Compression Modulus Determination in Injection Molding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current injection molding processes inaccurately determine the compression behavior of materials due to neglecting the whole dead volume in the molding machine, leading to incorrect calculations of compression modulus and melt volume, which affects the precision of volume flow and pressure regulation.
Innovation Solution
A method that considers the entire dead volume of the molding machine during compression tests, allowing for the accurate determination of compression modulus and melt volume by conducting multiple tests under different conditions, and using these values to calculate realistic injection volumes and pressure dependencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If compression tests are conducted in a closed cylinder (prior art), then the test setup is simple and well-defined, but the dead volume of the gating system and distribution system is not considered, leading to inaccurate compression modulus determination
Solution Approach 1:
The invention extracts the material storage space from the closed cylinder configuration of prior art, leaving it unclosed to allow material to be introduced from the plasticizing unit. This extraction enables the gating system and distribution system to be included in the compression test, thereby capturing the entire dead volume for accurate compression modulus determination.
Solution Approach 2:
The invention makes the compression test system universal by integrating it with the injection molding machine's plasticizing unit and gating system. The same system can perform both normal injection molding operations and compression tests, eliminating the need for separate dedicated test equipment while achieving comprehensive dead volume measurement.
2Measurement precision
If the material storage space is closed during compression tests (prior art), then the volume calculation is straightforward, but the gating system and distribution system dead volume is excluded, resulting in incomplete compression behavior characterization
Solution Approach 1:
The invention uses feedback from the measured compression modulus and known dead volume to calculate the actual melt volume in the material storage space. By measuring pressure and screw position, the system determines compression behavior and uses this feedback to accurately calculate melt volume, accounting for the entire dead volume including gating and distribution systems.
Solution Approach 2:
The invention performs preliminary determination of the compression modulus and dead volume through compression tests before conducting actual injection molding operations. This preliminary characterization enables accurate melt volume calculation and injection parameter optimization in subsequent production cycles.
3Manufacturing precision
If only the screw vestibule dead volume is considered (prior art), then the calculation is simple, but the gating system dead volume is neglected, leading to incorrect melt volume and volume flow calculations
Solution Approach 1:
The invention segments the total dead volume into distinct components: screw vestibule dead volume and gating system dead volume (including distribution system). By measuring and characterizing each segment separately through compression tests, the system achieves accurate total dead volume determination while maintaining clear understanding of individual contributions.
Solution Approach 2:
The invention changes the parameter measurement approach from direct geometric calculation to experimental determination through compression tests. By measuring pressure-volume relationships and determining compression modulus experimentally, the system accurately captures the functional dead volume including all elastic and plastic deformation effects in the gating and distribution 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
This approach enables precise calculation of realistic injection volumes, decompression lifts, dwell times, and material characteristics, improving the control and regulation of the injection molding process by accounting for all dead volumes and pressure dependencies.
Implementation Method 1
the compression modulus K of a material describes which all-sided pressure modification is necessary in order to cause a determined modification of the volume of the material
Implementation Method 2
The material prepared in a material storage space is introduced in a mold cavity
Data Source
AI summary
In a method for determining at least one parameter for the description of the compression behavior of a material processed in a molding machine, at least a part of the processed material is introduced into a mold cavity via a distribution system and a gate, and the processed material solidifies in the mold cavity. A compression test is performed in which a volume storing the material is modified and a measurement of the resulting pressure modification is conducted or a pressure applied onto the material is modified and a measurement of the resulting modification of the volume is conducted. A parameter for the description of the compression behavior is calculated based on the result of the compression test by using a mathematical model. The compression test is conducted when the gate is at least substantially solidified or when the hot runner is closed.