Offset Layer Slicing in Vat Photopolymerization for Multi-Material Parts
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Solution Overview
Problem
Traditional vat photopolymerization systems are limited in forming parts with multiple materials, as replacing materials in the vat is costly and time-consuming, restricting the ability to create parts with varied properties.
Innovation Solution
A method for vat photopolymerization additive manufacturing that involves alternating between two or more materials by positioning a platform with formed sections in different material tanks, allowing for the creation of parts with layers composed of materials having distinct optical, physical, or mechanical properties, and preventing material crashes through strategic positioning and irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single material is used in traditional VPP systems, then the process is simple and cost-effective, but the ability to create parts with varied material properties is limited
Solution Approach 1:
The build chamber is segmented into multiple material tanks, each containing a different photopolymer material. The platform can be positioned in different tanks to deposit different materials for different sections of the same layer, enabling multi-material part fabrication without requiring material replacement in a single vat
Solution Approach 2:
The VPP system is designed with universal capability to handle multiple materials simultaneously through multiple tanks. The same irradiation system and platform can work with different materials by simply changing the platform's horizontal position to access different material tanks, making the system versatile for creating parts with varied optical, mechanical, and physical properties
2Adaptability or versatility
If materials are replaced in the vat to form different sections, then multi-material parts can be created, but the process becomes time-consuming and costly
Solution Approach 1:
Multiple materials are prepared in advance in separate tanks before the building process begins. This preliminary preparation eliminates the need for time-consuming material replacement operations during layer formation, as all materials are readily available when needed
Solution Approach 2:
The system transitions from vertical layer-by-layer material deposition in a single vat to horizontal positioning across multiple tanks. By adding the horizontal dimension of platform movement between tanks, the system enables rapid material selection without the time penalty of draining and refilling a single vat
3Reliability
If sections are formed adjacent to each other in the same vat, then layer continuity is maintained, but material crashes occur during platform positioning
Solution Approach 1:
The continuous layer is segmented into multiple sections, each formed from different materials in different tanks. The gaps between sections correspond to the physical separation between tanks, eliminating the risk of material crashes while maintaining overall layer continuity through proper section spacing and positioning
Solution Approach 2:
The system uses air gaps or inert barriers between material tanks as intermediaries to prevent direct contact between different materials during platform transitions. This intermediary space allows the platform to move between tanks without causing materials from different tanks to crash into each other
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 production of parts with enhanced properties and reduced material crashes, thereby decreasing production costs and time, while allowing for the creation of complex structures with varied material properties.
Implementation Method 1
a vat or tank of a VPP system contains liquid monomers and oligomers that undergo cross-linking when exposed to light to thereby form a polymer layer
Data Source
AI summary
A method of additive manufacturing a part via vat photopolymerization (VPP) includes irradiating a first material through a first transparent wall of a first material tank and forming a first section of an nth layer of the part on a platform, positioning the platform with the first section of the nth layer in a second material tank with a distance between the first section of the nth layer and a second transparent wall, and irradiating a second material such that a second section of the nth layer of the part is formed on the platform adjacent to the first section of the nth layer. The method repeats forming first and second sections of additional layer until a predetermined number of total layers are formed. Positioning the first and second sections with a distance between the second and first transparent walls, respectively, inhibits crashing during forming of the part.