Forged Iron Golf Club Head With Continuous Grain Flow

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Solution Overview

Problem

There is a demand in the golf club market for iron golf clubs with enhanced feel, and existing forging methods do not effectively maintain continuous grain flows to achieve this.

Innovation Solution

A method for manufacturing an iron golf club head by forging a single round rod member using a pair of dies to form a body and neck as a single piece, where the heated material is blocked at the sole side to prevent flow-out and direct grain flows from the neck to the toe, resulting in a higher ratio of grain flows within the head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional forging methods are used to manufacture iron golf club heads, then the manufacturing process can be completed, but the grain flows are not effectively maintained to provide enhanced feel

Engineering Contradiction:
Improvefeel qualityVSAvoidgrain flow continuity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The forging process is divided into multiple sequential steps (first forging, second forging, third forging) with each step serving a specific purpose in maintaining and directing grain flow. The first forging creates initial grain structure, the second forging refines it, and the third forging finalizes the continuous grain flow pattern from neck to toe, thereby resolving the contradiction between manufacturing feasibility and grain flow continuity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rod member undergoes preliminary drawing treatment before forging to pre-orient the grain structure. This preliminary action ensures that the grain flows are already positioned favorably before the forging process begins, making it easier to maintain continuous grain flows throughout subsequent forging operations and improving the final feel quality.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the heated material is allowed to flow out freely from parting surfaces during forging, then the forging process is simpler, but the grain flows are disrupted and feel quality deteriorates

Engineering Contradiction:
Improvefeel qualityVSAvoidforging process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Different regions of the die are designed with different functions: the parting surface allows material flow in certain areas while the sole side prevents flow-out to maintain grain continuity. This localized control of material flow ensures that grain flows remain continuous from neck to toe while still allowing the forging process to proceed efficiently, resolving the contradiction between ease of manufacture and feel quality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The die structure acts as an intermediary that controls and directs the flow of heated material during forging. By designing specific die features (such as restricted flow paths at the sole side), the die mediates between the need for simple manufacturing processes and the requirement for continuous grain flows, enabling both objectives to be achieved simultaneously.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If multiple machining and forging stages are used to form difficult locations, then manufacturing precision improves, but production time and process complexity increase

Engineering Contradiction:
Improveformation accuracyVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The forging process is designed to maintain continuous useful action throughout all stages, with each forging step building upon the previous one without interruption. The sequential forging steps (first, second, and third forging) continuously refine the grain structure and shape the head in a coordinated manner, achieving high precision while maintaining manufacturing efficiency by eliminating idle time and redundant operations.

Inventive Principle:
Principle #20Continuity of useful action

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

This method effectively encloses grain flows around the ball striking portion, providing a more excellent feel by maintaining a higher density and continuity of grain flows, thereby increasing the duration of the ball hitting sound.

Implementation Method 1

a method for manufacturing an iron golf club head by forging a single round rod member with a pair of dies

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

grain flows extend from the neck to a toe of the body, and a ratio of the number of grain flows included in the iron golf club head to the number of grain flows included in the single material is higher than 97%

Methodology Applied
Scientific EffectGrain flow:

Implementation Method 3

the heated material is prevented from flowing out from parting surfaces of the respective dies at a sole side of the body in the pair of dies, and the heated material blocked at the sole side in the pair of dies flows toward each of a toe of the body and the neck in the pair of dies

Methodology Applied
Scientific EffectMaterial flow control:

Data Source

PatentEP3603756B1Iron golf club head production method, iron golf club head, and iron golf club
Publication Date: 2024.07.10 MIZUNO CORPORATION
  • EP3603756B1 patent drawingFigure 1~2
  • EP3603756B1 patent drawingFigure 3~5
  • EP3603756B1 patent drawingFigure 6~7

AI summary

Provided is a method for manufacturing an iron golf club head (10) by forging a single round rod member with a pair of dies (60) to form, as a single piece, a body (12) forming a ball striking portion and a neck (11) into which a shaft is to be inserted. The method includes: a first step of heating the single round rod member into a heated material; a second step of placing the heated material in the pair of dies (60); and a third step of forging the heated material placed in the pair of dies (60). In the third step, the heated material is prevented from flowing out from parting surfaces of the respective dies at a sole side of the body in the pair of dies (60), and the heated material blocked at the sole side in the pair of dies (60) flows toward each of a toe of the body and the neck in the pair of dies.