Preform Injection Nozzle Vertical Rib Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing injection molding devices for producing preforms with laminated substrate and intermediate layers face challenges in maintaining consistent height positions of the leading edge, leading to fluctuations that affect the gas barrier property and delamination issues in biaxially stretched and blow-molded bottles.
Innovation Solution
The injection molding device employs a nozzle section with three coaxial cylindrical flow channels and vertical blocking rib pieces to segment the intermediate layer, adjusting the flow behavior and minimizing height differences between the maximum and minimum points of the leading edge, thereby ensuring uniform resin distribution and preventing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intermediate layer is laminated with substrate layers to form a laminated preform, then the gas barrier property is improved, but the delamination occurs under shearing force
Solution Approach 1:
The intermediate layer is segmented into multiple strips in the circumferential direction by vertical connecting zones, where the outer layer is connected directly with the inner layer. This segmentation prevents delamination from propagating throughout the entire structure by confining it to localized segments.
Solution Approach 2:
The vertical connecting zones create local regions where the substrate layers are directly connected without the intermediate layer, providing localized adhesion points that reinforce the bond between layers in critical areas while maintaining the gas barrier property in other regions.
2Reliability
If the intermediate layer is segmented into strips by vertical connecting zones, then the delamination is limited locally, but the manufacturing complexity increases
Solution Approach 1:
The vertical blocking rib pieces are pre-positioned in the middle flow channel at specific circumferential positions before resin injection. This preliminary arrangement ensures that the intermediate layer is automatically segmented into the desired number of strips during the molding process, achieving the delamination resistance function without requiring post-processing or complex assembly operations.
3Manufacturing precision
If the vertical blocking rib pieces are positioned to minimize height difference, then the leading edge uniformity is improved, but the positioning precision requirement increases
Solution Approach 1:
The vertical blocking rib pieces are designed to automatically segment the intermediate layer into a predetermined number of strips based on their circumferential positioning in the middle flow channel. The resin flow naturally adapts to the rib piece positions, creating vertical connecting zones that self-adjust to minimize leading edge height differences without requiring external measurement or adjustment mechanisms.
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3
AI summary
A technical problem of this invention is to minimize fluctuations in the height position of a leading edge of an intermediate layer of a preform in a circumferential direction when an injection molding device is used to mold the preform in a test tube by laminating substrate layers of a main resin with an intermediate layer, while segmenting the intermediate-layer resin in the circumferential direction into small streams A principal means of solving the above-described technical problem is a preform-molding device having a nozzle section comprising three cylindrical layer-forming flow channels, which include an inner flow channel and an outer flow channel for forming the substrate layers of the main resin, and a middle flow channel for forming the intermediate layer, and also comprising a predetermined number of vertical blocking rib pieces disposed at a downstream end of the middle flow channel, in parallel in the circumferential direction, so that the intermediate layer would be segmented in the circumferential direction into a predetermined number of vertically running streams, wherein flow behavior of the intermediate-layer resin flowing through the middle flow channel is adjusted by positioning the vertical blocking rib pieces in the circumferential direction so as to minimize a difference in height between a maximum height point and a minimum height point that appear in a leading edge of the intermediate layer of the preform.