Two-Shot Injection Molding with Gate Occlusion
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Solution Overview
Problem
Traditional product development processes involving injection molding of polymeric articles are lengthy and costly, requiring multiple layers of plastic injection and expensive two-component machines.
Innovation Solution
A method that uses an injection molding machine with a movable mold core to direct two shots of molten material into a mold cavity, where the first shot forms a part that occludes a portion of the gate orifice area, allowing the mold core to be withdrawn and a second shot to fill the space left by the core, significantly reducing the time and cost by forming all or most layers in just two shots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional multi-layer injection molding is used, then complete polymeric articles can be formed, but the process takes 45 to 60 minutes and requires expensive two-component machines
Solution Approach 1:
The injection molding process is segmented into two distinct shots: a first shot that forms a base part with a gate occluding portion, and a second shot that forms a secondary part. This segmentation allows each shot to be optimized independently and enables the use of simpler single-shot machines rather than expensive two-component machines.
Solution Approach 2:
The first shot is performed preliminarily to form a base part that includes a gate occluding portion. This preliminary action creates the structural foundation and automatically occludes the gate for the second shot, eliminating the need for complex gate management systems and reducing overall process time to under 5 minutes.
2Manufacturing precision
If traditional multi-layer injection molding is used, then complete polymeric articles can be formed, but expensive two-component machines are required
Solution Approach 1:
The molding process is divided into sequential single-shot operations rather than requiring simultaneous multi-component injection. This segmentation allows the use of standard single-shot injection molding machines, which are significantly less expensive than two-component machines, while still achieving complete polymeric article formation.
Solution Approach 2:
The first shot automatically creates a gate occluding portion that serves the dual function of forming part of the article and blocking the gate for the second shot. This self-service mechanism eliminates the need for complex gate management systems and expensive specialized machinery.
3Manufacturing precision
If multiple shots are used to form layers, then complete articles can be formed, but warping increases and strength decreases
Solution Approach 1:
The first shot is designed to create a base part with specific local quality characteristics, including a gate occluding portion that ensures proper material flow control for the second shot. This localized structural feature improves overall part strength by ensuring complete filling and proper bonding between shots while minimizing warping.
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 method shortens the injection molding time from 45 to 60 minutes to under 5 minutes, produces polymeric blocks with superior physical characteristics, and allows for formation on less expensive single-shot machines, reducing warping and increasing strength.
Implementation Method 1
directing a first shot of molten material into a mold cavity to form a first part
Implementation Method 2
simultaneously occluding a portion of the gate orifice area with a mold core
Implementation Method 3
Once the first shot is solidified, then the mold core is withdrawn
Implementation Method 4
the mold core is withdrawn and a second shot is directed into the space previously occupied by the mold core
Implementation Method 5
a second shot of molten material is directed into the mold cavity through the second portion of the total orifice area
Implementation Method 6
The second shot of molten material is solidified to form a second part of the article
Data Source
Figure 1
Figure 2~3A
Figure 3B~3C
AI summary
The present invention relates to articles, systems, and methods for injection molding an article. The method includes directing a first shot of molten polymeric material into a mold cavity to form a first part while simultaneously occluding a portion of the gate orifice area with a mold core. Once the first shot is solidified, then the mold core is withdrawn and a second shot is directed into the space previously occupied by the mold core while a portion of the gate orifice area is occluded by the solidified first shot.