《零件的结构工艺性》PPT课件

Manufacturing Process Considerations 零件的结构工艺性,Casting structure 铸件结构 Common machining structures 机加工常见结构 Structure of drill hole 钻孔结构,请点击相应标题显示其内容,Casting structure 铸件结构,Sand box cover Overflow Pouring head 上砂箱 冒口 浇口,1. Draft 起模斜度:,The 120（3）draft along the drawing direction of the pattern facilitates to take out the pattern while molding. 铸件造型时，为便于取出木模，沿脱模方向的表面做出120（3）的起模斜度。,请点击鼠标左键显示后面内容,If the draft is very small, it can be omitted, If necessary, it can be included in technical.起模斜度较小时, 在图中一般不画出, 必要时可注写在技术要求中。,Sand box 下砂箱,Model 模型,Cavity 型腔,Sand 型砂,2. Fillets in castings 铸造圆角:,There must be a radius where two surfaces meet, in order to avoid sand drops while removing the mould and shrinkage cavity and shrinkage crack while cooling. 在铸件表面相交处应有圆角,以免 脱模时砂型落砂,同时防止铸件冷却时产生裂纹或缩孔。,Machine symbol 机加工符号,请点击鼠标左键显示后面内容,Casting structure 铸件结构,The intersection line is needed in order to distinguish the various surfaces. The one we have provided is called run-out line. The representation of a transition line is similar to that of intersection line. The only difference is that the end of the run-out line is not connected with the contour line of the radius, and the line style is a thin solid line. 为了区分不同形体的表面,仍要画出相贯线,这种相贯线称为过渡线。过渡线的画法和相贯线相同,只是其端点处不与圆角轮廓线接触,且线型为细实线。,3. Wall thickness 铸件的壁厚:,To avoid shrinkage cavity and shrinkage crack caused by different cooling speeds. During the design phase, it is a must to maintain uniform wall thickness or a smooth. One must avoid unequal designs such as thickness abrupt varying or local thick partial areas. 为防止浇铸零件 时,由于壁厚不匀而冷却速度不同产生的缩孔和裂纹, 在设计铸件 时, 应使壁厚尽量均匀或逐渐过渡, 以避免壁厚突变或局部肥大的 不匀现象。,请点击鼠标左键显示后面内容,Smooth transition 平滑过渡,Casting structure 铸件结构,Maintain uniform wall thickness 壁厚均匀,1. Boss club and recessed surface 凸台与凹坑：,Usually, all surfaces mounted on other parts need to be machined. The boss or recessed surface is added to keep good contact between the surfaces of two parts and to reduce the machining area and manufacturing cost. 零件上凡与其他零件接触的表面一般都要加工，为了保证两零件表面的良好接触，同时减少加工面积，以降低制造费用，在零件的需接触表面处常设计成凸台、凹坑的形式。,请点击鼠标左键显示后面内容,Common machining structures 机加工常见结构,2. Chamfer and round 倒角与圆角:,To eliminate burrs and flashes in order to prevent human hands from cutting and to facilitate mounting, the ends of both the shaft and the hole usually need to be chamfered.为了去除零件的毛刺、锐边，以防止划伤人手和便于装配，在轴和孔的端部通常需加工出倒角。,Avoid cracks避免断裂,That is, the sharp edge of shaft end is cut by a conical cutting tool with a 45 degree apex angle. 即用一锥顶角为45的圆锥刀头切除其端部锐边。,请点击鼠标左键显示后面内容,Common machining structures 机加工常见结构,An arc transition usually remains at the shaft shoulder, which is called round, in order to avoid cracks caused by pressure concentration. 在轴肩处，常常制成圆弧过渡，即圆角，以避免因应力集中而产生裂纹。,Common machining structures 机加工常见结构,Undercut 退刀槽,Undercut 退刀槽,Grinding undercut 砂轮越程槽,Grinding undercut 砂轮越程槽,Grinding surface 精磨表面,Grinding surface 精磨表面,3. Escape and grinding undercut 螺纹退刀槽和砂轮越程槽:,An escape, grinding or traveling limit undercut needs to be produced at the end of the surface to be machined, in order to easily withdraw the cutter or grinding wheel while tapping or grinding external diameter. 在车削螺纹或磨外圆时,为便于退刀 或使用砂轮, 需要在待加工面末端先切出退刀槽或砂轮越程槽。,请点击鼠标左键显示后面内容,The dimension of the escape is identified as widthdepth or widthdiameter. 退刀槽及越程槽的尺寸注成“宽度深度” 或“宽度直径”。,The axis of the drill should be perpendicular to the surface to be drilled, in order to ensure correct drilling position and prevent the drill from breaking caused by unequal impact force. 用钻头钻孔时，为保证钻孔位置准确和避免钻头因受力不均而折断，应使钻头轴线垂直于被钻孔零件的表面。,请点击鼠标左键显示后面内容,Structure of drill hole 钻孔结构,The intersection point where the hole and the oblique plane meet is necessary to set to platform and notch structure. If the angle between the drill and the oblique plane is larger than 60, one can drill the hole directly. 在与孔轴线倾斜的表面处,常需设计出平台或凹坑结构,但当钻头与倾斜面的夹角大于60时,也可以直接钻孔。,本 小 节 结 束,谢谢您的认真学习！,退出,前一页,Casting structure 铸件结构,不与轮廓线接触,在图片上点击鼠标左键 “暂停”或再次“播放”,Casting structure 铸件结构,在切点附近断开,在图片上点击鼠标左键 “暂停”或再次“播放”,Casting structure 铸件结构,在图片上点击鼠标左键 “暂停”或再次“播放”,Casting structure 铸件结构,在图片上点击鼠标左键 “暂停”或再次“播放”,Common machining structures 机加工常见结构,请 点 击 鼠 标 左 键 显 示 后 面 内 容,Grinding surface by grinding wheel 砂轮正在精磨工件的表面,Common machining structures 机加工常见结构,Structure of drill hole 钻孔结构,Surface structure of the drill hole 钻孔的表面结构,Representation of the hole and dimension of a drill 钻孔的尺寸标注,Grinding external diameter by grinding wheel 砂轮正在精磨斜齿轴的外圆面,Grinding undercut 砂轮越程槽,Common machining structures 机加工常见结构,在图片上点击鼠标左键可以“暂停”或再次“播放”,在图片上点击鼠标左键可以“暂停”或再次“播放”,在图片上点击鼠标左键可以“暂停”或再次“播放”,在 图 片 上 点 击 鼠 标 左 键 可 以 “暂 停” 或 再 次 “播 放”,