Blade Mold Cold Runner Eliminates Runner Rubber
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Solution Overview
Problem
The existing methods for producing blades for office appliances, such as developer amount limiting blades, result in the formation of unnecessary runner rubber due to the curing of heat-curable materials in the mold, requiring additional process steps and increasing material and discarding costs.
Innovation Solution
A mold design that incorporates a cold runner to maintain the heat-curable material at a temperature lower than its curing temperature, preventing it from curing, along with heat insulation and a closure pin to prevent leakage and burr formation, allowing for the elimination of runner rubber and improved cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat-curable material is used to produce the resilient member, then the material achieves proper curing and adhesion to the base plate, but runner rubber forms in the mold requiring additional removal steps and increasing waste
Solution Approach 1:
The mold cavity is segmented into a hot cavity region for curing the resilient member and a cold runner region for preventing rubber formation. This spatial segmentation allows different thermal conditions in different regions of the mold, enabling the resilient member to cure properly while preventing runner rubber formation through the cold trap mechanism.
Solution Approach 2:
A cold trap (cold runner) acts as an intermediary element between the material injection point and the hot mold cavity. This cold trap serves as a buffer zone that intercepts the heat-curable material before it enters the heating means, preventing it from curing in the runner while allowing it to reach the cavity for proper curing.
2Ease of manufacture
If the mold is heated to cure the heat-curable material, then adhesion is achieved, but runner rubber forms requiring additional process steps
Solution Approach 1:
The harmful curing reaction is extracted from the runner region by introducing a cold trap. The cold trap removes the heat-curable material from the heated zone before it can cure in the runner, thereby eliminating the need for additional runner removal steps while maintaining the heating process for proper adhesion in the cavity.
Solution Approach 2:
The cold trap converts the harmful effect of premature curing into a beneficial separation mechanism. By deliberately creating a cold zone in the runner, the material is prevented from curing where it would cause problems, while the same material flows into the hot cavity where curing is desired, thus converting the potential harm of premature curing into a useful process control mechanism.
3Strength
If the resilient member is adhered to the base plate using heat-curable material, then bonding strength is achieved, but material leakage and burr formation occur
Solution Approach 1:
The cold trap serves as an intermediary containment structure that prevents material leakage and burr formation. By providing a controlled cold zone before the material enters the hot cavity, excess material is contained and prevented from leaking into unwanted areas, while the material that does enter the cavity cures properly to achieve the desired bonding strength.
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 effectively eliminates the formation of undesirable runner rubber, reducing material waste and process complexity, while maintaining the quality of the molded product with improved heat efficiency and precision.
Implementation Method 1
the heat-curable material in the cavity is heated by a heating means (not shown), which is provided for the mold 80, and adhered to the base plate 91
Implementation Method 2
at least a part of the runner, including an outlet 14a thereof, is comprised of a cold runner 14 which maintains the heat-curable material at a temperature lower than a curing temperature of the heat-curable material
Data Source
AI summary
A mold for producing a blade for office appliances, wherein a resilient member made of a heat-curable material is adhered to a base plate. The mold includes a cavity corresponding to the resilient member of the blade, a space for placing the base plate adjacent to the cavity, a runner for passing the heat-curable material therethrough and injecting the heat-curable material into the cavity, and a heating means adjacent to the cavity, for causing curing of the heat-curable material in the cavity. At least a part of said runner, including an outlet thereof, is comprised of a cold runner for maintains the heat-curable material, which remains in the cold runner, at a temperature lower than its curing temperature.