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© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Manufacturing Processes Manufacturing Processes
Sheet Metal FormingSheet Metal Forming판재 성형판재 성형
Associate Professor Su-Jin Kim
School of Mechanical EngineeringGyeongsang National University
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Sheet metal forming ( 판재성형 )
• Sheet metal forming is a processes that shape a piece of sheet metal into the desired part through shearing( 전단 ) and deformation( 성형 ).
• It is also called pressworking, press forming, or stamping.
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Contents
1. [Shearing]2. [Forming]3. [Press Die]
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Cutting with Shearing ( 전단 )• Sheet metal is separated by applying shearing force
using punch and die.• Edge fracture & burr.
Punch
Sheet metal
Die
F
Clearance
Rollover
Burnish
Fracture
Burr
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Cutting with shear
1. Shearing - Separating material into two parts 2. Blanking - Removing material to use for parts 3. Punching - Removing material as scrap
Blanking
Scrap
Part
Punching
Part
Scrap
Shearing
Part2Part1
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Shearing
• Shearing cuts straight line to separate a piece of sheet metal into smaller parts.
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Blanking
• Desired part (gears, key) is removed from sheet metal.• Fine blanking, applying 3 separate forces, produces
smooth and flat edges with minimal burrs and tolerances.
Punch
Upper pressure pad
Sheet metal
DieLower pressure cushion
Stringer
BlankingFineblanking
http://ma.gnu.ac.kr/vod/forming/Stainless_Spoon.wmv Spoon
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Punching
Scrap(Hole, slot) is removed from sheet metal.•Piercing - cylindrical punch •Slotting - rectangular holes •Perforating - large number of holes •Notching - edge of sheet •Lancing - partial cut to be bent •Slitting - straight line •Parting - separating a part•Cutoff - separating a part
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Punch Force
• The punch force is product of shear strength of sheet metal and cross-sectional area being sheared.
• Punch force : F ≈ (0.7σu)tl σu = ultimate tensile strengtht = thicknessl = total length of the sheared edge
t
l
F
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Estimate the force required in punching a 25 mm diameter hole through a1.8 mm thick 5052-O aluminium sheet at room temperature. Ultimate tensile strength of it is 190 MPa.
SolutionF = (0.7 190 Mpa) (1.8 π 25 mm2) = 18.8 kN
Ex) Calulation of punch force
© 2011 Su-Jin Kim GNU© 2011 Su-Jin Kim GNU
Sheet-Metal FormingSheet-Metal FormingManufacturing ProcessesManufacturing Processes
Punch press machine
• Punch press
bending tool
http://www.youtube.com/watch?v=vdqqm0Hi7nc LVD
http://www.youtube.com/watch?v=DvONyl-ncMo AMADA