Microwelded Metal Sheet Retention in Resin Injection Molding
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Solution Overview
Problem
The existing methods for molding composite parts with metal sheets in turbomachine compressors face challenges in retaining the metal strip in place due to the curved shape of the casing, leading to potential displacement during resin injection, which complicates the manufacturing process and affects the accuracy of the composite part's positioning.
Innovation Solution
A method involving the use of fastening means such as microwelding, electric resistance welding, or gluing to secure the metal sheet to the mold surface during resin injection molding, allowing for precise positioning and easy release after the composite part is formed, using a fiber preform to press and deform the sheet for better adherence, and employing a resin injection process under controlled pressure to bind the sheet to the composite body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the metal strip is positioned against a mold surface and held by the preform, then the implementation is simplified, but the resin pressure can move and deform the preform causing the strip to displace from its predetermined position
Solution Approach 1:
The retaining force is divided into multiple discrete microwelds distributed along the metal strip rather than relying on a single continuous preform constraint. This segmentation allows localized anchoring points that resist resin pressure more effectively while maintaining overall positioning accuracy.
Solution Approach 2:
The microwelds are created in advance before resin injection to securely anchor the metal strip to the mold surface. This preliminary fastening action ensures the strip remains fixed during the subsequent resin injection process, preventing displacement despite the applied pressure.
2Strength
If adhesive is used to attach the metal strip to the composite wall after molding, then the strip can be secured, but the positioning process becomes complicated due to the curved shape of the casing
Solution Approach 1:
The mechanical adhesive bonding process is replaced with microwelding technology that creates direct metal-to-mold fastenings. This substitution eliminates the need for complex positioning and adhesive application procedures, particularly benefiting curved surfaces where adhesive coverage and bonding quality are difficult to control.
Solution Approach 2:
The attachment method transitions from chemical bonding (adhesive) to thermal/mechanical bonding (microwelds). This parameter change in the joining mechanism simplifies the overall process by eliminating adhesive application, curing time, and positioning complexity while maintaining strong attachment.
3Reliability
If multiple fastening means are used to secure the metal sheet, then the sheet remains in place during resin injection, but the manufacturing process becomes more complex and material expenditure increases
Solution Approach 1:
Instead of uniformly distributing complex fastening mechanisms across the entire metal sheet, microwelds are applied at specific localized points along the strip. This local quality approach provides sufficient retention reliability at critical anchoring positions without the complexity and material cost of comprehensive fastening systems.
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 simplifies the retention and accurate positioning of the metal sheet within the mold, ensuring the sheet remains in place during resin injection and solidification, facilitating the removal of the composite part while minimizing the need for extensive fastening, thus improving the manufacturing efficiency and reducing material expenditure.
Implementation Method 1
Fastening means such as microwelding, electric resistance welding, or gluing to secure the metal sheet to the mold surface
Implementation Method 2
Fastening means such as microwelding, electric resistance welding, or gluing to secure the metal sheet to the mold surface
Implementation Method 3
Fastening means such as microwelding, electric resistance welding, or gluing to secure the metal sheet to the mold surface
Implementation Method 4
employing a resin injection process under controlled pressure to bind the sheet to the composite body
Data Source
AI summary
The present application relates to a method of injection molding a resin such as a RTM mold. The method enables to manufacture a composite part comprising a resin body and a sheet or strip, forming a surface of the composite part. The composite part can be an annular compressor casing of an axial turbomachine, with a composite annular wall. The method includes the steps of: (a) placing and holding the sheet against a mold surface by fastening means such as welds or microwelds; (b) injection and solidification of the resin in the mold so as to form the body by binding it to the sheet; (c) release of the sheet by the fastening means when a release force is exerted on the composite and release part of the composite part.