Filament Changing System for 3D Printing Extruders
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Solution Overview
Problem
Current filament changing systems for 3D printing using FLM (Fused Layer Modeling) face challenges such as interruptions in the printing process, risk of clogging, high construction effort, and inability to seamlessly switch between different materials and colors due to complex extruder arrangements and welding requirements.
Innovation Solution
A filament changing system with a selection device and separating unit arranged between the storage and extruder, allowing for seamless transition by conveying the new filament at a higher speed to catch up with the previous one, eliminating the need for welding or mechanical coupling, and utilizing a single extruder with adjustable drive units for each filament.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple feed devices with separate extruder drives are used for each filament, then filament changing capability is improved, but device complexity and construction effort increase significantly
Solution Approach 1:
The patent merges multiple filament feeding functions into a single extruder by implementing a common feed device that can handle multiple filaments simultaneously. The extruder is designed with a single drive mechanism that processes all filaments through one heating zone and die, eliminating the need for multiple separate extruder assemblies while maintaining the ability to switch between different filament types.
Solution Approach 2:
The single extruder is designed as a universal device capable of processing different filament materials and diameters. The feed device can accommodate multiple filaments of varying properties, and the heating zone can adjust its temperature profile to suit different materials, making one extruder perform the function of multiple specialized extruders.
2Ease of operation
If filament retraction is performed before changing to the next filament, then the next filament can be fed properly, but the printing process is interrupted and already plasticized material may clog the guide elements
Solution Approach 1:
The patent enables continuous filament feeding during material transitions by eliminating the retraction step. The single feed device maintains constant forward motion of the filament through the heating zone, allowing one filament to be replaced by another without stopping the extrusion process. The heated material flows continuously through the die, preventing clogging while enabling seamless material changes.
3Reliability
If filaments are welded together to enable material switching, then filament continuity is achieved, but clean welding is only possible with identical materials and welding creates geometric inhomogeneities that can cause jamming or clogging
Solution Approach 1:
The patent extracts the welding operation entirely from the filament changing process. Instead of joining filaments through welding, the system uses a single continuous feed device that pushes filaments sequentially through the heating zone. The transition from one material to another occurs naturally at the die outlet where the extruded material forms a clean transition point without requiring any joining operation, thus eliminating welding-related problems.
4Adaptability or versatility
If stick filament connection method is used to eliminate welding, then different materials can be joined, but creating a new connection for each change is extremely time-consuming
Solution Approach 1:
The patent prepares multiple filaments in advance within the single feed device, positioning them ready for immediate insertion into the heating zone. The feed device maintains a continuous feeding action, so when material switching is required, the next filament is already in position and can be fed forward without any connection or setup time, eliminating the time-consuming connection process inherent in stick filament methods.
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 uninterrupted and automated filament changes during the printing process, allowing for the use of various materials and colors without interruptions, reducing material waste, and simplifying the system design with fewer conveyor drives, thus improving process reliability and efficiency.
Implementation Method 1
the newly used filament is conveyed behind the previously used filament at a higher conveying speed than the conveying speed of the previously used filament
Implementation Method 2
a wire-like starting material on a spool is plasticized using an extruder
Implementation Method 3
the printing materials are pulled from several filament spools and fed to a Y-shaped mixer located close to the heating element
Data Source
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AI summary
The invention relates to a filament changing system (1) and a method for changing filaments (20) of different color and/or different material for the production of 3D printed parts according to the FLM process, in which at least one selection device (6) for selecting the filament (20) to be used and at least one cutting unit (9) for separating the previously used filament (20) are arranged between a storage device (4) for all used filament strands (20) and an extruder (3), and in which each of the usable filaments (20) is assigned a switching device (15) which can selectively bring the associated filament (15) into the conveying position for conveying by a drive unit (14) at a defined speed or release it so that the filament (20) can be conveyed unhindered, preferably by means of the extruder (3), wherein the selection device (6) has an assignment device (38, 32),which forms a section of the conveying path from the storage device (4) to the extruder (3) for the filament (20) used in each case, and the switching device (15) and drive unit (14) are adjustable, at least temporarily, so that the newly used filament (20) is conveyed behind the previously used filament (20) at a higher conveying speed than the conveying speed of the previously used filament (20).