Graphite Heater Unit for Thermoplastic Resin Welding

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Solution Overview

Problem

Conventional welding devices for thermoplastic resins require longer times and waste energy due to the use of metal plates with built-in heaters, which act as inefficient heat capacity bodies.

Innovation Solution

A welding device with a graphite heater unit sandwiched between insulating layers and a contact layer, providing efficient heat transfer and minimizing heat loss, along with inline plates and side blocks for precise positioning and displacement prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a metal plate with built-in heater is used for welding, then the heating function is achieved, but the welding time increases and energy is wasted due to the metal plate acting as a useless heat capacity body

Engineering Contradiction:
Improveenergy efficiencyVSAvoidwelding time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent extracts the heat generating function from the metal plate structure and concentrates it into a thin-film heater layer. This separates the heating function from the structural support function, eliminating the useless heat capacity of the metal plate while maintaining the necessary structural integrity through the reinforcement plate and mold configuration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the thermal conductivity parameter by using a thin-film heater with high electrical resistance and low thermal mass, replacing the conventional metal plate heater. This parameter change reduces the heat capacity from kilograms to grams, dramatically reducing the time to reach operating temperature while maintaining effective heating.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If a metal plate with built-in heater is used, then heating is achieved, but the heat capacity body becomes useless increasing the rise and fall time of temperature

Engineering Contradiction:
Improveheating speedVSAvoidtemperature rise and fall time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The patent employs a thin-film heater structure that is extremely thin (microscopic thickness) compared to conventional metal plates. This thin-film configuration reduces the thermal mass and heat capacity dramatically, allowing the heater to reach operating temperature quickly and respond rapidly to control changes, thus reducing the temperature rise and fall time.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent replaces the mechanical/heavy metal plate-based heating system with an electrical thin-film heating system. This substitution eliminates the inertial effects of the metal plate's heat capacity, enabling rapid temperature changes and faster response to welding process requirements.

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

3Productivity

If conventional heating methods are used, then welding can be performed, but the process is not energy-efficient due to heat loss and unnecessary heat capacity

Engineering Contradiction:
Improvewelding efficiencyVSAvoidenergy waste
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent introduces a heat insulating layer as an intermediary between the thin-film heater and the surrounding environment. This insulating layer prevents heat loss to the mold and surrounding structures, directing thermal energy specifically to the welding area and improving overall energy efficiency while maintaining high productivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration enables faster and more energy-efficient welding by reducing heat capacity and enhancing thermal conductivity, while preventing material displacement and inclination during the welding process.

Implementation Method 1

a sheet-like heat generating body configured to generate heat by electric power

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the contact layer has thermal conductivity of 10 W/m×K or greater at normal temperature

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4205953B1Welding device and welding method
Publication Date: 2024.09.11 MITSUBISHI HEAVY IND LTD
  • EP4205953B1 patent drawingFigure 1
  • EP4205953B1 patent drawingFigure 2
  • EP4205953B1 patent drawingFigure 3

AI summary

Provided are a welding device and a welding method that can realize efficient welding in terms of time and in terms of energy. The embodiment includes: a first graphite heater 110 and a second graphite heater 120 that come into contact with a first member 210 and a second member 220; and a first die 130 and a second die 140 that interpose the first and second graphite heaters 110, 120 between each of the first and second members 210, 220 and each die. The first and second graphite heaters 110, 120 have graphite sheets 114, 124 that generate heat by electric power, electrically insulating materials 113, 123, outer covers 111, 121, and inner covers 112, 122 and are configured such that structures of the graphite sheets 114, 124 and the electrically insulating materials 113, 123 interposing the graphite sheets are interposed between outer covers 111, 121 and inner covers 112, 122.