曲軸把活塞桿受到的力發送給發動機曲軸并和曲軸一起把活塞桿的直線運動轉換為傳動軸的轉動健身運動，其每一個循環系統中承擔更替2次拉應力和壓內應力，承受力頻率很高。因為曲軸承擔較大的負載，并在運轉的疲憊負載下工作中，故曲軸不但對抗壓強度有較高的規定，并且對品質尺寸公差明確提出高的規定。

曲軸樣子繁雜，自由鍛時，其工型桿部易造成折疊式，尤其是工型底端高寬比超過5的曲軸更易造成折疊式。處理對策主要是操縱胚料容積和預、終鍛工字型位置橫截面積的比率，并壓擠成型。此外曲軸在削邊時非常容易形變，可以在設計方案終CNC精密零件膛時，選用規格賠償來處理，但這規定煅造溫度和生產節拍穩定，還需要確保削邊刀口品質。更強選用削邊和校準復合型模。近年來又發生脹斷曲軸新技術應用。

The connecting rod transmits the force on the piston to the crankshaft and together with the crankshaft transforms the reciprocating motion of the piston into the rotating motion of the crankshaft. In each cycle, the connecting rod bears two alternating tensile and compressive stresses, with a high frequency of stress. Because the connecting rod bears a large load and works under the rotating fatigue load, the connecting rod not only has a high demand for strength, but also for the quality tolerance.

The shape of the connecting rod is complex. When forging, the I-shaped part of the connecting rod is easy to fold, especially when the width height ratio of the I-shaped bottom is greater than 5. The solution is mainly to control the ratio of the volume of the blank to the cross-sectional area of the I-shaped part of the pre and final forging, and to extrude. In addition, the connecting rod is easy to deform when cutting, which can be solved by dimension compensation when designing the final forging die bore, but this requires constant forging temperature and production beat, and must guarantee the quality of cutting edge. It is better to use trimming and correction compound die. In recent years, new technology of expanding and breaking connecting rod has appeared.

以上是《汽車典型CNC精密零件工藝特性概述》的介紹，原文鏈接：http://www.jileichina.com/cncjmjjg/8609.html