Pelletizing Die Thermal Layout to Prevent Nozzle Resin Clogging
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Solution Overview
Problem
The solidification (clogging) of molten thermoplastic resin occurs when it passes through the nozzle holes in the die during pellet manufacturing, leading to inconsistent pellet sizes and operational inefficiencies.
Innovation Solution
A die design incorporating a first metallic member with internal nozzles of varying diameters, heat insulating layers, and strategically positioned heat sources to maintain optimal resin viscosity and prevent clogging, combined with a manufacturing method using a 3-D printer for precise construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat insulating layers are added inside the die member, then resin solidification is prevented and pellet quality improves, but device complexity increases
Solution Approach 1:
The heat insulating layers are nested inside the die member, with multiple layers arranged in a compact configuration within the limited space of the die body. The layers are positioned between the nozzle holes and the outer wall, creating a nested structure that provides insulation without significantly increasing the overall die dimensions or complexity.
Solution Approach 2:
The heat insulating layers are strategically positioned only in regions where temperature control is critical - specifically between the nozzle holes and the outer wall of the die member. This localized insulation approach prevents resin solidification at the nozzle openings while avoiding unnecessary complexity in regions where insulation is not required.
2Temperature
If multiple heat insulating layers are arranged inside the die, then temperature control improves, but manufacturing difficulty increases
Solution Approach 1:
The heat insulating layers are pre-formed as separate components with specific shapes and dimensions before being assembled into the die member. This preliminary preparation allows for precise control of layer thickness and positioning, ensuring uniform temperature distribution while simplifying the final assembly process through modular construction.
Solution Approach 2:
The thermal conductivity parameters of the heat insulating layers are carefully selected and varied to achieve optimal temperature distribution within the die. By changing the material parameters and layer thicknesses, the design achieves uniform heating without requiring complex multi-layer configurations that would difficult to manufacture.
3Manufacturing precision
If nozzle holes are positioned closer to the outer wall, then pellet size control improves, but resin clogging risk increases
Solution Approach 1:
Heat insulating layers are introduced as intermediary elements between the nozzle holes and the outer wall of the die member. These layers act as a thermal barrier that prevents heat loss from the nozzle region to the cooler outer wall, thereby maintaining resin temperature and preventing solidification and clogging while allowing the nozzles to be positioned optimally for pellet size control.
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 die design enhances pellet quality by maintaining consistent pellet sizes and preventing clogging, improving the performance of the extrusion process and the extruder.
Implementation Method 1
a plurality of first heat insulating layers 111 having a lower thermal conductivity than a thermal conductivity of the first metallic material are arranged inside the first member 110
Implementation Method 2
a first heat source 120 arranged inside the first member 110 not to overlap the first nozzle 131 and the second nozzle 132 in a plan view viewed from the extrusion surface 102
Data Source
AI summary
A performance of a die is improved. An injection hole IH, a nozzle NZa and a nozzle NZb are formed in a center member DIa of a die DI to extend from an extrusion surface ES to an injection surface IS. A heat source HT and a plurality of heat insulating layers HI1 are arranged inside the center member DIa. One of the plurality of heat insulating layers HI1 is adjacent to the nozzle Nzb and is closer to the extrusion surface ES than the heat source HT. The other of the plurality of heat insulating layers HI1 extends in a direction from the extrusion surface ES toward the injection surface IS at a position being farther from the nozzle NZb than the heat source HT.