Intermediate Resin Sheet Processing for Heat Shrinkage Correction

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Solution Overview

Problem

Current methods for manufacturing resin sheets result in significant material waste and printing misalignment due to unpredictable heat shrinkage rates, leading to inefficiencies in the production process.

Innovation Solution

Implementing an intermediate processing method using a computerized process management system that segments extruded resin sheets into areas with specific shrinkage rate data, allowing for targeted corrections in processing conditions for each area, including coating and printing, to accurately predict and adjust for shrinkage before heat press processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If heat press processing is performed on extruded resin sheets without intermediate processing, then the processing flow is simple, but the shrinkage rate varies significantly (1-5%) leading to poor manufacturing precision

Engineering Contradiction:
Improvedimensional accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies intermediate processing between extrusion and heat press processing to pre-correct dimensional variations and shrinkage characteristics of resin sheets. This preliminary action modifies the sheet properties before final forming, reducing shrinkage rate variation from 1-5% to within acceptable tolerances and improving manufacturing precision without requiring complete process redesign

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the resin sheet processing into distinct stages: extrusion, intermediate processing, and heat press processing. By dividing the overall process and applying specific corrections at the intermediate stage, the system addresses dimensional variations in different regions of the sheet, thereby improving final product accuracy while maintaining manageable process complexity

Inventive Principle:
Principle #1Segmentation

2Loss of substance

If the entire resin sheet is processed with uniform conditions, then the processing is simple, but material waste increases due to unpredictable shrinkage in different areas

Engineering Contradiction:
Improvematerial wasteVSAvoidprocessing system complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent implements area-specific processing conditions in the intermediate processing stage, where different regions of the resin sheet receive customized corrections based on their individual shrinkage characteristics. This local quality approach allows precise control of dimensional variations in each area, reducing material waste by ensuring only necessary corrections are applied rather than over-processing the entire sheet

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system incorporates measurement and correction mechanisms that detect dimensional variations and shrinkage rates in different areas of the resin sheet, then apply targeted intermediate processing corrections. This feedback loop enables the system to adapt processing parameters to actual sheet conditions, minimizing material waste while managing processing complexity through automated control

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If coating and printing are performed before heat press processing without shrinkage correction, then the production flow is straightforward, but printing misalignment occurs due to shrinkage

Engineering Contradiction:
Improveprinting alignment accuracyVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs intermediate processing including coating and printing with pre-calculated shrinkage corrections before heat press processing. By applying correction values that anticipate the shrinkage behavior, the system ensures printing alignment accuracy is maintained throughout the subsequent heating and forming stages without requiring rework or adjustment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system modifies processing parameters such as coating thickness, printing position, and curing conditions in the intermediate stage based on predicted shrinkage characteristics. These parameter changes are calculated to compensate for upcoming shrinkage during heat press processing, ensuring final product accuracy while maintaining continuous production flow and efficiency

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

This approach reduces material and coating agent waste, minimizes printing misalignment, and enhances the accuracy of resin sheet production by accounting for individual area variations in shrinkage rates and processing conditions.

Implementation Method 1

a resin material can be subjected to extrusion molding while being heated to form a strip-like extruded resin sheet

Methodology Applied
Scientific EffectExtrusion: Extrusion

Implementation Method 2

a so-called heat press processing is required to heat, press, and shape a resin sheet

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

the residual stress, etc. experienced during extrusion change, which could cause a change in the shrinkage rate due to heat

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP4209328B1Intermediate processing method for extruded resin sheet and thermal press processing method for intermediate resin sheet in which intermediate processing is applied to extruded resin sheet
Publication Date: 2025.03.26 TOYOTA INDUSTRIES CORP
  • EP4209328B1 patent drawingFigure 1
  • EP4209328B1 patent drawingFigure 2
  • EP4209328B1 patent drawingFigure 3

AI summary

A process management system (1) having a computer is configured to virtually segment a strip-like, extrusion-molded resin sheet (W) subjected to extrusion molding into a plurality of individual areas corresponding to a plurality of resin sheets. Each individual area is further virtually segmented into a plurality of segmented areas. Shrinkage rate related information related to shrinkage rate of each segmented area is acquired for each segmented area. When implementing an intermediate processing, the process management system implements the intermediate processing with processing conditions corrected for each individual area based on the shrinkage rate related information for each individual area and for each segmented area, and heat press processing condition information, which are processing condition information of the heat press processing.