Hsia Shao-Yi, Shih Po-Yueh
Department of Mechanical and Automation Engineering, Kao-Yuan University, Kaohsiung 82151, Taiwan.
Chong Cheng Fastener Corporation, 69 Da-Shun Rd. Guan-Miau, Tainan 71844, Taiwan.
Materials (Basel). 2015 Sep 25;8(10):6640-6657. doi: 10.3390/ma8105328.
Cold forging has played a critical role in fasteners and has been widely used in automotive production, manufacturing, aviation and 3C (Computer, Communication, and Consumer electronics). Despite its extensive use in fastener forming and die design, operator experience and trial and error make it subjective and unreliable owing to the difficulty of controlling the development schedule. This study used finite element analysis to establish and simulate wear in automotive repair fastener manufacturing dies based on actual process conditions. The places on a die that wore most quickly were forecast, with the stress levels obtained being substituted into the Archard equation to calculate die wear. A 19.87% improvement in wear optimization occurred by applying the Taguchi quality method to the new design. Additionally, a comparison of actual manufacturing data to simulations revealed a nut forging size error within 2%, thereby demonstrating the accuracy of this theoretical analysis. Finally, SEM micrographs of the worn surfaces on the upper punch indicate that the primary wear mechanism on the cold forging die for long hex flange nuts was adhesive wear. The results can simplify the development schedule, reduce the number of trials and further enhance production quality and die life.
冷锻在紧固件生产中发挥了关键作用，并且已广泛应用于汽车制造、制造业、航空业和3C（计算机、通信和消费电子）领域。尽管冷锻在紧固件成型和模具设计中应用广泛，但由于难以控制开发进度，操作人员的经验以及反复试验使得这一过程主观且不可靠。本研究基于实际工艺条件，运用有限元分析方法对汽车维修紧固件制造模具的磨损情况进行了建模与模拟。预测了模具上磨损最快的部位，并将所得应力水平代入阿查德方程来计算模具磨损。通过将田口质量法应用于新设计，模具磨损优化提高了19.87%。此外，实际制造数据与模拟结果的对比表明，螺母锻造尺寸误差在2%以内，从而证明了该理论分析的准确性。最后，上模磨损表面的扫描电子显微镜照片表明，长六角法兰螺母冷锻模具的主要磨损机制是粘着磨损。研究结果能够简化开发进度，减少试验次数，并进一步提高生产质量和模具寿命。
