Injection Device Cone-Shaped Melting Holes Resin Quality
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Solution Overview
Problem
Existing injection devices in molding machines face inefficiencies in melting pellets due to their low thermal conductivity, leading to prolonged melting times, mechanical damage, and incomplete melting, especially with pellets containing glass fibers, resulting in poor work efficiency and quality of the molded resin.
Innovation Solution
The design incorporates a cylinder with a melting instrument featuring cone-shaped passages and a plunger that ensures uniform melting by maintaining a consistent temperature across the pellet's circumference, with a heating unit that maintains a high temperature state immediately before injection, preventing thermal and mechanical stress on the pellets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pellets are heated in a conventional cylinder with screw rotation, then the pellets are eventually melted, but the melting time is excessively long due to low thermal conductivity of resin
Solution Approach 1:
The cylinder is divided into multiple heating zones with independent heating elements along the axial direction, allowing simultaneous heating of multiple pellet sections. The screw is also segmented into heating sections with thermal conductors at different positions, enabling parallel heat transmission to multiple pellets, thereby dramatically reducing total melting time.
Solution Approach 2:
The heating elements and thermal conductors are pre-positioned and activated before pellet injection begins. The system pre-heats the cylinder and screw surfaces to optimal temperatures, so that when pellets contact these surfaces, immediate and efficient heat transfer occurs, eliminating the need for prolonged heating during the injection cycle.
2Manufacturing precision
If pellets are pressed onto the inner wall of the cylinder by screw rotation, then some melting occurs at the contact surface, but the interior of the pellet remains unmelted
Solution Approach 1:
Different regions of the screw are equipped with thermal conductors at different axial positions, creating localized heating zones that correspond to different sections of the pellets. This ensures that heat is applied to specific areas where needed, achieving uniform melting throughout the pellet structure rather than just at the contact surface.
Solution Approach 2:
Thermal conductors act as intermediary elements between the heating elements and the pellets. These conductors are in direct contact with the pellets and efficiently transmit heat from the heating zones to the pellet interiors, ensuring complete and uniform melting without requiring excessive pressure or time.
3Reliability
If excessive amounts of pellets are charged into the cylinder to ensure complete melting, then melting can be achieved, but the amount of resin required is dozens of times more than needed for one injection
Solution Approach 1:
The heating elements and thermal conductors are designed to automatically regulate heat distribution based on the actual pellet load and position. The system self-adjusts to melt only the necessary amount of resin completely, eliminating the need to overcharge the cylinder with excessive pellets just to ensure adequate melting of a smaller portion.
4Productivity
If the screw rotates to transfer and melt pellets, then pellets are moved to the injection side, but mechanical damage occurs particularly to pellets containing glass fibers
Solution Approach 1:
The conventional mechanical friction-based heating and transferring method is replaced with a thermal field-based system. Heating elements and thermal conductors provide the primary heating function, eliminating the need for aggressive mechanical friction between the screw and pellets. This substitution of mechanical action with thermal action prevents damage to glass fiber-reinforced pellets while maintaining efficient transfer and melting.
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
This solution enables rapid and uniform melting of pellets, reducing the injection time and improving work efficiency, ensuring high-quality resin molding with minimal material waste and resource usage.
Implementation Method 1
a heating unit heating the melting instrument, wherein the melting instrument is disposed between the plunger and the nozzle
Implementation Method 2
a melting instrument with a plurality of melting holes, which are cone-shaped passages, formed in a cylinder-shaped instrument body
Data Source
AI summary
A injection device in molding machine is capable of efficiently heating and melting a plurality of charged pellets in a short period of time, and injecting a melting resin with superior quality.The injection device has a cylinder including a pellet supply port, a plunger, a driving unit, a melting instrument with a plurality of melting holes, which are cone-shaped passages, formed in a cylinder-shaped instrument body to communicate from inflow-side large openings to outflow-side small openings, a nozzle provided on an injection side of the cylinder and a heating unit heating the melting instrument. A diameter of the tip-end of the plunger is set to be the same as a diameter of the outflow side face of the melting machine.