鉚接扣件多道次之冷鍛製程分析

An Analysis of the Multi-pass Cold Forging Process for Rivet Fastener

陳柏睿(Po-Jui Chen)

指導教授 ： 許源泉

國立虎尾科技大學/工程學院/機械與電腦輔助工程系碩士班在職專班/碩士(2012年)

https://doi.org/10.6827/NFU.2012.00127

摘要

台灣扣件產業舉世聞名，為台灣經濟發展帶來了甚多貢獻；多數的扣件製品以冷間鍛造方式製造生成，盤元線材經打頭機施以鍛粗及擠伸加工後產出一顆顆精良的扣件成品，然而精湛技術的背後確是業者長期辛勤投入所累積換取而來。目前業界所面臨最大的問題乃製程技術及模具設計大多仍仰賴過往經驗準則及反覆試誤法方式進行，不僅無法降低開發試誤成本、且費工耗時，更易造成因人為關係導致技術經驗流失的窘境；有鑑於此本研究希望能透過CAE電腦輔助模擬分析技術的應用及實物試驗，讓加工製程能藉由以理論基礎根據的方式研究觀察及探討，帶動整體扣件成形技術及品質的提升。

本文以鉚接扣件為研究題材，探討多道次冷間鍛造加工製程，以數值模擬分析及實物試驗兩部分來進行研究分析。文中數值模擬分析部分採用有限元素法DEFORM-3D軟體，模擬分析預測三道次成形過程中，各道次塑性加工行為之胚料流動變形、成形負荷、應力、應變分佈及模具應力、磨耗等現象。並將模擬分析結果與實物試驗部分比對驗證，觀察加工過程中各現象變化及對應關聯性或差異性；同時檢証所規劃之製程道次及模具設計是否具生產性。

從模擬所得結果觀察，胚料在三道次流動變形中以第一道次擠伸縮徑變化最為明顯，第二、三道次中鍛壓及沖孔兩作動有微小時間差。在成形負荷方面，依道次順序分別為10.09tons、6.12tons、10.44tons。則成形件最大等效應力，一道次位在縮徑變化處，二、三道次反應在頭端受壓處及尾端沖孔處。成形件最大等效應變，一道次發生在縮徑變化處，二、三道次發生在尾端沖孔尖錐斜面部。另模具最大等效應力，一道次產生成形沖頭前端，二、三道次產生在沖孔頂針底根部。整體三道次模具磨耗現象以第二道次為最大，磨耗位置落在成形沖頭上。尺寸比對上，最大誤差值為6.5%。

經由實物試驗與模擬分析結果比對顯示，本研究模擬分析數據與成形實物尺寸有其對應性，實際驗證模擬數據結果具有高度參考價值，將可做為後續投入扣件製程準備及模具開發設計時參考依據。參照本文模擬分析方式進行製程分析應可節省冷鍛鉚接扣件試誤成本與工時，進而達到更有經濟效率之生產方式。

關鍵字

扣件 ； 冷間鍛造 ； 多道次製程 ； 有限元素法 ； 鍛粗 ； 擠伸

並列摘要

Taiwan’s Fastener industry is eminent in the world and it has contributed significantly to the Taiwan economy. Most of the Fastener products are manufactured by cold forging technology. Each fine fastener items is manufactured through upsetting and extruding process etc. However, all these excellent technologies are base on a long term of accumulation of try and error merely. The mostly problem in the industry is that the die design is base on personal experience from try and error. And this way will be not only highly cost and losing of experience but also can’t reduce the development time and human error in the processing. In regard to these reasons, this study were focus on both the theory of CAE technology and practical application in order to bringing up technology and quality of the plastic working for fastener.

The subject of this research is the riveted fastener, using both the Numerical Simulation analysis and practical ways to study the process of Multi-channel Cold forging.Some simulations in this study were using DEFORM-3D software. There are three simulation steps in the forming process. And each simulation included parameters that deformed of material, load, stress, strain distribution and die stress, wearing condition etc.This study found both the relationship and the different by comparing the result of simulation and practical. And verify if the die design and is process available for production.

According to simulation results, had shown that the most variation of extrude diameter shrink is in the first step. And there are slightly time different in the process of forge and punch between the 2nd and 3rd steps.The three steps of loads in forming are 10.09tons、6.12tons and10.44tons respectively.And the maximum stress distribution in the first step is occurred at diameter shrink area. The maximum stress distribution in the step 2nd and 3rd are front area and tail area respectively.The maximum strain distribution in the first step is occurred at diameter shrink area. The maximum strain distribution both the step 2nd and 3rd are the slant of sharp area in tail.And the maximum mold stress distribution in the first step is occurred at front area of puncher. The maximum mold stress distribution in the step 2nd and 3rd are bottom area of the thimble. The mostly wearing of mold is during the second channel which in the puncher. And the most deviation between simulation data and actual item is 6.5%.

According to the compare of dimensions between simulation and practical items that we can prove the analysis data of this study is meaningful. And this can be the reference for applying in process and die design development in the future.The analysis of this study can be further applying to create an economical production process that reducing the try and error time and cost for cold forging fastener.

並列關鍵字

Fastener ； cold forging ； multi-forging ； finite element method(FEM) ； upsetting ； extruding

參考文獻

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