Rotary Piston Extruder Head for 3D Printing
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Solution Overview
Problem
Existing 3D printing extruder technologies are limited by the speed of material extrusion and the types of materials used, primarily restricted to thermoplastics and composites in strand form, with challenges in controlling volume and complexity in handling larger volumes or diverse materials like metals and alloys.
Innovation Solution
A rotary piston extruder head with a loading and working chamber of epitrochoid profile, equipped with a heating system and heat sensor, allows for the use of bulk materials, pastes, and metals by utilizing a planetary motion mechanism to manage pressure and temperature, enabling the extrusion of a wide range of materials through a removable and replaceable working chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a screw type positive displacement pump is used to extrude molten material, then the material can be moved along the screw axis and extruded through a nozzle, but the structure becomes complex and material selection is limited to thermoplastics in strand form
Solution Approach 1:
The patent changes the fundamental operating parameters of the extruder by switching from a screw-type positive displacement pump to a rotary piston mechanism. This allows the system to handle materials with vastly different viscosities and flow characteristics, including metals, ceramics, and pastes, rather than being limited to thermoplastics. The rotary piston's reciprocating motion creates variable pressure zones that can accommodate both low-viscosity melts and high-viscosity pastes without requiring complex structural modifications.
Solution Approach 2:
The extruder is divided into distinct functional zones: a loading chamber for material input, a working chamber with the rotary piston for pressure generation and material transfer, and an extrusion zone at the nozzle. This segmentation allows each component to be optimized for its specific function, simplifying the overall structure while expanding material compatibility. The working chamber's epitrochoid profile specifically facilitates smooth material transition from loading to extrusion.
2Productivity
If pressure is applied to the whole mass in a syringe type extruder to control extrusion volume, then liquid and paste-like materials can be extruded, but the extruder becomes more cumbersome and startup/stopping time increases with larger volumes
Solution Approach 1:
The rotary piston extruder utilizes periodic reciprocating motion to generate pressure pulses that drive material extrusion. The piston moves back and forth in a controlled cycle, creating alternating pressure zones that efficiently push material through the nozzle. This periodic action allows for rapid start-stop capability since the piston can quickly reverse direction without requiring gradual pressure buildup, thereby reducing startup and stopping time while maintaining high extrusion speeds.
Solution Approach 2:
The system employs dynamic pressure control through the moving rotary piston rather than static pressure application. The piston's position and speed can be dynamically adjusted during operation, allowing the extruder to rapidly respond to changing requirements. This dynamic mechanism enables fast acceleration and deceleration of the extrusion process, significantly reducing the time needed to start and stop extrusion compared to syringe-type systems that require gradual pressure changes.
3Productivity
If thermoplastics in strand form are used as work material, then the extrusion process is simple, but the speed of material extrusion is limited and material options are restricted
Solution Approach 1:
The rotary piston extruder is designed as a universal system capable of processing multiple material types including thermoplastics, metals, ceramics, and paste-like materials. The working chamber's epitrochoid profile and the piston's reciprocating motion create a flexible pressure environment that can accommodate materials with different rheological properties. This multi-functionality allows the same extruder mechanism to handle both low-viscosity thermoplastic melts and high-viscosity metal pastes without requiring structural changes, thereby increasing extrusion speed while expanding material options.
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
This solution broadens the range of materials that can be used in 3D printing, including metals and alloys, by enhancing the extrusion process with controlled pressure and temperature, improving printing efficiency and versatility.
Implementation Method 1
a loading chamber 2 and a working chamber 3 of a special profile in the form of an epitrochoid with a rotor (piston) 4 moving therein are located within a single housing 1. An eccentric shaft 5 with a sliding cone fit is located at the centre of the working chamber, with a rotor mounted on its eccentric
Implementation Method 2
At least one heating element and a heat sensor are disposed within the housing
Implementation Method 3
A three-sided rotor (piston) of a triangular shape having arc-shaped sides and a central fitment hole on one of butt ends of which an internal gear is located
Data Source
AI summary
The invention relates to the field of 3D printing, particularly to the extrusion method (Material Extrusion), i.e., the layer-by-layer deposition of a molten building material through an extruder head (an extruder). The present device allows for using a wide range of materials when printing, such as liquids, pastes, and melts (including metals), as well as for using pre-treated secondary raw materials. An extruder has, within a single housing, a loading chamber and a removable working chamber having a three-sided rotor (piston) moving therein and an eccentric drive shaft, as well as an extruder tip connected to the housing, said tip having a removable nozzle on its end, a built-in heat sensor, and a built-in heating element. At least one heating element and heat sensor are disposed within the housing. The extruder is disposed on a mounting frame having a drive motor, and said frame fastens to a moving platform of a 3D printer.