成功设计一付深拉伸模的关键要点.docVIP

STAMPING Journal? Key design principles for successful deep drawing 成功深拉伸模的关键设计准则 By Art Hedrick, Contributing WriterMay 30, 2001 Successful deep drawing depends on many factors. Ignoring even one of them during die design and build can prove disastrous. 成功深拉伸模依赖很多因素. 在模具设计和制造中忽略其中任何一个因素都会导致灾难性的后果. Successful deep drawing depends on many factors. Ignoring even one of them during die design and build can prove disastrous. However, regardless of the many factors involved, the most important element to a successful deep drawing operation is initiating metal flow. The following are key elements affecting metal flow, and each of them should be considered when designing, building, or troubleshooting deep drawing stamping dies: 成功深拉伸模依赖很多因素. 在模具设计和制造中忽略其中任何一个因素都会导致灾难性的后果. 尽管在深拉伸工艺中有很多因素要考虑, 然而决定成功的最重要的因素源于金属的流动. 以下列出一些影响金属流动的关键因素, 这其中任何一种在深拉伸冲压模具的设计, 制造或者在故障诊断中都应当考虑. Material type 材料类型 Material thickness 材料厚度 N and R values N 和R 值 Blank size and shape 展开平板的尺寸和外形 Part geometry 零件的几何尺寸 Press speed (ram speed) 冲床速度 (压头速度) Draw radii 拉伸圆角 Draw ratio 拉伸率 Die surface finish 模具表面的光洁度 Die temperature 模具的温度 Lubricant 润滑 Draw bead height and shape 拉延阻筋的高度和形状 Binder pressure 压边圈的压力 Binder deflection 压边圈的变形 Standoff height 平衡垫片 (上下压边圈之间) 厚度 Because thicker materials are stiffer, they hold together better during deep drawing. Thicker materials also have more volume, so they can stretch longer distances. 由于较厚的材料刚性好, 因此在深拉伸时, 不易断裂. 又由于较厚的材料有更大的容积, 所以它们能拉延更长. The N value, also called the work hardening exponent, describes the ability of a steel to stretch. The R value—the plastic strain ratio—refers to the ability of a material to flow or draw. Blank sizes and shapes that are too large can restrict metal flow, and the geometry of parts affects the ability of metal to flow. Press speeds must allow time for materials to flow. N 值也叫冷作硬化指数, 它是描述钢材拉伸能力的指标. R值也叫塑性变形系数---用来度量材料的流动和拉伸能力的. 展开平板的尺寸和形状若太大都阻碍金属的流动, 以及完成品零件的几何外形也影响金属的流动能力. 冲床的速度应容许留出金属流动所需足够的时间. Die surface finishes and lubricants