電鑄

Electroforming process

電鑄是一種通過electrodeposition在一個模具上製造金屬成形零件的過程，在業內被稱為mandrel。 導電（金屬）模具被處理以創建一個機械分離層，或者通過化學鈍化來限制電形粘附到模具上，從而允許其後續分離。 非導電（玻璃、矽、塑料）模具在電沉積之前需要沉積一層導電層。 這些層可以通過化學方式沉積，或使用真空沉積技術（例如，金濺射）。 模具的外表面形成形狀的內表面。

該過程涉及將直流電通過含有被電成型金屬鹽的電解質。 陽極是被電鑄的固體金屬，而陰極是模具，電形被鍍（沉積）到模具上。 該過程繼續進行，直到達到所需的電形厚度。 然後，模具要麼完整分離，要麼融化，要麼化學溶解。

完成零件的表面與模具緊密接觸，從而精細複製了原始模具，並且不會像在鑄造金屬物體中那樣經歷收縮，也不會有銑削零件的工具痕跡。 零件的溶液側邊界開始時並不明確，並且隨着沉積物厚度的增加，邊界變得越來越模糊。 這種趨勢可以通過屏蔽或一種稱為周期性反轉的過程來減少，在該過程中，電鑄電流在短時間內反轉，並且多餘的部分通過電化學優先溶解。 完成的形態可以是成品零件，也可以用於後續過程以生產原始模具形狀的正形，例如用於唱片或CD和DVD模具製造。

近年來，由於其幾乎無損複製模具表面的能力，電鑄在製造微型和納米級金屬設備以及生產具有微型和納米級特徵的精密注塑模具以生產非金屬微型成型物體方面變得越來越重要。

電鑄是一種 金屬成形 零件製造過程，通過 electrodeposition 在一個模具上，在業內被稱為 mandrel. Conductive (metallic) mandrels are treated to create a mechanical parting layer, or are chemically passivated to limit electroform adhesion to the mandrel and thereby allow its subsequent separation. Non-conductive (glass, silicon, plastic) mandrels require the deposition of a conductive layer prior to electrodeposition. Such layers can be deposited chemically, or using vacuum deposition techniques (e.g., gold sputtering). 模具的外表面形成形狀的內表面。

該過程涉及將直流電通過含有被電成型金屬鹽的電解質。 The anode is the solid metal being electroformed, and the cathode is the mandrel, onto which the electroform gets plated (deposited). 該過程繼續進行，直到達到所需的電形厚度。然後，模具要麼完整分離，要麼融化，要麼化學溶解。

The surface of the finished part that was in intimate contact with the mandrel is replicated in fine detail with respect to the original, and is not subject to the shrinkage that would normally be experienced in a foundry-cast metal object, or the tool marks of a milled part. 部件的溶液側邊界開始時並不明確，並且隨着沉積物厚度的增加，邊界變得越來越模糊。 This tendency can be reduced by shielding, or a process known as periodic reverse, where the electroforming current is reversed for short periods and the excess is preferentially dissolved electrochemically. The finished form can either be the finished part, or can be used in a subsequent process to produce a positive of the original mandrel shape, such as with vinyl records or CD and DVD stamper manufacture.

In recent years, due to its ability to replicate a mandrel surface with practically no loss of fidelity, electroforming has taken on new importance in the fabrication of micro- and nano-scale metallic devices and in producing precision injection molds with micro- and nano-scale features for production of non-metallic micro-molded objects.

工藝流程

電鑄工藝詳情

在基本電鑄工藝中，電解槽用於將鎳或其他可電鑄金屬沉積到模型（芯軸）的導電錶面上。一旦沉積的材料達到所需的厚度後，可將電鑄件從基體上分離。 該工藝可精確複製芯棒的表面紋理和幾何形狀，單位成本低，可重複性高，工藝控制出色。

如果心軸是由非導電材料製成，則可以在其表面塗上一層薄薄的導電層。

優點和缺點

電鑄的主要優點是它可以精確複製模具的外形。通常來說，精確加工一個腔體比加工一個凸形更具挑戰性；然而，對於電鑄來說，情況正好相反，因為模具的外部可以精確加工，然後用於電鑄一個精密的腔體。

與其他基本的金屬成形工藝（如鑄造、鍛造、衝壓、深拉、機械加工和製造）相比，當要求極端公差、複雜性或輕量化時，電鑄非常有效。光刻法生產的導電圖案基材所固有的精度和解像度，使得可以在保持優良邊緣定義和接近光學光潔度的同時，生產出更精細的幾何形狀並達到更緊密的公差。電鑄金屬可以非常純淨，其精細的晶體結構使其性能優於鍛造金屬。多層電鑄金屬可以相互結合或與不同的基材材料結合，生產出帶有「生長」法蘭和凸台的複雜結構。

有報道指出，電鑄的公差可達到1.5到3納米。

電鑄可以製造各種形狀和尺寸，主要限制是需要將產品從模具上分開。由於產品的製造只需要一個模型或芯軸，因此可以經濟地進行小批量生產。

The main advantage of electroforming is that it accurately replicates the external shape of the mandrel. Generally, machining a cavity accurately is more challenging than machining a convex shape; however, the opposite holds true for electroforming because the mandrel's exterior can be accurately machined and then used to electroform a precision cavity.

Compared to other basic metal forming processes (casting, forging, stamping, deep drawing, machining, and fabricating), electroforming is very effective when requirements call for extreme tolerances, complexity, or light weight. The precision and resolution inherent in the photo-lithographically produced conductive patterned substrate allows finer geometries to be produced to tighter tolerances while maintaining superior edge definition with a near-optical finish. Electroformed metal can be extremely pure, with superior properties over wrought metal due to its refined crystal structure. Multiple layers of electroformed metals can be bonded together, or to different substrate materials, to produce complex structures with "grown-on" flanges and bosses.

Tolerances of 1.5 to 3 nanometers have been reported.

電成型可以製成各種形狀和尺寸，主要限制是需要將產品從模具上分開。 由於產品的製造只需要一個模型或芯軸，因此可以經濟地進行小批量生產。

參見

• LIGA
• Electrotyping
• 電鍍
• 電化學工程

外部閱讀

• Spiro, P. Electroforming: A comprehensive survey of theory, practice and commercial applications, London, 1971.

外部連結

• Opti-Forms, Inc. - Optical Coatings, Electroformed Reflectors, Cold Shields. Opti-Forms, Inc. [2015-08-28]. （原始內容存檔於2014-03-11）. 
• NiCoForm, Inc. Net-shape Electroforming. www.nicoform.com. [2020-05-24].