Composite Turbine Blade Co-Molding at Adhesive Gel Point
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing composite blades for turbomachines face challenges in achieving optimal mechanical strength and secure attachment of metal shields due to improper timing and viscosity mismatch between resin and adhesive during the co-molding process.
Innovation Solution
A method involving the use of a polymerizable adhesive film interposed between the shield and preform, with resin injection timed to coincide with the adhesive's gel point to ensure proper bonding, optimizing the attachment and mechanical strength by regulating the resin injection cycle based on the adhesive's viscosity changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the adhesive is inserted between the shield and the leading edge of the vane to improve attachment, then the mechanical strength of the shield on the vane is enhanced, but the adhesive polymerizes too advanced at the time of resin injection reducing the mechanical strength
Solution Approach 1:
The adhesive is applied to the shield and preform before the resin injection process begins. The adhesive is allowed to remain in its polymerizable state until the optimal moment for resin injection, ensuring it is ready to bond but not yet cured. This preliminary positioning and timing of adhesive application resolves the contradiction by preparing the adhesive in advance while controlling its polymerization to occur at the right moment during the process.
2Temperature
If the mold is heated to high temperature for resin polymerization, then the resin polymerization is achieved, but the adhesive polymerization becomes too advanced reducing bonding effectiveness
Solution Approach 1:
The heating process is made dynamic and time-dependent rather than static. The mold temperature is controlled to increase gradually, and the resin injection is timed to occur at a specific temperature range before the adhesive reaches complete polymerization. This dynamic control of temperature and timing allows the process to adapt to the changing viscosity and polymerization state of the adhesive, resolving the contradiction between achieving resin polymerization and preventing premature adhesive curing.
Solution Approach 2:
The process utilizes changes in physical parameters, specifically temperature and time, to control the polymerization state of the adhesive. By monitoring and adjusting the mold temperature and resin injection timing, the process ensures that the adhesive reaches the optimal viscosity range for bonding at the moment of resin injection. This parameter control resolves the contradiction by transforming the thermal history into a controlled variable that prevents premature adhesive polymerization while ensuring complete resin curing.
3Manufacturing precision
If resin injection is delayed to allow adhesive positioning, then the adhesive positioning is improved, but the adhesive viscosity increases reducing co-bonding effectiveness
Solution Approach 1:
The process incorporates feedback control by monitoring the viscosity and polymerization state of the adhesive in real-time. Based on this feedback, the resin injection timing is adjusted to occur at the optimal moment when the adhesive has reached the desired positioning state but has not yet become too viscous for effective bonding. This feedback mechanism resolves the contradiction by continuously adapting the injection timing to the actual state of the adhesive, ensuring both proper positioning and effective co-bonding.
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
Ensures secure and optimal positioning of the shield on the blade, enhancing mechanical strength and resistance, while maintaining the integrity of the composite material.
Implementation Method 1
The adhesive usually starts to cure at a lower temperature than the resin. This temperature is reached when the mold is heated to the high temperature at which the resin is injected.
Implementation Method 2
Then resin is injected in a liquid state by maintaining a pressure on the injected resin while the part is polymerized by heating. During the polymerization method, under the effect of the heat, the injected resin passes successively from the liquid state to the gelled state and finally to the solid state.
Data Source
AI summary
A process for manufacturing a blade made of composite material for a turbomachine is provided. The blade includes an airfoil having a pressure side and a suction side which extend from a leading edge to a trailing edge of the airfoil. The blade further includes a metal sheath that extends along the leading edge of the airfoil. The process includes the steps of: a) placing a preform, made by three-dimensionally weaving fibers, in a mold, a polymerizable adhesive being inserted between the sheath and the edge of the preform; and b) injecting polymerizable resin into the mold to impregnate the preform so as to form the airfoil after solidifying, wherein the resin is injected within a time interval during which the adhesive reaches a freezing point.