複合式電鑄模具製程研究

Abstract

電鑄快速模具技術與其他快速模具技術相較有表面精度佳、模仁壽命長、可製作微細特徵等優點，其模仁之機械性質最接近傳統鋼模，是相當具有潛力的快速模具技術，然而電鑄快速模具技術因受到電鑄之物理限制，在製作具有高深寬比特徵之模仁時，其製作時間相當冗長，甚至無法製作，失去快速模具“快速”與“成本”之優勢。 因此本研究提出一種複合式電鑄模具之技術，將模仁結構拆解為NC加工部分與電鑄製作部份，模仁中不易電鑄製作之部分利用NC加工之方式做出其特徵後，置入已做導體化之電鑄母模孔穴中進行電鑄，在電鑄的過程中NC工件會逐漸與電鑄部分結合，形成高深寬比之模仁結構，此種製程結合NC與電鑄的優點，相較以往單純使用電鑄製造快速模具，大幅度降低了開模的時間與成本，且獲得優異的產品精度。 研究的結果證實，利用複合式電鑄模具技術可提供電鑄製模技術更大的應用彈性，增加其商業應用價值。

Rapid Tooling (RT) by using various back-up filler materials to reinforce the electroformed metallic thin shell resulted from rapid prototype has been proved feasible. However, electroforming on the prototype consisting high aspect ratio features is time consuming. Besides, it usually leads to distortion of the electroformed part. In this thesis an approach by integrating the Numerical Control (NC) machining with electroforming for RT purpose of the part having high aspect ratio features is proposed. Portions of the part that are difficult to be electroformed such as concaves, slots, vertical side walls, etc. are determined in advance based on the analysis of the CAD model. They are manufactured by CNC machining on the same electroformed material. They are inserted into the electroless plating RP model, and are jointed with each other during the following rotary-cathode electroforming process. Various parts having high aspect ratio features are taken to verify the proposed approach. It is found that the molds of acceptable accuracy are obtained. The NC part is closely joint with the electroformed shell. Analysis of the operations involve in mold making shows that the proposed approach can greatly shorten the time required in manufacturing the mold.