Technology

Electroforming - Galvanoplasty

Electroforming has been a well-known and widely used procedure for many decades. Its principle is the electroforming of geometric shapes through the electrochemical deposition of a metallic coat onto a mould.

The mould is usually removable (through separation, smelting or etching), resulting in precise electroformed products or hollow parts that would be difficult to produce by traditional machining methods.

The term "galvanoplasty" refers to the original application of the procedure in fine art. Large statues and sculptures continue to be made by the deposition of copper coats onto a mould.

The applications of electroforming can be found in many fields:

• mechanical engineering (tools and moulds, gauges, coolers, exchangers, renovation of machine parts, electrodes, grinding tools with metal dies),
• electrical engineering (microwave components – waveguides, special conductive structures, coolers, tube parts, sponge electrodes for electrochemical cells),
• physics (mirrors, radiation deflectors, shielding elements),
• music industry (tools for compact disc and vinyl pressing),
• rubber industry (moulds for shoe sole pressing and the manufacture of imitations of natural materials),
• transport (headlamp reflectors, moulds for dashboard and gear stick pressing, rocket engine combustion chambers),
• glassmaking (moulds, grinding tools with metal dies).

Electroforming can be used to produce single or multiple casts of the mould with high precision (the deviation being only +/- 2.5 μm).

The final products can be composed of a combination of different metals to achieve a desired surface hardness (i.e., abrasion resistance, easy burnishing) and thermal conductivity (surface and body).

Electroforming can be used to create even very complicated shapes without having to prepare digital data. Thus, electroforming transcends the limitations of existing tooling processes such as the complicated milling of fine or deep reliefs (however, certain limitations apply when it comes to the electroerosion machining of very precise parts).

Moulds can be made of various materials such as:

• Plastics (ABS, Perspex…),
• Metals (duralumin, stainless steel, copper, low melt alloys),
• Moulding materials (waxes, silicones),
• Acrylate polymers, pure and metal-reinforced resins, PCM-enhanced gypsum.

Electroforming can also be used in cold welding, suitable for connecting metal parts without thermal diffusion between them – for example, connecting waveguide pipes to flanges (without gluing or soldering) or the manufacture of special metal-in-metal electrodes.

In a suitable design, chaplets, vents, ejector pins and runners can be attached to new electroformed moulds.