Electrical Contact Riveting Process

To reduce the high cost burden of mold manufacturing, a machining method using Wire Electrical Discharge Machining (WEDM) is applied to produce precision workpieces, followed by precision riveting to secure the contact. This process requires a professional understanding of mechanical mechanisms.

Precision Base Plate Machining Using Wire Cutting

In small-lot production and prototype development, designing and manufacturing dedicated press molds incur significant time and cost. To overcome this, wire cutting technology is used. WEDM enables conductive materials to be cut with micrometer-level precision, allowing extremely accurate control of the tolerance of the rivet insertion hole.

The success of the riveting process depends on the fit between the rivet diameter and the base-plate hole. Holes machined via wire cutting have uniformly smooth internal surfaces, which reduce stress concentration during riveting and help minimize electrical contact resistance.

Plastic Deformation and Fixation Mechanism in Electrical Contact Riveting

Riveting is a permanent fastening process in which the rivet shank is mechanically compressed to induce plastic deformation. In electrical contacts, securing electrical conductivity is just as important as mechanical fixation.

During the upsetting process, where the rear side of the rivet is pressed to expand its diameter, the rivet material plastically flows and completely fills the interior of the hole. The rear end of the rivet spreads into a mushroom-shaped form, creating strong fastening force that prevents loosening caused by vibration or thermal expansion.

Characteristics of Different Riveting Methods

The most widely applied riveting methods in electrical contact assembly are impact riveting and orbital riveting. Impact riveting uses a strong instantaneous force, resulting in fast cycle time but also introducing a risk of micro-cracks due to the high shock load applied to the material.

On the other hand, orbital riveting applies a gradually rotating pressure with a tool slightly tilted from the rivet center axis. This method maximizes material flow, enabling precise deformation with less force, while effectively suppressing internal void formation that can be detrimental to electrical characteristics.

Process Parameters and Quality Indicators in Electrical Contact Riveting

For reliable riveting quality, pressing force, pressing time, and protrusion height must be strictly controlled. If protrusion height is too short, clamping force becomes insufficient and contact resistance increases. If excessive, deformation becomes unstable, leading to poor appearance and reduced mechanical strength.

Post-riveting caulking quality is also directly linked to electrical reliability. Higher interface bonding between the contact and base plate lowers contact resistance and suppresses heat generation during current flow.

Table 1. Process Parameters and Technical Considerations

Table 2. Comparison of Riveting Methods

The combination of precision machining using wire cutting and advanced riveting process control is a key driving force in improving the quality of electrical contact components. Optimizing the deformation profile on the rear side of the rivet to simultaneously ensure mechanical fastening strength and electrical conductivity is essential for manufacturing high-value precision components.