A given material (shapeless or a simple geometry) Primary shaping processes Metal forming processes Metal cutting processes Metal treatment processes A complex geometry (shape, size, accuracy, tolerances, appearance, Properties) Casting, melt extrusion, die casting, etc. Rolling, extrusion, forging, bending, drawing (plastic deformation) Sawing, turning, milling (by removing metal) Heat treatment, surface hardening (unchanged in shape, changed in properties) Joining processes Metallurgical joining : welding, Mechanical joining : riveting, shrink fitting, assembly
Material type Forming temp. Massive forming processes (Bulk forming processes) : forging, extrusion, rolling, drawing Large plastic deformation, appreciable change in shape or cross section, The portion of permanent deformation >> elastic deformation Elastic deformation is negligible Sheet forming processes : deep drawing, stretch forming, press forming Sheet, changes in shape, not in section, permanent=elastic, e/recovery Cold forming processes : room temperature Hot forming processes : above the recrystallization temp. Most materials behave differently under different temperature condition ; [cold forming] Y.S. increases with an increase of strain ; [hot forming ] Y.S. increases with an increase of strain rate Attractive points in case where the part geometry is of moderate complexity in case where the production volume are large in case where tooling costs per unit product should be kept low
Closed die forging with flash a billet is formed (usually hot) in dies (usually with two halves) the excess of the material is extruded through a restrictive narrow gap
Closed die forging without flash in this process, a billet with carefully controlled is deformed by a punch in order to fill a die cavity without any loss of material, the punch and the die may be made of one or several pieces
Coining process coining is a closed die forging (usually called restriking) all surfaces of the work are confined or restricted resulting in well-defined imprint of the die on the workpiece
Coining process
Open die forging is a hot forming process the metal is shaped by hammering or pressing between flat or simple contoured dies. most of shafts can be manufactured by this process
Open die forging is a hot forming process the metal is shaped by hammering or pressing between flat or simple contoured dies. most of shafts can be manufactured by this process
orbital forging shapes parts by incrementally forging a slug between an rotating upper die and a non-rotating lower die the lower die is raised axially toward the upper die, which is fixed axially
Figure 5. Comparison between classical and orbital forging w i t h d i f f e re n t a x l e ro t a t i o n a n g l e s ( n u m e r i c a l a n a l y s i s )
Through the upsetting process, the cross sectional area in increased (heading)
A punch compresses a billet (hot or cold) confined in a container the billet material flows through a die in the same direction as the punch
a moving punch applies a steady pressure to a slug confined in a closed die it forces the metal to flow around the punch in a direction opposite the punch direction
a hot or cold forming process for reducing the cross-sectional area this process uses rotating rolls the rolled material (plate) elongates and spreads at the same time
Shape rolling is a cold or hot forming process for reducing as well as shaping the cross section of the metal the metal passes through a series of rotating sets of rolls with grooves
the process of reducing the cross section and the diameter of a tube
a process where a hollow circular blank is formed into a ring a main roll presses on the outside diameter of the blank shaped cross section is obtained by contouring of the mandrel and the roll
a process for hot or cold seamless shaping of dished part it uses the combined forces of rotating and pressure
drawing is the process of reducing the cross-sectional area and the shape of a rod, bar, tube or wire by pulling through a die
a sheet blank is forced by a punch into a die to form a deep recessed part this process is used to produce cylindrical cup shape
an internal pressure is applied so as to form a tube to the desired shape the internal pressure can be delivered by expanding a punch through a fluid
roll bending gives a curvature to a sheet, bar or shaped section by bending it between two or three cylindrical rolls
Cold stamping Tailor welded blank Roll forming Hot stamping
1. 다음사진의제품을제조하기위해어떤공정으로성형할지설명하시오. ( 각 5 점 ) (1) CNG (Compressed Natural Gas) 압력용기 (2) 풍력발전기타워플랜지 (3) 자동차알루미늄서스펜션암 (4) 금속재파이프
Selection of a Metal Forming Process? Preparation of Material? Tool Design? Machine or Equipment?
Billet material Tooling Interfacial condition Flow stress as a function of strain, strain rate, temperature, microstructure (constitutive equation) Workability as a function of strain, strain rate, etc (forming limit diagram) Surface condition Mechanical properties (thermal/physical) Geometry of tools Surface condition Heat treatment / hardness Accuracy / tolerances Lubricant type and condition Cooling characteristics of the interface layer Friction f,,t k 3 P mk