Mold Cavity Surface Heating via Segmented Insert and Fluid Passage
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Solution Overview
Problem
Existing mold assembly technologies face challenges in preventing weld lines during the injection molding process, particularly due to temperature control issues, which lead to defects in the molded product's appearance and prolonged molding cycle times.
Innovation Solution
A synthetic resin molding mold assembly with a mold insert divided into an insert front piece and an insert rear piece, featuring a fluid passage that allows for the placement of electric heaters close to the cavity surface, enabling rapid and uniform heating without temperature variations, and allowing for a three-dimensional contour adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mold assembly is heated to a relatively higher temperature to prevent weld lines, then the appearance quality of the molded product is improved, but the cooling time becomes relatively longer, resulting in a longer molding cycle time
Solution Approach 1:
The mold insert is divided into an insert front piece with a cavity surface and an insert rear piece without the cavity surface. The fluid passage is formed to pass through the insert front piece in the vicinity of the cavity surface and extends from the rear surface of the insert rear piece. This segmentation allows independent control of heating zones and optimizes both appearance quality and molding cycle time.
Solution Approach 2:
The fluid passage is designed to pass through the insert front piece in the vicinity of the cavity surface rather than being positioned far from it. This three-dimensional arrangement allows the heating fluid to be in close proximity to the cavity surface, enabling rapid and uniform heating without requiring excessive temperature increases that would prolong cooling time.
2Ease of manufacture
If hot water/cold water switching system is used to control mold temperature, then the installation cost is reduced, but the temperature control response is not sharp and the upper limit temperature is restricted
Solution Approach 1:
The patent replaces the mechanical hot water/cold water switching system with an electric heater system. The electric heater can be rapidly switched on and off, providing sharp temperature control response, and can achieve higher temperature limits without the restrictions of water-based systems. This substitution maintains ease of manufacture while significantly improving temperature control performance.
3Device complexity
If the fluid passage is positioned far from the mold surface, then the mold assembly structure is simpler, but the temperature control efficiency is reduced
Solution Approach 1:
The fluid passage is designed to pass through the insert front piece in the vicinity of the cavity surface, utilizing the third dimension (depth/thickness of the insert piece) to position the heating fluid close to the cavity surface. This arrangement maintains relatively simple overall structure while significantly improving temperature control efficiency through reduced thermal resistance.
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 solution prevents weld lines by ensuring even and rapid heating of the mold cavity surface, improving the appearance quality of the molded product and reducing molding cycle time, while maintaining the mold assembly's physical strength and avoiding rust.
Implementation Method 1
electric heater disposed in the vicinity of any portion of the mold cavity to permit a mold piece of the assembly to be rapidly heated
Data Source
AI summary
A synthetic resin molding mold assembly, is provided for rapidly heating a cavity surface without suffering from any temperature variation in the cavity surface when a temperature of the cavity surface increases; this condition is not affected by a contour of the cavity surface; and, may prevent any weld line from occurring without prolonging a molding cycle time. A mold insert is employed that is divided into an insert front piece with the cavity surface and an insert rear piece without the cavity surface. A fluid passage is formed to pass through the front piece in the vicinity of the cavity surface and extends from a rear surface of the rear piece to pass there-through toward the cavity surface, receives an electric heater therein, and is then closed with the rear piece to dispose the heater in a deepest portion of the fluid passage.