Coil Spring Coiling With Laser-Heated Wire Cutting Precision

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing coil spring forming machines face issues with responsiveness of high-frequency heating for cutting, adverse effects on cutting tools, and challenges in maintaining consistent forming accuracy due to partial heating of wires. Additionally, laser-based cutting systems face problems with spatter and uneven application of laser light.

Innovation Solution

A coiling machine that uses laser heating to create a heated portion of the wire, which is then cut using a cutter, resulting in a quench-hardened zone and a heat-affected zone. This process allows for precise cutting and improved spring quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If high-frequency heating is used to heat the cutting portion, then the cutting portion can be heated, but the responsiveness of heating is not good and the wire is coiled in the state where the wire is partially heated

Engineering Contradiction:
Improveheating temperature of cutting portionVSAvoidforming accuracy of spring
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent replaces high-frequency heating (electromagnetic induction heating) with laser heating (optical energy conversion to thermal energy). The laser beam directly irradiates the cutting portion, providing rapid and localized heating with high responsiveness, eliminating the partial heating issue that affected spring forming accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating method from conventional high-frequency heating to laser heating, altering the thermal input parameters. Laser heating provides more concentrated and controllable thermal energy, achieving uniform heating of the cutting portion without the responsiveness and precision problems of high-frequency heating.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If high-frequency heating is used to heat the cutting portion, then the cutting portion can be heated, but the members used for cutting are adversely affected by the high-frequency heating

Engineering Contradiction:
Improveheating temperature of cutting portionVSAvoidadverse effects on cutting members
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes laser heating for high-frequency heating, replacing electromagnetic induction with direct optical irradiation. The laser beam heats only the wire surface at the cutting portion without generating electromagnetic fields that could interfere with or damage the cutting members, eliminating the harmful thermal effects on cutting tools.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If high-power laser light is used to cut the wire, then the wire can be cut, but spatter resulting from laser light irradiation may occur and laser light can be applied to not only the wire, but also to various parts of the manufacturing device

Engineering Contradiction:
Improvecutting capabilityVSAvoidspatter and laser light application to device parts
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes laser heating parameters (power, duration, focal point) to heat the wire to a suitable temperature for cutting without melting or vaporizing it. This controlled thermal approach eliminates spatter generation and prevents laser light from damaging device components, while still achieving effective cutting when combined with the cutting blade.

Inventive Principle:
Principle #35Parameter changes

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 easy cutting of helically shaped wires, reduces wear on cutting tools, and enhances the quality and consistency of coil springs by ensuring precise cutting and reduced residual stress.

Implementation Method 1

a laser light irradiation unit configured to irradiate the helically shaped wire with laser light

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

the first end includes a first irradiation scar of laser light, the first irradiation scar includes a quench-hardened zone the hardness of which is higher than a base material of the wire

Methodology Applied
Scientific EffectQuench hardening: Phase Change

Data Source

PatentEP3922377B1Coiling machine, method for manufacturing coil spring, and coil spring
Publication Date: 2025.01.22 NHK SPRING CO LTD
  • EP3922377B1 patent drawingFigure 1
  • EP3922377B1 patent drawingFigure 2~3
  • EP3922377B1 patent drawingFigure 4

AI summary

A coiling machine 100 includes a laser heating machine 20 configured to irradiate a wire 1 formed into a helical shape with laser light to thereby heat a part of the wire 1, and cutting components 30 configured to cut a portion 1V of the wire after the irradiation of the laser light is stopped, a temperature of the portion being higher than before irradiated with the laser light.