Polymer Compression Moulding With Laser Dose Heating
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Solution Overview
Problem
Compression moulding of polymeric materials results in uneven cooling and premature solidification of polymeric material, leading to aesthetic and optical defects, such as visible spots and cold sealing zones, which can cause breakage during processing and use.
Innovation Solution
A thermal conditioning device is used to uniformly heat the surface portions of the polymeric material before moulding, ensuring homogeneous temperature distribution and preventing premature solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the polymeric material is conveyed and cut during compression moulding, then the dose can be separated and positioned in the mould, but the material cools prematurely causing visible spots and aesthetic defects
Solution Approach 1:
The patent applies preliminary action by heating the polymeric material dose with a laser beam before the dose is inserted into the mould. This pre-heating action compensates for the temperature loss that occurs during cutting and conveying, ensuring the material maintains adequate temperature for uniform moulding without causing the aesthetic defects associated with premature cooling
2Productivity
If the cutting edge separates the dose from the continuous extrudate, then the dose can be conveyed to the mould, but the edges cool rapidly and solidify creating non-uniform polymeric material behavior
Solution Approach 1:
The patent applies parameter changes by using a laser beam to alter the temperature parameter of the polymeric material dose. The laser heating changes the thermal state of the material, particularly at the edges that cooled during cutting, restoring uniform viscosity and preventing premature solidification that would cause non-uniform behavior during compression moulding
3Manufacturing precision
If the thermal conditioning device heats the surface portions of the polymeric material, then homogeneous temperature distribution is achieved, but additional equipment and process steps are required
Solution Approach 1:
The patent applies mechanics substitution by replacing what would traditionally be a mechanical thermal conditioning device with a laser beam system. The laser provides non-contact heating, eliminating the need for physical heating elements that would complicate the apparatus structure, while still achieving homogeneous temperature distribution in the polymeric material dose
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 solution prevents the formation of visible spots and cold sealing zones, resulting in high-quality, defect-free objects with improved homogeneity and reduced breakage risk.
Implementation Method 1
a laser beam suitable for heating a surface portion of the dose
Data Source
AI summary
An apparatus for forming an object comprises an extruding device (2) for supplying a continuous extrudate of polymeric material, at least one separating element for cutting the continuous extrudate thereby separating a dose (6; 106) of polymeric material from the continuous extrudate, at least one mould (5; 105; 205; 305; 405) comprising a first mould part (9; 109; 209; 309) and a second mould part (8; 108; 508) which are movable relative to one another between an open position, in which the dose (6; 106) is rested on a receiving part selected from the first mould part (9; 109; 209; 309) and the second mould part (8; 108; 508), and a closed position, in which a forming chamber is defined between the first mould part (9; 109; 209; 309) and the second mould part (8; 108; 508), the forming chamber having a shape corresponding to said object. The apparatus further comprises a thermal conditioning device (11; 111; 211; 311; 411) configured to act on the dose (6; 106) while the dose (6; 106) is positioned in said at least one mould (5; 105; 205; 305; 405) and before the closed position is reached, by thermally conditioning at least one surface portion (20; 120) of the dose (6; 106) which is distinct from a resting portion (17; 117) of the dose (6; 106) which is resting on the receiving part.