小喵酱碎碎念
‘undercut’是一个单词。在焊接上称为‘咬边’，在伐木方面这个词系指砍树时现在树的根部侧面砍出一个契口，以便从树的另一边将树推倒，与此相同的词有：kerf、dip等。根据这几个词的汇总理解，在你的模具我方面建议译为侧边凹槽/侧凹槽。不一定合适，请参考。
阿里嘎多~
Since the cut blank will be retained in the die block by friction , some means of ejecting on the ram upstroke must be provided . 由于摩擦会导致切下的毛坯残留在模块里，所以必须在顶出时提供一个向上的冲力。A knockout assembly consists of a plate , a push rod , and a retaining collar . 顶出的安装部件包括一个金属板，推杆，定位圈。The plate is a loose fit with the die opening contour, and moves upward as the blank is cut . 该板与开模线是宽松式的，并且在毛坯切割时向上移动。Attached to the plate , usually by rivets , is a heavy push rod which slides in a hole in the shank of the die set .通常，利用铆钉将模柄孔中滑动的推杆安装在金属板上。 This rod projects above the shank, and a collar retains and limits the stroke of the assembly. 人们将该推杆设计在模柄上，并安装了定位圈，来减少安装带来的冲击力。Near the upper limit of the ram stroke, a knockout bar in the press will contact the push rod and eject the blank .接近限制冲力最高点时，压力推动下的脱模杆会与推杆接触并将毛坯顶出。 It is essential that the means of retaining the knockout assembly be secure, since serious damage would otherwise occur. 保证脱模安装的安全性是十分重要的，否则一些严重的危害就会发生。 In the ejection of parts , positive knockouts offer the following advantages over spring strippers where the part shape and the die selections allow their use: 在零件顶出过程中，正确的顶出方式比弹簧脱模机的效果要好，因为零件外形和模具部件会对脱模机有要求。 1. Automatic part disposal. The blank, ejected near the top of the ram stroke can be blown to the back of the press, or the press may be inclined and the same result obtained. 自动销毁零件。顶出接近冲力最高点时，毛坯会被冲到压力后方，或者压力可能倾斜，并达到同样的效果。 2. Lower die cost. Knockouts are generally of lower cost than spring strippers. 较低的模具消耗。总体来说，顶出要比弹簧脱模机成本少。 3. Positive action. Knockouts do not stick as spring strippers occasionally do. 正确的方式。弹簧脱模机通常会有粘合现象，顶出则不会。 4. Lower pressure requirements. There are no heavy springs to be compressed during the ram descent.较低的压力要求。没有任何重型弹簧能够承受冲击时的压力。完全是人脑翻译。本人接触模具行业一个月，如有不足请多包涵。希望对你有帮助。O(∩_∩)O
