Injection Molding Controller Selective Cavity Filling

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Solution Overview

Problem

The existing injection molding methods face issues with uneven cooling shrinkage and the generation of sink marks due to the lack of stock in secondary molding products, leading to defective products and material waste, especially when the entire lower cavity is filled with molten resin without a secondary product.

Innovation Solution

An injection molding machine with a controller that selectively fills cavity spaces based on stock availability, allowing for sequential insert molding and optimizing the filling of cavity spaces to prevent uneven cooling and reduce material waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the entire lower cavity is filled with molten resin when the secondary molding product is not in stock, then the cavity space is fully utilized, but uneven cooling shrinkage occurs and sink marks are generated on the surface of the molding product

Engineering Contradiction:
Improvecavity space utilizationVSAvoidsurface quality
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The invention applies local quality by differentiating the filling strategy between cavity spaces based on local conditions. When the secondary molding product is not in stock, the system selectively fills only the lower cavity space with molten resin while leaving the upper cavity space unfilled. This localized filling approach prevents uneven cooling shrinkage and sink marks in the upper cavity, thereby maintaining surface quality while still utilizing the lower cavity space effectively.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If the entire lower cavity is filled with molten resin when the secondary molding product is not in stock, then the cavity space is fully utilized, but defective products are manufactured and molding material is wasted

Engineering Contradiction:
Improvecavity space utilizationVSAvoidmolding material waste
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The system implements local quality control by selectively filling only the lower cavity space when the secondary molding product is not available, rather than filling the entire cavity. This prevents the formation of defective products in the upper cavity space, thereby reducing molding material waste while maintaining effective utilization of the lower cavity space for producing the primary molding product.

Inventive Principle:
Principle #3Local quality

3Productivity

If a two-step upper and lower structure with two cavity spaces is used for simultaneous filling, then productivity is improved, but the complexity of controlling selective filling increases

Engineering Contradiction:
Improvemolding cycle efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention applies dynamics by making the filling control adaptive and flexible rather than fixed. The controller dynamically adjusts the filling strategy based on real-time stock status of the secondary molding product. When stock is available, both cavity spaces are filled simultaneously; when stock is not available, only the lower cavity space is filled. This dynamic control maintains high productivity while managing complexity through intelligent decision-making rather than additional hardware.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback control by continuously monitoring the stock status of the secondary molding product and adjusting the filling operation accordingly. The controller receives feedback about inventory levels and automatically selects the appropriate filling pattern (full cavity filling or partial filling), thereby maintaining productivity while simplifying control through information-based decision-making rather than complex mechanical systems.

Inventive Principle:
Principle #23Feedback

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 improves the quality of the molding product by minimizing sink marks and waste, ensuring consistent material flow and uniform cooling, thereby enhancing the precision and efficiency of the molding process.

Implementation Method 1

an injection unit configured to fill a plurality of cavity spaces of a mold unit with a molding material

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

a nth molding product which is obtained by sequentially moving a molding product between n cavity spaces of the plurality of cavity spaces to perform insert molding

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP3747617B1Injection molding machine and injection molding system
Publication Date: 2022.06.01 SUMITOMO HEAVY IND LTD
  • EP3747617B1 patent drawingFigure 1
  • EP3747617B1 patent drawingFigure 2
  • EP3747617B1 patent drawingFigure 3

AI summary

An injection molding machine includes an injection unit which fills a plurality of cavity spaces of a mold unit with a molding material and a controller which controls the injection unit, in which an nth molding product which is obtained by sequentially moving a molding product between n (n is a natural number of 2 or more) cavity spaces of the plurality of cavity spaces to perform insert molding is molded as a finished product. The controller has a setting storage unit in which a setting of a control of filling the plurality of cavity spaces with the molding material is stored, and the setting storage unit stores a setting of a control to fill a predetermined cavity space of the plurality of cavity spaces with the molding material and of not filling a cavity space other than the predetermined cavity space with the molding material.