As the engineering community and general public start to pay more attention to additive manufacturing, it's worth going beyond the excitement generated by 3D printing to look at alternative additive processes. One of these is electroforming, a process of electrodeposition that results in the particle-by-particle creation of parts on the micron and submicron scale.
OEMs are turning to electroforming when it's impossible for their processes to fabricate intricate parts at a very small scale. Nickel is the most popular choice of material for electroformed parts due to its favorable mechanical properties that make it well-suited to many applications.
"Nickel is the most popular choice of material for electroforming."
How Electroforming Works
Similar to the process used in photo etching, a film master called a phototool is created from CAD data. The phototool may contain dozens to thousands of images of the parts to be electroformed. A sheet of conductive metal, often stainless steel, is coated in photo resist and the phototool is used to expose the resist in the pattern of the parts. This master pattern, known as a mandrel, is imaged and developed, leaving bare metal in the outlines of the parts to be made. Multiple layers of resist can be used to achieve the desired thickness of the final parts.
Electroforming takes place in a conductive electrolyte bath that contains a metal salts solution - typically nickel sulfamate. The anode is a basket of solid nickel nuggets submerged in the solution and subjected to an electrical charge that drives positively charged ions into the electrolyte bath. The negatively charged cathode is the metal mandrel, mounted on a conductive rack and connected to a DC power supply at multiple points. Once the electrical current is applied, the nickel ions in solution migrate to the cathode and adhere to it as solid nickel atoms. The electrodeposition process continues as long as the electrical current is on.
Why Nickel Is The Most Common Metal In Electroforming
While copper, gold and other "noble" metals can be electroformed, nickel is the most versatile in this process. Nickel sulphamate and Watts solutions are the most commonly used electrolytic baths.
These nickel-based solutions give operators the opportunity to affect several material characteristics of the finished product. The hardness, ductility, strength and internal stress of the finished part can be varied by changing the makeup of the electrolytic solution. The solution can be altered through codeposition - alloying the nickel with another metal. This increases hardness while keeping internal stress low.
Nickel-cobalt alloys with 10–15 percent cobalt are common in electroforming. This alloy is useful because it has internal stress low enough for the electroforming process while enabling the creation of an alloy-enhanced finished part.
The versatility of nickel component parts has earned them a place in the manufacture of products in many industries, from the nickel-electroformed sieves, meshes and screens used in medical products to the ligatures and actuators in microelectronics. Aspect ratios up to 10:1 allow the creation of features that are taller than they are wide. This ability has growing opportunities as semiconductor chips grow more densely packed, driving a need for smaller leads and gaps.
For more information about electroforming capabilities, please download our free introductory guide:
If you're an engineer or designer at an OEM who is looking for a consistent process to create flat precision metal parts, call us at 800-443-5218 or email us at email@example.com and let's get started on your designs.