Vacuum Compression Moulding Apparatus for Homogeneous Thermoplastic Samples
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Solution Overview
Problem
Current methods for molding thermoplastic materials into homogenous sample bodies face challenges such as air pocket trapping, slow processing times, and high costs, particularly in achieving consistent results without bubbles and maintaining sample integrity.
Innovation Solution
An apparatus comprising a main body with a hollow bore, a separation foil, a piston, and a vacuum connector allows for the heating and compression of thermoplastic material under vacuum, ensuring a homogenous sample body is formed efficiently and cost-effectively, with the ability to easily remove the sample without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sample is melted under atmospheric conditions and air bubbles are allowed to escape, then air pockets can be removed from the sample, but the processing time becomes excessively long due to high viscosity
Solution Approach 1:
The patent applies vacuum conditions (inert environment) during the melting process to prevent air from being trapped in the sample material. By evacuating the chamber before and during melting, air bubbles are removed from the atmosphere, allowing the material to melt and consolidate without incorporating air pockets, thereby achieving homogeneous samples in shorter time without excessive heating
2Manufacturing precision
If the sample is melted in a vacuum to prevent air bubbles, then homogenous samples can be produced, but expensive specialized equipment is required
Solution Approach 1:
The patent designs a mold that can be used for both compression molding and vacuum melting processes. The same mold structure serves multiple functions: it can be used under atmospheric conditions for compression molding and under vacuum conditions for melting, eliminating the need for separate specialized equipment for each process
3Manufacturing precision
If a vacuum platen press is used to produce samples under vacuum, then air pockets can be prevented, but the large sample chamber volume causes slow response to temperature and pressure changes
Solution Approach 1:
The patent employs a nested structure where the sample cavity is positioned within the mold, and the mold itself is positioned within the vacuum chamber. This nested arrangement allows the vacuum to be applied directly to the sample cavity through the mold structure, creating a compact effective vacuum volume that responds quickly to pressure changes while maintaining the ability to produce homogeneous samples
4Shape
If the sample chamber volume is fixed by the mold, then well-defined shaping can be achieved, but volume contraction during melting causes shrinking cavities within the sample
Solution Approach 1:
The patent uses a flexible diaphragm that can dynamically adjust its position and shape during the melting process. As the material melts and contracts, the diaphragm moves to accommodate the volume change, preventing the formation of shrinking cavities while maintaining the external shape definition provided by the mold
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 apparatus enables rapid production of homogenous thermoplastic samples with minimal thermal stress, utilizing inexpensive standard laboratory equipment, and effectively prevents air bubbles, making it suitable for expensive substances like active pharmaceutical ingredients.
Implementation Method 1
a vacuum connector (140) adapted to be connected to a vacuum source
Implementation Method 2
wherein the base plate is adapted to transfer heat to and from a thermoplastic material resting on the protrusion
Implementation Method 3
the piston applies a compressing force to the thermoplastic material resting on the protrusion
Data Source
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AI summary
There is provided an apparatus for molding a thermoplastic material into a homogenous sample body having a predetermined shape, the apparatus comprising: (a) a main body (110) comprising a first opening (112), a second opening and a hollow bore (116) connecting the first opening (112) with the second opening, the hollow bore (116) being adapted to receive a separation foil shaped to cover at least a part of the hollow bore surface; (b) a piston (120) adapted to fit moveably into the hollow bore (116) containing the separation foil; (c) a base plate (130) comprising a protrusion, wherein the base plate (130) is adapted to be inserted into the first opening (112) in such a manner that the protrusion extends into a part of the hollow bore (116) containing the separation foil, and wherein the base plate (130) is adapted to transfer heat from a heating unit to a thermoplastic material (150) resting on the protrusion (132); (d) a vacuum connector (142) adapted to be connected to a vacuum source; (e) a lid (140) adapted to fit moveably into the second opening and adapted to apply a force to the piston (120) when the vacuum connector (142) is connected to the vacuum source such that the piston (120) applies a compressing force to the thermoplastic material (150) resting on the protrusion. There are further provided a method and a system for molding a thermoplastic material into a homogenous sample body having a predetermined shape.