Dividing M ethods of forming and cutting technology .1 Summary

2.1.3 Dividing

Dividing is t h e first su bgro u p u n d er t h e h ead in g o f p art in g, bu t is gen - erally cat ego rized as a “fo rm in g t ech n iq u e” sin ce it is o ft en u sed wit h o t h er co m p lem en t ary p ro d u ct io n p ro cesses cf. Fig. 2.1.2 . Acco rd in g t o t h e d efin it io n o f t h e t erm , d ivid in g is t aken t o m ean t h e m ech an i- cal sep arat io n o f wo rkp ieces wit h o u t t h e creat io n o f ch ip s n o n -cu t - t in g. Acco rd in g t o DIN 8588, t h e d ivid in g cat ego ry in clu d es t h e su b- cat ego ries sh ear cu t t in g, wed ge-act io n cu t t in g, t earin g an d breakin g Fig. 2.1.28 . O f t h ese, t h e sh ear cu t t in g is t h e m o st im p o rt an t in in d u s- t rial ap p licat io n . 19 M ethods of forming and cutting technology punch w orkpiece blank holder Fig. 2.1.26 Displacement ϕ w orkpiece M T M T Fig. 2.1.27 Tw isting Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998 Shear cutting – kn o wn in p ract ice as sh earin g fo r sh o rt – is t h e sep ara- t io n o f wo rkp ieces bet ween t wo cu t t in g ed ges m o vin g p ast each o t h er Fig. 2.1.29 an d cf. Sect . 4.5 . Du rin g sin gle-stroke sh earin g, th e m aterial sep aration is p erform ed alon g th e sh earin g lin e in a sin gle stroke, in m u ch th e sam e way as u sin g a com p ou n d cu ttin g tool. Nibblin g, in con trast, is a p rogressive, m u lti- p le-stroke cu ttin g p rocess u sin g a cu ttin g p u n ch d u rin g wh ich sm all waste p ieces are sep arated from th e workp iece alon g th e cu ttin g lin e. Fine blanking is a sin gle-st ro ke sh earin g m et h o d t h at u ses an an n u lar serrat ed blan k h o ld er an d a co u n t erp ressu re p ad . Th u s t h e gen erat ed blan ked su rface is free o f an y in cip ien t bu rrs o r flaws, wh ich is fre- q u en t ly u sed as a fu n ct io n al su rface Fig. 2.1.30 an d cf. Sect . 4.7 . 20 Basic principles of metal forming parting dividing breaking tearing w edge-action cutting shear cutting Fig. 2.1.28 Parting techniques classified under forming open shearing blanking contour punch die Fig. 2.1.29 Shearing Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998 W edge-action cutting o f wo rkp ieces is gen erally p erfo rm ed u sin g a wed ge-sh ap ed cu t t in g ed ge. Th e wo rkp iece is d ivid ed bet ween t h e blad e an d a su p p o rt in g su rface. Bit e cu t t in g is a m et h o d u sed t o d ivid e a wo rkp iece u sin g t wo wed ge-sh ap ed blad es m o vin g t o ward s each o t h er. Th is cu t t in g m et h o d is em p lo yed by cu t t in g n ip p ers o r bo lt cu t t ers Fig. 2.1.31 . Th e p ro cesses tearing an d breaking su bject t h e wo rkp iece eit h er t o t en - sile st ress o r ben d in g o r ro t ary st ress beyo n d it s u lt im at e breakin g o r t en sile st ren gt h . 21 M ethods of forming and cutting technology die counterpunch punch serrated ring annular serrated blank holder Fig. 2.1.30 Fine blanking w orkpiece tool Fig. 2.1.31 Bite cutting Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998

2.1.4 Combinations of processes in manufacturing