精微錐杯成形與沖壓技術資料庫之建立

Abstract

國內關於傳統沖壓的資料相當豐富，但都過於散亂，缺乏整理歸納，且每本書所專精的部份其實不盡相同，因此在學習上較為困難，本研究將這些使用廣泛的傳統沖壓書籍整合成一個沖壓資料庫，同時建立一個方便的使用者介面。而精微沖壓成形是目前研發中的新科技，本研究是以傳統沖壓為基礎建構精微沖壓之架構，並以國外期刊為主要資料來源，以此作為研究精微沖壓成形之基礎。沖壓資料庫的儲存架構將以目前使用最廣泛的關聯式架構為主，並選用商用軟體Access、SQL sever、Visual Basic作為建構的工具，開發適用於一般公司的主從式系統架構。在本研究中，依功能屬性，主要將資料庫分為知識庫與製程專案兩大部份，知識庫其主要功用是讓使用者可以直接查詢與瀏覽關於沖壓模具的知識，而製程專案是搭配著知識庫來幫助使用者做設計模具與輸出儲存紀錄的工作。 本研究在資料整理與收集方面，目前已收集國內外相關的研究成果，並加以整理與歸納分析。同時針對無文獻可供參考的部份，如尺寸效應下材料成形機制與微摩潤機制，本研究開發出精微錐杯擠製技術，以探討精微材料的成形性與摩擦。 在探討尺寸效應下材料成形機制方面，本研究發現材料之成形性與晶粒大小及特徵尺寸的比例有關。在相同潤滑條件下，晶粒尺寸趨於錐杯杯部的兩倍壁厚時，薄壁已不易成形，而細晶粒則無此情況，表示結晶尺寸的大小會影響材料之流動，導致成形性之改變，此應是造成尺寸效應的主要機制之一。 在微摩潤機制之研究發現，當晶粒相對特徵尺寸較小時，液態潤滑摩擦因子會隨尺寸縮小而上升，固態潤滑影響雖然較小，但仍會些微提升，此說明在尺寸縮小的情況下，摩擦因子會逐步提升，使其難以掌握，但由結果仍可歸納出尺寸效應下之摩擦因子。本研究之成果，將來可作為後續精微成形製程研究之基礎。

Though the documentation of the stamping technology has been widely published, the corresponding database is not well established yet. Therefore, the development of stamping technology is pretty much relied on the experienced engineers in a traditional stamping plant at present time. In the present study, the published stamping technology was thoroughly surveyed and categorized systematically. A computer database was then established for the traditional stamping technology. The database is on a client/server structure established using Access and Visual Basic. The database structure is multi-layered and has the functions of knowledge database search and stamping die design. A user friendly interface was built for either function. In the knowledge database search, the desired stamping technology can be retrieved conveniently in a short time. The die engineer can also sketch the stamping die plan including the process design and die design following the instructions given in the established database. The established database could be used as stamping die design handbook and the design tool as well. In addition to the conventional stamping technology, the latest technology of micro-forming was also collected in the present study. Since the technology of micro-forming is still under developing, the published technology is very limited. In order to study the size effect on the formability and tribology in micro-forming, a conical cup extrusion experiment was designed and conducted in the present study. The deformation mechanism that causes size effect was investigated by experiments. It is found that the formability of the material is affected by both the dimension of the specimen and the grain size. The formation of the side wall in the conical cup extrusion process becomes more difficult when the grain size reaches two times of the wall thickness. However, if the grain size is much refined, this effect is not so significant. It implies that the grain size is a major parameter in the micro-forming process. The experimental results also reveal that the value of friction factor (m) becomes larger as the grain size decreases for the liquid lubricant being used. However, the size effect on the tribology is not so significant if the solid lubricant is adopted.