What is the context? Electroforming applications often involve the fabrication of complex 3D shapes like moulds (e.g. for lenses, dashboards) and dies (e.g. for steel sheet shaping), leading edge rotors for helicopter blades, reflectors, etc. A non-typical example is the gold electroforming process for producing jewelry.

What are the issues?

Typically for Ni electro-forming applications, variations in the plated layer thickness are above a factor 2 for simple 3D mandrels, up to a factor 5 and more for complex 3D shapes, even at low applied current density values. In the high current density areas on the mandrel surface, there is risk for nodular or even dendrite growth, often forcing to interrupt the process several times in order to remove the excessive material by grinding.
2D electroforming applications often have very tight specifications on the layer thickness (e.g. 100 micron +/- 5 micron), making the engineering of the electroforming process challenging. Due to the fact that the substrate is often patterned (i.e. partly photo-resist covered, partly exposed), the layer thickness distribution will tend to be non-uniform not only on the macro-scale, but also on meso-scale level (i.e. from one device to another one) and on mini-scale level (within the dimension of individual devices).
Control of the current density distribution and layer thickness over the substrate to be electroformed can only be achieved with a thoroughly engineered tooling set, incorporating for example:

• pattern layout;
• current robbers either on the substrate (= ‘on-board’) or in front of the substrate;
• auxiliary or conforming anodes (fed by a an individual rectifier);
• insulating shields (screens).

What value do we bring?

An advanced control of current density and metal thickness distribution over a mandrel (3D) or substrate (2D) requires an intelligent engineering approach. Elsyca has a longstanding track record of selecting the best combination of tooling components from the categories as listed above to enable electroforming a mandrel or substrate within specifications.
Elsyca’s Advanced Engineering Services team uses its in house 3D software simulation platform to optimize the shape and position of the selected tooling components. This Computer Aided Engineering (CAE) work is performed while respecting all possible restrictions of the electroforming installation (e.g. the number of separate rectifiers available, each with their own nominal current value), practical restrictions for manufacturability, cost of the tooling and maintenance afterwards.