Spark Plug Thread Formation Position Control
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Solution Overview
Problem
Existing spark plug manufacturing apparatuses experience variations in thread formation start position due to workpiece displacement during the feeding process, leading to inconsistent thread formation.
Innovation Solution
A manufacturing apparatus that includes a position measurement unit to non-contact measure the ground electrode's position and a die control unit to adjust the dies' working phase based on the measured position, ensuring accurate thread formation without physical contact, allowing for precise adjustment and consistent thread start position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a feeding unit is used to feed the workpiece to the holding unit, then the workpiece can be supplied continuously for manufacturing, but the workpiece experiences displacement during feeding which causes variation in thread formation start position
Solution Approach 1:
The position measurement unit measures the workpiece position before thread formation begins, and the die control unit adjusts the die working phase in advance based on this measurement. This preliminary measurement and adjustment eliminates the negative effect of workpiece displacement during feeding, ensuring accurate thread formation start position while maintaining continuous production capability
Solution Approach 2:
The position measurement unit provides feedback information about the actual workpiece position to the die control unit, which then adjusts the die working phase accordingly. This closed-loop feedback system compensates for workpiece displacement variations, maintaining manufacturing precision throughout continuous production
2Measurement precision
If the working phase of the dies is adjusted based on physical contact measurement, then the position can be accurately detected, but the workpiece may be displaced or damaged during contact measurement
Solution Approach 1:
The position measurement unit replaces mechanical contact-based position detection with a non-contact measurement system. This optical or electromagnetic measurement method accurately detects workpiece position without physical contact, eliminating the risk of workpiece displacement or damage during measurement while maintaining high measurement precision
Solution Approach 2:
The position measurement unit acts as an intermediary between the workpiece and the die control unit, providing position information without direct mechanical interaction. This intermediary measurement system enables accurate position detection while isolating the workpiece from any forces that could cause displacement or damage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables precise and consistent thread formation on the spark plug's metal shell, reducing variations and improving the manufacturing process's accuracy and reliability.
Implementation Method 1
the position measurement unit measures the position of the ground electrode part by emitting laser light to the ground electrode part from a direction perpendicular to the center axis of workpiece
Data Source
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AI summary
There is provided a manufacturing apparatus 200 of a spark plug by working of a workpiece W with dies 230a, 230b and 230c. The workpiece has a metal shell part 40P to be processed into a metal shell of the spark plug and a ground electrode part 50P to be processed into a ground electrode of the spark plug. In the manufacturing apparatus, a position of the ground electrode part is measured in a non-contact manner by a position measurement unit 240 in a state where the workpiece is held in position by a holding unit 210. The dies are controlled by a die control unit 250 so as to adjust the working phase of the dies relative to the workpiece based on the measured position of the ground electrode part and then effect working, with the dies, of the workpiece to form a thread portion on an outer circumferential surface 42P of the metal shell part.