Pressurized Slurry Additive Manufacturing for Rocket Motors
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Solution Overview
Problem
Existing additive manufacturing processes for rocket motors struggle with efficiently shaping and curing solid energetic materials into desired geometries without premature curing or 'globbing' during the deposition process.
Innovation Solution
An additive manufacturing process involving a pressurized vessel and nozzle system where a slurry of polyvinyl chloride, plasticizer, and solid energetic materials is heated and deposited, with controlled pressure and temperature to initiate solvation and curing, allowing for precise three-dimensional printing of rocket motor components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the slurry is heated to initiate solvation and curing, then the material forms desired geometries, but premature curing and globbing occur during deposition
Solution Approach 1:
The slurry is preheated to a temperature below the cure temperature (e.g., 50-150°C) before deposition to initiate solvation and improve flowability, but the curing reaction is delayed until after deposition by controlling the temperature to remain below the cure temperature during the deposition process. This preliminary heating action prepares the material without triggering premature curing.
Solution Approach 2:
The system dynamically adjusts temperature control based on the deposition stage: preheating before deposition, maintaining lower temperature during deposition to prevent globbing, and then heating after deposition to complete curing. This dynamic temperature management resolves the contradiction between needing heat for geometry formation and avoiding heat-induced premature curing.
2Productivity
If pressure is applied to feed slurry through the nozzle, then deposition efficiency improves, but material consistency deteriorates
Solution Approach 1:
The system changes the pressure parameter dynamically: applying higher pressure to feed slurry through the nozzle for efficient deposition, then reducing pressure to a lower level after deposition to maintain material consistency and prevent premature curing. This parameter change resolves the contradiction between deposition efficiency and material consistency.
3Productivity
If heating temperature is increased to accelerate curing, then manufacturing speed improves, but premature curing and globbing increase
Solution Approach 1:
The slurry is preheated to a temperature below the cure temperature to initiate solvation and prepare the material for deposition, but the temperature is controlled to remain below the cure temperature during deposition to prevent premature curing. This preliminary heating without exceeding the cure temperature resolves the contradiction between curing speed and deposition stability.
Solution Approach 2:
The heating process is divided into periodic stages: preheating before deposition, temperature maintenance during deposition, and post-deposition heating for curing. This periodic temperature control allows accelerated curing after deposition while preventing premature curing during deposition.
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 the precise formation of solid energetic materials into desired geometries with reduced premature curing and 'globbing', facilitating the creation of complex shapes and structures for rocket motors with improved consistency and efficiency.
Implementation Method 1
A heating block upstream of the nozzle may be used to heat the slurry to a temperature equal to or greater than a cure temperature of the slurry to commence a solvation of a polyvinyl chloride component of the slurry
Implementation Method 2
The plastisol and solid energetic material are mixed to form a slurry that is pressurized and fed from a pressurized vessel to the nozzle
Data Source
Figure 1~2
AI summary
An additive manufacturing process includes pressurizing and heating a slurry, flowing the pressurized heated slurry through a nozzle, and depositing the slurry in a predetermined pattern.