电铸

电铸是一种通过electrodeposition在一个模具上制造金属成形零件的过程，在业内被称为mandrel。 导电（金属）模具被处理以创建一个机械分离层，或者通过化学钝化来限制电形粘附到模具上，从而允许其后续分离。 非导电（玻璃、硅、塑料）模具在电沉积之前需要沉积一层导电层。 这些层可以通过化学方式沉积，或使用真空沉积技术（例如，金溅射）。 模具的外表面形成形状的内表面。

该过程涉及将直流电通过含有被电成型金属盐的电解质。 阳极是被电铸的固体金属，而阴极是模具，电形被镀（沉积）到模具上。 该过程继续进行，直到达到所需的电形厚度。 然后，模具要么完整分离，要么融化，要么化学溶解。

完成零件的表面与模具紧密接触，从而精细复制了原始模具，并且不会像在铸造金属物体中那样经历收缩，也不会有铣削零件的工具痕迹。 零件的溶液侧边界开始时并不明确，并且随着沉积物厚度的增加，边界变得越来越模糊。 这种趋势可以通过屏蔽或一种称为周期性反转的过程来减少，在该过程中，电铸电流在短时间内反转，并且多余的部分通过电化学优先溶解。 完成的形态可以是成品零件，也可以用于后续过程以生产原始模具形状的正形，例如用于唱片或CD和DVD模具制造。

近年来，由于其几乎无损复制模具表面的能力，电铸在制造微型和纳米级金属设备以及生产具有微型和纳米级特征的精密注塑模具以生产非金属微型成型物体方面变得越来越重要。

电铸是一种 金属成形 零件制造过程，通过 electrodeposition 在一个模具上，在业内被称为 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状的内表面。

该过程涉及将直流电通过含有被电成型金属盐的电解质。  The anode is the solid metal being electroformed, and the cathode is the mandrel, onto which the electroform gets plated (deposited). 该过程继续进行，直到达到所需的电形厚度。然后，模具要么完整分离，要么融化，要么化学溶解。

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. 部件的溶液侧边界开始时并不明确，并且随着沉积物厚度的增加，边界变得越来越模糊。 This tendency can be reduced by shielding, or a process known as periodic reverse,Journal of Applied Electrochemistry 1979 407-410 Periodic reverse current electroplating and surface finishing. M.I. Ismail 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.

工艺流程
在基本电铸工艺中，电解槽用于将镍或其他可电铸金属沉积到模型（芯轴）的导电表面上。一旦沉积的材料达到所需的厚度后，可将电铸件从基体上分离。 
该工艺可精确复制芯棒的表面纹理和几何形状，单位成本低，可重复性高，工艺控制出色。

如果心轴是由非导电材料制成，则可以在其表面涂上一层薄薄的导电层。

 优点和缺点 

电铸的主要优点是它可以精确复制模具的外形。通常来说，精确加工一个腔体比加工一个凸形更具挑战性；然而，对于电铸来说，情况正好相反，因为模具的外部可以精确加工，然后用于电铸一个精密的腔体。

与其他基本的金属成形工艺（如铸造、锻造、冲压、深拉、机械加工和制造）相比，当要求极端公差、复杂性或轻量化时，电铸非常有效。光刻法生产的导电图案基材所固有的精度和分辨率，使得可以在保持优良边缘定义和接近光学光洁度的同时，生产出更精细的几何形状并达到更紧密的公差。电铸金属可以非常纯净，其精细的晶体结构使其性能优于锻造金属。多层电铸金属可以相互结合或与不同的基材材料结合，生产出带有“生长”法兰和凸台的复杂结构。

有报道指出，电铸的公差可达到1.5到3纳米。

电铸可以制造各种形状和尺寸，主要限制是需要将产品从模具上分开。由于产品的制造只需要一个模型或芯轴，因此可以经济地进行小批量生产。

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.

电成型可以制成各种形状和尺寸，主要限制是需要将产品从模具上分开。 由于产品的制造只需要一个模型或芯轴，因此可以经济地进行小批量生产。

参见
LIGA
Electrotyping
电镀
 电化学工程

参考文献

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

外部链接



Category:Metal forming
Category:Metallurgical processes