Additive Manufacturing Printhead With Automated Nozzle Exchange Sealing
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Solution Overview
Problem
Existing additive manufacturing systems face challenges with nozzle wear, leakage due to thermal expansion mismatch, and the need for frequent cleaning or component exchange, leading to process downtime and increased costs.
Innovation Solution
A printhead system with a detachable nozzle plate and crucible changer, utilizing a plastically deformable seal and actuators for automated nozzle and crucible exchange during the manufacturing process, allowing for continuous operation without cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a friction-fit clamping nut is used to fasten the nozzle plate to the crucible, then the nozzle plate can be exchanged during the process, but leakage of the liquid melt occurs due to thermal expansion mismatch between metallic clamping nut and ceramic crucible
Solution Approach 1:
The sealing ring is designed to change its physical state from a softer state during mounting to a hardened state during operation. The thermoplastic material is heated above its melting point during the mounting process to become soft and deformable, allowing it to seal effectively. During the additive manufacturing process, the sealing ring is maintained at a temperature above its glass transition temperature but below its melting point, keeping it in a hardened state that resists deformation and maintains sealing reliability under thermal expansion mismatch conditions.
Solution Approach 2:
The sealing ring is made from a composite material system combining a thermoplastic polymer matrix with reinforcing fibers or fillers. This composite structure provides both the thermal resistance needed for high-temperature operation and the controlled deformability required for effective sealing. The composite material exhibits different mechanical properties at different temperatures, being soft and deformable at mounting temperature but rigid and stable at operating temperature.
2Productivity
If the nozzle plate is exchanged during the printing process, then process downtime is reduced, but the sealing reliability deteriorates due to thermal expansion differences between metallic components and ceramic parts
Solution Approach 1:
The sealing ring utilizes temperature-dependent parameter changes to adapt to different operational states. During quick exchange operations, the sealing ring is heated to become soft and conformable, allowing reliable sealing despite thermal expansion differences. During continuous manufacturing, the sealing ring is maintained in a hardened state that provides stable sealing performance under the thermal and pressure conditions of the additive manufacturing process.
Solution Approach 2:
The sealing system transitions from a static seal to a dynamic seal that adapts its properties based on operational requirements. The thermoplastic sealing ring can be rapidly heated and cooled to change its mechanical properties, allowing it to be soft during mounting/exchange and hard during operation. This dynamic property change enables the seal to maintain reliability across different operational phases.
3Force
If a metallic clamping nut is used for fastening, then the fastening force is sufficient, but thermal expansion mismatch with ceramic components causes sealing failures
Solution Approach 1:
The sealing ring is constructed from a composite material that combines the high-temperature resistance of ceramic fillers or fibers with the deformability of a thermoplastic matrix. This composite structure provides both the mechanical strength needed to withstand fastening forces and the thermal resistance required to maintain sealing integrity under thermal expansion mismatch conditions between metallic and ceramic components.
Solution Approach 2:
The sealing ring's material parameters are dynamically controlled through temperature management. During assembly, the sealing ring is heated to reduce its viscosity and increase deformability, allowing it to conform to the mating surfaces under fastening force. During operation, the sealing ring is maintained at a temperature that keeps it in a hardened state, providing stable dimensional properties and reliable sealing despite thermal expansion differences between the metallic clamping nut and ceramic crucible.
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 efficient and continuous manufacturing by reducing downtime, minimizing leakage, and facilitating the use of different materials, thereby enhancing production efficiency and droplet quality.
Implementation Method 1
an elastic portion of a component is provided so that a sufficient fastening force of, for example, the clamping nut to the ceramic guide sleeve can be obtained. Furthermore, it has been recognized in particular that a plastic deformation of a heat-resistant sealing ring can prevent leakage of the melt at the nozzle plate.
Implementation Method 2
At least one actuator is configured to be controlled by the controller to move the printhead and/or the magazine relative to each other so that one of the multiple nozzles is moved to the first mounting position.
Implementation Method 3
it is advantageous if the metallic material of the component has substantially the same coefficient of thermal expansion as the ceramic component
Data Source
AI summary
An apparatus (100) for additive manufacturing of a component facilitates an exchange of components that are subject to wear and/or of components that facilitate usage of different materials in an additive manufacturing process. For this purpose, the apparatus includes a magazine (112) that has multiple nozzles (110) and facilitates an automated exchange of one nozzle with another during a manufacturing process. By using suitable actuators, either only the nozzle (110) can thus be exchanged, or the reservoir (108) containing the liquid material having the nozzle (110) attached to it can be replaced. When changing the reservoir (108), a piston (130) received therein can be exchanged at the same time.