Fig. 2 Hole making by (a) punching, (b) punching and expansion, and (c) piercing. Source: Ref 1 More

Fig. 11 Center punching base material through a template More

Fig. 1 Shearing deformation during hole punching (a); initial indentation by the punch is followed by intense shearing between the punch and die and then fracture for final separation. These stages are manifest in the appearance and surface finish of the hole (b). Source: Ref 1 More

Fig. 3 Hole punching parameters. (a) Allowable sheet thickness-to-punch diameter for hole punching as a function of material shear strength. (b) Minimum punch diameter (hole size) as a function of material thickness for three materials: A, 195 MPa (28 ksi) copper; B, 345 MPa (50 ksi) steel; C More

Fig. 4 Edge distortion and cambering caused by hole punching near an edge or in an off-center row. Source: Ref 1 More

Fig. 10 Galling on surface of punch after punching each of ten holes More

Fig. 13 Punching-force calculations More

Fig. 17 Effect of punch-face shear on punching force More

Fig. 18 Effect of clearance on force required for punching with sheared tooling. Force F varies with cutting length L ; L depends on clearance and on the type and hardness of material. More

Fig. 24 Distortion resulting from off-center punching More

Fig. 25 Key for interpreting plot of loads from punching tests More

Fig. 8 Parts with holes punched by P/M tool steels. Parts include: punching of fine slots in brass parts for clocks; punching of 3 mm (0.118 in.) holes in high-carbon steel (0.7% C) sheet (240 HB); punching of holes in chain links made of 0.55% carbon steel with a thickness of 2 mm (0.079 More

Fig. 3 Hydraulic iron worker with 590 kN (66 tonf) punching capacity More

Fig. 23 A 160 kN (18 tonf) shear mounted at 45° angle for use with gang punching machine More

Fig. 11 Center punching base material through a template More

Fig. 5 Extensive cracking and punching shear damage to a bridge deck More

Fig. 6 Backward extrusion punch. A, nose angle; B, punch land; C, corner radius; D, relief angle More

Fig. 23 Guided punch. Courtesy of Durable Punch and Die Company More

Fig. 58 Three types of failure in deep drawing. (a) Fracture over punch nose; punch nose radius is too sharp. (b) Chevron fracture in wall; die-profile radius is too sharp. (c) Vertical crack in thick-walled cups; die-profile radius may be too sharp, and blank edge may be poor. More

Fig. 8 Punch force trajectories for samples 6 to 10 without process control. Punch force trajectories using constant binder force of 575 kN (65 tonf) More