3.6 自由锻件的结构工艺性有哪些要求?自由锻件上为什么不允许出现凸台、肋 条和斜面? P139 考虑到自由锻设备和工艺的特点,自由锻件结构的设计原则是:在 满足使用性能的前提下,锻件的形状应尽量简单、规则,易于锻造。 1.避免锥体或斜面结构。 2.避免以空间曲面相交的结构。 3.避免加强肋和凸台等结构。 4.合理采用组合锻件。 锻造具有锥体或斜面结构的锻件,需制造专用工具,锻件成形也比较困难,从 而使工艺过程复杂,不便于操作,影响设备使用效率,应尽量避免。 如果出现凸 台、肋条,难以用自由锻成形,增加成本,若采用特殊工艺来生产,会降低生产 率,增加成本。 3.9 对于冲裁件、弯曲件和拉深件,在形状设计上有何特别要求? P141 P132 P143 冲裁件的形状应力求简单、对称,并尽可能采用圆形、矩形等规则形状,避免长槽和细长悬臂结构(图3(74),避免设计成非圆曲线的形状, businessreception; carmaintenance enterprise carsales after-salesservice integration enterprise business productionmanagement; Carmaintenance enterprise carsales after-salesservice integration enterprise technology management; carmaintenance enterprise carsales after-salesservice integration Enterprise car accessories management; carperformance detection Enterprise car performance detection detectionequipment maintenance; cartransport enterprise car using management; insurancecompany vehicles accident site exploration; carmanufacturing enterprise car performance detection getcertificate teachingplans according educationhigh vocational designed professional directory prepared Professionalcode:), socialsecurity all four car mechanic nationaloccupational standards occupational functions skillrequirements, students completing courseunder teachingplan, core double certificate course score up 60points mechanicaldrawing, engineering mechanics, mechanics, automotive materials processingtechnology, basic knowledge 废料最少。