Direct-writing Polyimide Additive Manufacturing via UV Curing and Heat Treatment
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Solution Overview
Problem
Current polyimide additive manufacturing methods face challenges in achieving high mechanical strength, thermal stability, and low volume shrinkage, limiting the production of complex three-dimensional parts with precision.
Innovation Solution
A direct-writing polyimide additive manufacturing method involving ultraviolet curing of photosensitive polyimide ink followed by heat treatment, which reduces volume shrinkage through bonding and restraint between wires, resulting in a material with enhanced mechanical strength and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional molding and coating methods are used to prepare polyimide, then the material has excellent comprehensive properties, but the resolution, stability and precision are very limited
Solution Approach 1:
The patent replaces conventional mechanical molding and coating methods with a direct-writing additive manufacturing system that uses extrusion to deposit photosensitive polyimide material layer by layer, followed by UV curing to solidify the structure. This substitution enables precise control over the three-dimensional geometry while maintaining the excellent comprehensive properties of polyimide through controlled polymerization and crosslinking during the printing process.
2Productivity
If photocurable polyimide ink is used for DLP 3D printing, then rapid manufacturing is achieved, but the mechanical and thermal properties have a performance gap compared to conventional methods
Solution Approach 1:
The patent optimizes multiple parameters including the composition of photosensitive polyimide ink (with specific ratios of polyimide resin, monomer, and photoinitiator), extrusion speed, UV light intensity and wavelength, and heat treatment temperature and duration. By carefully controlling these parameters, the patent achieves both rapid manufacturing capability and mechanical/thermal properties that closely match conventional polyimide materials.
Solution Approach 2:
The patent develops a composite photosensitive polyimide ink system combining polyimide resin with specific monomers and photoinitiators. This composite formulation enables the material to undergo both polymerization and crosslinking during UV curing, resulting in a dense, strong structure that maintains high mechanical and thermal properties while enabling rapid additive manufacturing.
3Strength
If mask lithography technology with secondary heat treatment is used, then high mechanical strength and heat stability are achieved, but volume shrinkage is relatively large close to 50%
Solution Approach 1:
The patent incorporates photopolymerizable groups directly into the polyimide structure during the extrusion and UV curing process, creating a pre-crosslinked network that reduces subsequent volume shrinkage during heat treatment. This preliminary action of forming crosslinks before final heat treatment prevents the large volume shrinkage (close to 50%) that occurs with conventional mask lithography methods, while still achieving high mechanical strength and heat stability.
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
The method achieves a tensile strength of 80-180 MPa, volume shrinkage of 6%, and a glass transition temperature of 245-300°C, enabling the production of polyimide parts with improved mechanical and thermal properties.
Implementation Method 1
conducting ultraviolet curing immediately after the photosensitive polyimide ink is subjected to direct-writing extrusion
Implementation Method 2
heat-treating the polyimide precursor formed member obtained in step (1) to obtain the direct-writing polyimide AM material
Data Source
AI summary
A method for preparing a direct-writing polyimide additive manufacturing (AM) material includes (1) conducting ultraviolet curing immediately after the photosensitive polyimide ink is subjected to direct-writing extrusion, to obtain a polyimide precursor formed member; and (2) heat-treating the polyimide precursor formed member obtained in step (1) to obtain the direct-writing polyimide AM material. The direct-writing polyimide AM material obtained by using the method of the present invention has excellent comprehensive properties.