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Milling Cutters and Associated Technologies Part 3

Tham khảo tài liệu 'milling cutters and associated technologies part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Milling Cutters and Associated Technologies 169 Insert wear uneven - possibly resulting from inadequate pre-setting of the cutting inserts - allowing some to stand-proud of the rest and as a consequence being subjected to higher wear than the others Insert shape irregularities - possibly the result of poorly manufactured cutting insert geometries creating differing heights once secured and accurately positioned in their respective milling insert seatings Irregular chip-flow - possibly the result of either the insert chip-breakers operating inconsistently or the workpiece material having matrix inconsistencies. 4.2 Pocketing Closed-Angle Faces Thin-Walled and Thin-Based Milling Strategies Pocket Milling In particular and in the aerospace industries aluminium machining from wrought extruded stock and forged parts is a regular practice and to a lesser extent this also occurs in many precision machining environments. Often both for shallow and deep pockets and for ribs it is necessary to relieve weight at critical sections on components. One of the oldest established techniques for achieving pocket features is to drill a hole at the centre of the pocket to a pre-set depth. Then change tools and placing the milling cutter in this hole clear-out the pocket repeating this cycle until the pocket is roughed-out . Perhaps changing cutters and taking finishing cuts to complete the feature Fig. 87ai . Rather than simply plunging to depth with the cutter ramping-down into pockets is an effective way of reaching the first-level for the pocket s area clearance. Both ramping and double-ramping i.e. this latter technique is particularly efficient for smaller pocket dimensions are ways of removing stock via a diagonal plunge while taking the milling cutter to its required depth Fig. 87aii . This technique is an efficient machining strategy for the milling of square and rectangular pockets - for high stock removal. If the pocket is of non-uniform dimensions then perhaps a lace or .