Injection Mold Cavity Sensing for Consistent Film Hinges
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Solution Overview
Problem
Existing injection molding technologies struggle to maintain consistent mechanical properties in molded parts, particularly with bioplastics and recycled materials, due to variations in material properties and contamination, which can lead to defects in critical areas like film hinges.
Innovation Solution
The use of sensors arranged in the cavity to measure viscosity and pressure before and after a constriction in the mold, allowing a controller to adjust the injection process to maintain optimal viscosity and pressure conditions, ensuring consistent mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sensors are arranged in the cavity to measure viscosity and pressure before and after constriction, then manufacturing precision of molded parts is improved, but device complexity increases
Solution Approach 1:
The cavity is segmented into multiple measurement zones by arranging sensors at specific locations - one sensor arrangement before the constriction and another after the constriction. This segmentation allows independent measurement of viscosity and pressure changes across the constriction, enabling precise control of material flow and consistent mechanical properties in molded parts.
Solution Approach 2:
The controller receives real-time data from the sensor arrangements measuring viscosity and pressure before and after the constriction, and adjusts injection parameters accordingly. This feedback mechanism ensures that despite variations in material properties (especially with bioplastics and recycled materials), the mechanical properties of molded parts remain consistent by dynamically compensating for viscosity changes across the constriction.
2Reliability
If viscosity is adjusted during injection molding, then reliability of molded parts is improved, but use of energy increases
Solution Approach 1:
The injection molding process employs dynamic adjustment of viscosity during injection by controlling material temperature and flow conditions. The controller modifies injection parameters in real-time based on sensor feedback from before and after the constriction, allowing the system to adapt viscosity dynamically rather than maintaining constant high energy input, thus improving reliability while managing energy consumption efficiently.
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 ensures that the mechanical properties of molded parts, especially in areas with constrictions like film hinges, meet specified criteria, reducing defects and ensuring consistent quality.
Implementation Method 1
A first sensor arrangement (15) is arranged in a cavity wall (8) of the first cavity section (9) before the constriction (11) and a second sensor arrangement (16) in a cavity wall (8) of the second cavity section (10) behind the constriction (11)... the controller (17) is configured to determine during injection the viscosity of the melted plastic material in the area of the constriction (11)
Implementation Method 2
The first sensor arrangement (15) and the second sensor arrangement (16) each comprise a temperature sensor (18) and/or a pressure sensor (19)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The disclosure is directed to an injection molding device (1) comprising at least one injection mold (2, 3) with a first mold half (4) and a second mold half (5) during operation being displaceable with respect to each other in a first direction (z) be tween a closed position and an open position. The first mold half (4) and the second mold half (5) forming in the closed position at least one cavity (7) there be tween suitable to receive melted plastic material from an injection nozzle (13). The at least one cavity (7) comprises a first cavity section (9) and a second cavity section (10) which is interconnected to the first cavity section (9) by a constriction (11). Melted plastic material (21) is injected into the first cavity section (9) and travels from there via the constriction (11) into the second cavity section (10). A first sensor arrangement (15) is arranged in a cavity wall (8) of to the first cavity section (9) and a second sensor arrangement (16) is arranged in a cavity wall (8) of the second cavity section (10) to determine relevant parameters in relation to the constriction.