A standardized method for measuring the force required to join wire harnesses and sparkplugs

Area of Science:

• Engineering
• Ergonomics
• Materials Science

Background:

• Accurate measurement of sparkplug wire insertion forces is crucial for design and ergonomics.
• Existing methods may not adequately account for variations in components or insertion processes.

Purpose of the Study:

• To develop and validate a methodology for measuring axial insertion forces of sparkplug wires onto sparkplugs.
• To establish a baseline for understanding force contributions from individual wire components.
• To provide a foundation for optimizing sparkplug wire design and manufacturing.

Main Methods:

• Utilized a three-axis programmable mill for controlled wire insertion onto a force transducer-mounted sparkplug.
• Analyzed force-displacement curves to identify inflection points and slopes corresponding to mechanical events.
• Dissected sparkplug wires to isolate and quantify the force contribution of each component.
• Applied linear superposition to model total insertion force based on component contributions.

Main Results:

• Identified distinct mechanical events during wire insertion, correlating with force-displacement curve characteristics.
• Demonstrated that individual component forces can be summed to estimate total insertion force.
• Established a repeatable methodology for quantifying axial insertion forces, independent of worker variation.

Conclusions:

• The developed methodology provides an objective means to measure sparkplug wire insertion forces.
• This approach enables quantification of design, lubricant, and pre-working effects on seating forces.
• The findings support improved design and manufacturing processes for sparkplugs and similar components.