In-Mold Coating Runner and Flange Flow Control
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Solution Overview
Problem
Current injection molding techniques face challenges in efficiently coating multiple articles within multiple part cavities using a single injector while controlling the flow of in-mold coating composition to ensure only desired surfaces are coated, particularly in maintaining pressure and uniformity across different mold designs and conditions.
Innovation Solution
A molding apparatus with multiple mold cavities, featuring a first composition injector for molding and a second composition injector for in-mold coating, where the second injector is connected to the mold cavities to apply the coating composition, allowing for controlled flow and distribution using a runner section and containment flanges to ensure precise coating on desired surfaces without escaping through the parting line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single injector is used to coat multiple molded articles in multiple cavities, then device complexity is reduced, but controlling the flow of IMC composition to ensure precise coating on desired surfaces becomes more difficult
Solution Approach 1:
The mold cavity system is segmented into multiple cavities, each with dedicated runner sections and containment flanges that independently control IMC composition flow to specific articles. This allows a single injector to serve multiple cavities while maintaining precise coating control through localized flow management structures.
Solution Approach 2:
Each mold cavity is equipped with localized flow control features including runner sections and containment flanges positioned at specific locations to direct IMC composition flow onto desired surfaces of each article. This ensures that each article receives coating precisely where needed, even though all articles are coated by a single injector.
2Object-generated harmful factors
If the mold is kept closed during IMC composition injection, then material escape along the parting line is prevented, but the IMC composition must be injected under sufficient pressure to compress the article in all areas to be coated
Solution Approach 1:
The mold cavity geometry and runner section design are configured in advance to guide IMC composition flow onto desired surfaces of the articles before injection begins. Containment flanges are pre-positioned to direct flow patterns, allowing lower injection pressures to achieve effective coating without requiring excessive compression of the articles.
Solution Approach 2:
The containment flanges and runner sections create localized flow channels that concentrate IMC composition onto specific surfaces of each article. This localized delivery ensures adequate coating coverage without requiring uniform high pressure across the entire mold cavity, reducing overall injection pressure requirements.
3Productivity
If multiple articles are coated simultaneously in multiple cavities, then productivity is improved, but controlling the flow of IMC composition to ensure uniform coating on each article becomes more difficult
Solution Approach 1:
The injection system is segmented into multiple independent cavity systems, each with its own runner section and containment flange configuration. This segmentation allows the IMC composition to flow independently to each cavity, ensuring uniform coating distribution across multiple articles simultaneously while maintaining consistent coating quality in each cavity.
Solution Approach 2:
The containment flange and runner section design serves multiple functions: it directs IMC composition flow onto desired surfaces, prevents material escape, and ensures uniform distribution. This multi-functional design enables simultaneous coating of multiple articles with consistent quality using a single injector system.
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
Enables efficient and uniform in-mold coating of multiple articles using a single injector, maintaining pressure and ensuring only desired surfaces are coated, thereby improving the physical properties and appearance of molded thermoplastic articles while maintaining the integrity of the mold cavity.
Implementation Method 1
The compressibility of the molded article dictates how and where the IMC composition covers it. The process of IMC an injection molded article with a liquid IMC composition requires maintaining pressure on the movable mold half.
Implementation Method 2
using only a single injector to coat the multiple molded articles and/or (3) controlling the flow of the injected IMC composition on the multiple molded articles such that the multiple articles are only coated on desired surfaces or portions thereof.
Data Source
AI summary
A molding apparatus includes a mold (12,14) defining a plurality of mold cavities (34,36). Fluidly connected to the mold cavities (34,36) are one or more first composition injectors (30) and one or more second composition injectors (32) for delivery of, respectively, the molten material from which the molded article is to be formed and a composition to coat the article so formed.