Filament Drying Tube With Heated Air for Moisture Control
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Solution Overview
Problem
Hygroscopic filaments used in additive manufacturing are prone to moisture absorption, leading to issues such as bubbling, warping, and chemical degradation, which can cause process failures and affect the quality of the printed objects.
Innovation Solution
A filament drying system with a closed-loop air recycling system and heating elements is used to condition the filament to a desired moisture content by heating only the portion of the filament needed for extrusion, utilizing a first heater for air pre-heating and a second heater along the tubing section to maintain and enhance drying efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the filament is dried by heating the whole reel for extended periods (4-24 hours), then the moisture content is reduced, but the material degrades and printing quality worsens
Solution Approach 1:
The drying system segments the filament treatment by focusing heat only on the portion of filament currently being fed through the drying zone, rather than heating the entire reel. This is achieved by positioning the heating element in the filament feed path, creating a localized drying environment that processes filament incrementally as it passes through.
Solution Approach 2:
The system performs preliminary drying action on the filament before it reaches the extrusion zone. The filament is dried in advance during its passage through the heated drying section, so that by the time it reaches the liquefier, it has already been conditioned to acceptable moisture levels without requiring prolonged overall drying cycles.
2Quantity of substance
If the filament is dried using a desiccant in controlled environment, then moisture is removed, but the process requires long time (4-24 hours) and repeated cycles degrade the material
Solution Approach 1:
The drying system operates continuously as filament passes through the drying zone during normal feeding operations. The heating element maintains continuous drying action on the filament surface and interior as it moves through, eliminating the need for separate, time-consuming drying cycles before printing.
Solution Approach 2:
The system introduces heated air as an intermediary medium to transfer moisture from the filament to the surrounding environment. The heating element warms the air, which then contacts the filament surface and penetrates inward, facilitating continuous moisture removal without requiring direct contact with desiccants or vacuum conditions.
3Object-affected harmful factors
If the filament is over-dried to remove all moisture, then bubbling and warping are prevented, but the material properties deteriorate and printing fails
Solution Approach 1:
The system applies partial drying action by removing only the excess moisture that causes defects, rather than attempting to remove all moisture from the filament. The heating temperature and exposure time are controlled to achieve sufficient drying for defect prevention while preserving the material's inherent properties and avoiding over-drying damage.
Solution Approach 2:
The system incorporates monitoring to detect when the filament has reached acceptable moisture levels and adjusts or stops the heating action accordingly. This feedback mechanism prevents continued heating that would lead to over-drying, ensuring material properties are maintained while still preventing bubbling and warping defects.
4Quantity of substance
If the filament is stored in humidity controlled environment (drybox), then water absorption is prevented, but the filament is exposed to uncontrolled environment during loading/unloading
Solution Approach 1:
The system performs preliminary drying of the filament in the drying zone before it is loaded into the printing system. This preliminary action ensures the filament is already at acceptable moisture levels when handling and loading occurs, compensating for the brief exposure to uncontrolled environment during these operations.
Solution Approach 2:
The drying system is integrated into the filament feed path, allowing the filament to dry itself during normal feeding operations without requiring separate storage infrastructure like dryboxes. The filament passes through the heated drying zone as part of its normal path to the extruder, providing self-service drying that eliminates the need for additional controlled storage environments.
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 system effectively reduces moisture content in the filament quickly and efficiently, preventing process failures and ensuring consistent print quality without subjecting the filament to excessive heating cycles, and can be retrofitted to existing 3D printers or integrated into production lines.
Implementation Method 1
a first heater arranged to heat air; a tubing section having a wall defining an enclosed passage, the passage arranged to convey a filament, the tubing section having an air inlet for providing heated air from the first heater into the passage
Implementation Method 2
a second heater arranged along at least part of the tubing section, in order to further heat filament within the passage
Implementation Method 3
the system effectively reduces moisture content in filaments, preventing issues like bubbling and warping
Data Source
AI summary
A system (27) arranged to dry a filament (5) used in additive manufacture, the system (27) comprising: a first heater (55) arranged to heat air; a tubing section (29) having a wall (31) defining an enclosed passage (33), the passage (33) arranged to convey a filament (5), the tubing section (29) having an air inlet (51) for providing heated air from the first heater (55) into the passage (33); and a second heater (59) arranged around along at least part of the tubing section (29), in order to further heat filament (5) within the passage (33).