High Speed FDM 3D Printer Closed Loop Motion System
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Solution Overview
Problem
Conventional FDM 3D printers face issues such as filament slippage, hot end jamming, and print failure when operating at high speeds due to backpressure, insufficient heat supply, and inadequate melting time.
Innovation Solution
The implementation of a high-flow-rate hot end with a large melt zone, optimized heat output, and a closed loop brushless motor control system for the motion system, along with a high-flow-rate extruder that distributes load over a larger section of filament to prevent slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional hobbed pulley extruder is used to force filament through the hot end, then the system can operate at low speeds, but at high speeds the backpressure causes the hobbed pulley to slip against the filament, cut a groove into the filament, or cause the stepper motor to lose steps
Solution Approach 1:
The patent replaces the mechanical hobbed pulley system with a toothed belt and pulley system. The toothed belt engages with the pulley teeth to provide positive displacement, eliminating slippage between the extruder and filament. This mechanical substitution allows reliable high-speed filament feeding without the backpressure issues that plague hobbed pulley systems.
Solution Approach 2:
The patent introduces a PTFE (Teflon) tube as an intermediary component between the extruder and hot end. This tube acts as a low-friction guide that reduces resistance to filament movement, allowing the toothed belt system to efficiently transmit force to the filament without causing slippage or filament damage at high speeds.
2Productivity
If a conventional hot end is used at high print speeds, then the volume of filament being forced through the hot end absorbs more heat than the hot end can supply, causing the hot end to cool down
Solution Approach 1:
The patent implements a heated PTFE tube section upstream of the hot end that pre-heats the filament before it enters the main hot end. This preliminary heating action reduces the thermal load on the hot end, allowing it to maintain temperature even at high volumetric flow rates where the filament would otherwise absorb more heat than the hot end can supply.
Solution Approach 2:
The heating system is segmented into multiple zones: a heated PTFE tube section for pre-heating and a separate hot end for final melting. This segmentation allows each component to be optimized for its specific function, with the pre-heater handling the bulk of the thermal load and the hot end focusing on precise melting and extrusion.
3Speed
If a conventional hot end is used at high print speeds, then the time that the filament spends in contact with the hot end is not sufficient for the filament to completely melt
Solution Approach 1:
The heated PTFE tube performs preliminary melting of the filament before it reaches the hot end. This pre-melting action reduces the time required in the hot end, allowing sufficient melting to occur even at high print speeds where the filament transit time is reduced.
Solution Approach 2:
The patent extends the melting zone by adding length to the heated PTFE tube section. This dimensional extension provides additional time and space for filament melting to occur upstream, effectively increasing the total melting time without compromising print speed.
4Device complexity
If an open loop control system is used to drive stepper motors, then the system is simpler, but rapid accelerations in direction cause the stepper motors to lose steps and the printer cannot self correct
Solution Approach 1:
The patent implements a closed-loop control system using encoders that provide real-time feedback on the actual position of the motors and carriage. This feedback allows the control system to detect and correct step losses, ensuring accurate positioning even during rapid accelerations and direction changes, while eliminating the reliability problems of open-loop systems.
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 reliable high-speed 3D printing with improved filament feeding and melting, reducing the likelihood of print failures and maintaining high precision and speed.
Implementation Method 1
The high-flow-rate hot end comprises a heat sink, a heater system and a large bore nozzle. The filament from the extruder moves through the filament tube to the high-flow-rate hot end for printing from the large bore nozzle.
Implementation Method 2
The time that the filament spends in contact with a conventional hot end is not sufficient for the filament to completely melt. This causes the hot end to jam, which also causes a print failure.
Implementation Method 3
The x-carriage is positioned on the XY-gantry. Each of the plurality of brushless motors of the XY gantry is controlled by the plurality of brushless motors controllers using field oriented control for closed loop positioning
Implementation Method 4
Each of the plurality of brushless motors of the XY gantry is controlled by the plurality of brushless motors controllers using field oriented control for closed loop positioning to achieve high speeds with high precision using the plurality of encoders to track the location of the x-carriage.
Data Source
AI summary
The present invention and its variations provide a method of Fused Deposition Modeling (FDM) 3D Printing at a high rate of speed, much higher than that of a conventional 3d printer (e.g. 5 meters per second travel, depositing 3 cubic centimeters of material per second). The invention uses a closed loop brushless motor control system to rapidly move a carriage to a precise position. This carriage contains on itself a high-flow-rate hot end, which is a device which can liquify material at a high flow rate, which in turn is used to deposit material onto a heated bed. The printer contains a high-flow-rate extruder, which is a device designed to maximize the friction between a belt and a pulley in order to drive a large amount of material filament through the high-flow-rate hot end onto a bed without slipping.