Flat Screw Plasticizing Device Bridge Phenomenon Control
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Solution Overview
Problem
Existing three-dimensional modeling and injection molding devices face issues with material plasticization, specifically the 'bridge phenomenon' where the outer end of the spiral groove clogs, leading to incomplete plasticization and difficulties in restarting the device after shutdown, due to residual material remaining in a solid state.
Innovation Solution
A plasticizing device with a flat screw, barrel, heater, cooler, and controller that controls the rotation, heating, and cooling to prevent the bridge phenomenon by ensuring the outer circumference of the flat screw remains at a temperature no higher than during plasticization upon restarting, using a predetermined time to allow the cooler to manage temperature and prevent material from being plasticized at the outer circumference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater is activated to plasticize material in the outer circumferential portion of the rotor, then the material can be plasticized, but the outer end portion of the spiral groove clogs and the bridge phenomenon occurs
Solution Approach 1:
The patent applies local quality by creating different temperature zones within the rotor: the outer circumferential portion is cooled to prevent premature plasticization, while the inner portion near the center is heated to enable material plasticization. This spatial differentiation of temperature conditions prevents the bridge phenomenon by ensuring material remains solid at the outer end of the spiral groove while being plasticized near the center.
2Productivity
If the plasticizing delivery device is stopped and restarted, then production can resume, but the residual solid material causes the bridge phenomenon and prevents smooth startup
Solution Approach 1:
The patent applies preliminary action by pre-cooling the outer circumferential portion of the rotor before material is fed into the spiral groove during startup. This preparatory cooling action ensures that when material is introduced, it remains solid in the outer regions and only plasticizes in the heated inner regions, preventing the bridge phenomenon during startup without requiring extensive heating time.
3Ease of operation
If the outer end portion of the spiral groove is used for material supply, then fresh material can be fed, but premature plasticization causes clogging and loss of conveying power
Solution Approach 1:
The patent maintains conveying power by applying local quality through differential temperature control: the outer end portion of the spiral groove is cooled to keep material solid, preserving its flowability and preventing clogging, while the inner portion is heated to enable plasticization. This spatial temperature differentiation ensures both continuous material feeding and sufficient conveying power throughout the spiral groove.
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
Prevents the bridge phenomenon, allowing for smooth startup and reducing the load on the drive motor by controlling the temperature and rotational speed, ensuring high-quality shaping of three-dimensional articles.
Implementation Method 1
a heater configured to heat a material fed between the flat screw and the barrel
Implementation Method 2
a cooler configured to cool an outer circumference of the flat screw
Data Source
AI summary
A plasticizing device includes a drive motor, a flat screw, a barrel, a heater, a cooler, and a controller, wherein the controller executes a plasticizing step of controlling the drive motor, the heater, and the cooler to plasticize a material fed between the flat screw and the barrel to make the material plasticized outflow from a communication hole, a stopping step of stopping at least the drive motor and the heater after executing the plasticizing step to stop the plasticizing step, and a start-up step of starting up the heater and controlling at least one of the heater and the cooler so that the outer circumference of the flat screw becomes at a temperature no higher than in the plasticizing step when resuming the plasticizing step after a predetermined time elapses from the stopping step.