to percentreduction of commonly used materials.


3/5

Drawing force required for various materials and reductions [kN] 567

Material

Percent reduction

39 !3 !" #$

"luminium 88 2 1 6

9rass : 13 - 68

%old&rolled steel : 3- 61 8

'tainless steel 66 ;2 3 18

%ool materials


4/5

()eet metal

it is simply metal formed into thin and flat pieces. It is one of thefundamental forms used in metalworking , and can be cut and bent into avariety of different shapes. %ountless everyday ob=ects are constructed of thematerial. Thicknesses can vary significantly, although extremely thinthicknesses are considered foil or leaf , and pieces thicker than 6 mm(2. - in) are considered plate .

'heet metal is available as flat pieces or as a coiled strip. The coils areformed by running a continuous sheet of metal through a roll slitter .

The thickness of the sheet metal is called its gauge . The gauge of sheet metalranges from 12 gauge to about 8 gauge. The higher the gauge, the thinner themetal is.

There are many different metals that can be made into sheet metal, such asaluminum , brass , copper , steel , tin , nickel and titanium . /or decorative uses,important sheet metals include silver , gold , and platinum .

'heet metal has applications in car bodies, airplane wings, medical tables,roofs for building and many other things. 'heet metal of iron and othermateriales with high magnetic permeability , also known as laminated steelcores , has applications in transformers and electric machines . istorically,an important use of sheet metal was in plate armor worn by cavalry , andsheet metal continues to have many decorative uses, including in horse tack .
http://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalworkinghttp://en.wikipedia.org/wiki/Metal_leafhttp://en.wikipedia.org/wiki/Metal_leafhttp://en.wikipedia.org/wiki/Structural_steelhttp://en.wikipedia.org/wiki/Roll_slittinghttp://en.wikipedia.org/wiki/Sheet_metal_gaugehttp://en.wikipedia.org/wiki/Aluminumhttp://en.wikipedia.org/wiki/Brasshttp://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Tinhttp://en.wikipedia.org/wiki/Nickelhttp://en.wikipedia.org/wiki/Titaniumhttp://en.wikipedia.org/wiki/Silverhttp://en.wikipedia.org/wiki/Goldhttp://en.wikipedia.org/wiki/Platinumhttp://en.wikipedia.org/wiki/Permeability_(electromagnetism)http://en.wikipedia.org/wiki/Transformer#Constructionhttp://en.wikipedia.org/wiki/Transformer#Constructionhttp://en.wikipedia.org/wiki/Transformer#Constructionhttp://en.wikipedia.org/wiki/Electric_machinehttp://en.wikipedia.org/wiki/Plate_armorhttp://en.wikipedia.org/wiki/Cavalryhttp://en.wikipedia.org/wiki/Horse_tackhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalworkinghttp://en.wikipedia.org/wiki/Metal_leafhttp://en.wikipedia.org/wiki/Metal_leafhttp://en.wikipedia.org/wiki/Structural_steelhttp://en.wikipedia.org/wiki/Roll_slittinghttp://en.wikipedia.org/wiki/Sheet_metal_gaugehttp://en.wikipedia.org/wiki/Aluminumhttp://en.wikipedia.org/wiki/Brasshttp://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Tinhttp://en.wikipedia.org/wiki/Nickelhttp://en.wikipedia.org/wiki/Titaniumhttp://en.wikipedia.org/wiki/Silverhttp://en.wikipedia.org/wiki/Goldhttp://en.wikipedia.org/wiki/Platinumhttp://en.wikipedia.org/wiki/Permeability_(electromagnetism)http://en.wikipedia.org/wiki/Transformer#Constructionhttp://en.wikipedia.org/wiki/Transformer#Constructionhttp://en.wikipedia.org/wiki/Transformer#Constructionhttp://en.wikipedia.org/wiki/Electric_machinehttp://en.wikipedia.org/wiki/Plate_armorhttp://en.wikipedia.org/wiki/Cavalryhttp://en.wikipedia.org/wiki/Horse_tack


5/5

manufacturing-processes_deep drawing is a sheet metal forming process in which a sheet metal blan

Documents