Mold Stack Air Valve for Consistent Ejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current injection molding technologies face challenges in achieving efficient and predictable ejection of molded articles due to uneven air pressure distribution, leading to inconsistent molding cycles and reduced operating speeds.
Innovation Solution
The design of a mold stack with a pneumatic structure that utilizes air channels and valves to control air flow, ensuring consistent air pressure behind the molded article and venting overpressure, allowing for predictable and repeatable ejection profiles by aligning air portals and vent channels with the movement of the stripper sleeve and core inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air is introduced through axial air passageways between forming pin and pin sleeve, then ejection forces are reduced and operating speeds increase, but air pressure distribution becomes uneven leading to inconsistent molding cycles
Solution Approach 1:
The air delivery system is segmented into multiple independent air channels (first air channel, second air channel, third air channel) that distribute air to different regions of the molded article. This segmentation ensures uniform air pressure distribution across the entire article, preventing inconsistent expansion and ensuring reliable, consistent ejection cycles while maintaining high operating speeds.
Solution Approach 2:
Different air channels are positioned to deliver air to specific local regions of the molded article (e.g., first air channel to first region, second air channel to second region). This local quality approach ensures that each region receives appropriate air pressure independently, achieving uniform overall pressure distribution and consistent molding cycles.
2Force
If pressurized air is introduced to expand the molded article during ejection, then ejection forces are significantly reduced, but excessive cooling is still required prior to ejection
Solution Approach 1:
Air is introduced into the molded article before ejection occurs, allowing the article to expand preliminarily while still attached to the forming pin. This preliminary expansion reduces the mechanical forces required for subsequent ejection, and because the expansion occurs during the molding cycle rather than requiring post-ejection cooling, the overall cooling requirement is reduced.
3Reliability
If multiple air channels are used to improve pressure distribution, then molding cycle consistency improves, but device complexity increases
Solution Approach 1:
Multiple air channels are merged into a single integrated air delivery system that is incorporated within the mold stack structure. The channels are combined in such a way that they work together as a unified system, reducing overall device complexity while still providing the benefits of distributed air pressure for consistent molding cycles.
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 enables efficient and predictable ejection of molded articles, reducing the need for excessive cooling and allowing for increased operating speeds by maintaining consistent air pressure and venting overpressure, resulting in improved molding cycle efficiency.
Implementation Method 1
To assist in ejecting the molded article from the inner core, compressed air is being routed there behind
Implementation Method 2
The seal member is configured to open and close at least one air valve defined between the first stack member and the second stack member
Implementation Method 3
The vent channel is configured to remove overpressure from behind the molded article
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed herein, amongst other things is a first stack portion (112, 212) of a mold stack (110, 210) for use in an injection mold (100, 200). The first stack portion (112, 212) includes a first stack member that is configured to define a molding cavity (116, 216) in cooperation with a second stack portion (114, 214) of the mold stack (110, 210), a second stack member that is movable relative to the first stack member, and an air valve (160, 260) is defined between the first stack member and the second stack member, the air valve (160, 260) being selectively actuatable with relative movement of the first stack member and the second stack member.