Work Hardening Distribution and Iron Loss of Electrical Steel after Punching Process

電磁鋼片在製程中會因產生殘留應力及塑性變形等因素造成電磁特性之惡化，進而對電動機之效率產生不良之影響。這些製程上的影響是電動機整體效率與預期上有所落差的原因之一，且各製程上可能產生之損耗是非常複雜且難以預估的，因此本實驗針對沖壓製程進行探討，了解其如何造成電磁鋼片之損耗。 在本實驗中，分別探討沖壓槽型、沖壓參數及沖壓斷面對電磁鋼片特性之影響，其中包括三種槽型、十組參數，並依硬化分布及估算之鐵損作為評估對電磁特性影響之依據。 在槽型實驗中，以改變槽型之倒角半徑進行，上倒角半徑設計有0.254mm、1mm、2mm，下倒角半徑則有尖角、0.254mm、0.4mm等設計，實驗結果顯示，增加倒角半徑能減少在倒角區之硬化影響區及鐵損，但倒角半徑過大時會使倒角區所佔比例增加，使整體鐵損上升，而最佳之槽型設計能改善鐵損約16%。 在沖壓參數實驗中，提高沖頭速度、沖壓行程模式為振動模式且較大之振幅、提高壓料板壓力及反壓板壓力皆能降低硬化影響區域及鐵損，而其中改善效果最佳之參數為沖壓行程，當振幅為80μm時，鐵損能降低30%。 在沖壓斷面品質之研究中，可發現在深度較深之區域其硬化程度有明顯的增加，並與沖壓斷面區域分布有關，而調整參數能影響各區域之分布。The iron loss of the electrical steel sheet increases dramatically due to the plastic strain and work hardening after punching process. This effect also reduces the overall efficiency of the motor, and the iron loss effect of electrical steel sheet in the punching process is difficult to predict and control. So, in this research will discuss the iron loss in punching process. In order to find out the reason of the iron loss in punching process, this research will discuss the slot of stator, the parameter of punching process and the quality of cutting edge. To discuss the effect of punching process, work hardening distribution and estimated iron loss is used to be a standard of comparison. In the experiment of the slot of stator, three slots with different fillet radius was discussed. The fillet radius of upper part has 0.254mm, 1mm and 2mm. The fillet radius of bottom part has cusp angle, 0.254mm and 0.4mm. The results show that the hardening area and the iron loss in the fillet area will reduce when increasing the fillet radius. When the fillet radius exceeds 1mm, the iron loss will increase due to the fillet area increase. The best design of slot can reduce 16% of iron loss. In the experiment of the parameter of punching process, the hardening area and the iron loss can be reduced by raising the punching speed, punching with vibration mode and large amplitude or raising blank holder and counter punch pressure. In these four parameters, adjusting punching mode makes biggest effect on reducing iron loss. When using vibration mode and amplitude 80μm can reduce 30% of iron loss. In part of the quality of cutting edge, the work hardening will be severe when measuring in deeper depth, and relates to the part of cutting edge. Adjusting the parameter of punching process can change the distribution of cutting edge