Preform Infrared Heating Zones for Uniform Bottle Thickness
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Solution Overview
Problem
Existing methods for manufacturing bottles from thermoplastic resins without strain hardening properties result in non-uniform thickness and weak mechanical properties due to materials like biodegradable or low-density plastics, which do not exhibit strain hardening.
Innovation Solution
A method using an array of infrared emitters with controlled power levels and settings for rotation and translation speeds to heat preforms with uneven thickness, focusing more heat on specific zones to reinforce and guide deformation during blow-moulding, ensuring homogeneous bottle thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If thermoplastic resins without strain hardening properties (e.g., biodegradable or low-density plastics) are used to manufacture bottles, then weight reduction is achieved (up to 30% compared to PET bottles), but the bottle thickness becomes non-uniform and mechanical properties become weak
Solution Approach 1:
The heating apparatus applies different heating intensities to different zones of the preform. Specifically, the equatorial zone receives higher heating intensity while the polar zones receive lower heating intensity, creating a non-uniform temperature distribution that compensates for the material's lack of strain hardening. This local quality approach ensures uniform bottle thickness by pre-conditioning specific regions before blow-moulding.
Solution Approach 2:
The invention changes the temperature parameter distribution across the preform by using multiple heating zones with different power levels. The equatorial zone is heated to a higher temperature while polar zones are heated to lower temperatures, modifying the thermal state of different preform regions to achieve uniform deformation during subsequent blow-moulding.
2Weight of moving object
If thermoplastic resins without strain hardening properties are used, then weight reduction is achieved, but mechanical strength of the bottle becomes weak
Solution Approach 1:
The heating apparatus creates different thermal conditions in different preform zones, with the equatorial zone receiving higher heating intensity. This local quality approach strengthens the material in critical regions through controlled thermal treatment, improving overall bottle mechanical strength while maintaining weight reduction benefits.
Solution Approach 2:
The preform undergoes preliminary heating treatment before blow-moulding, where specific zones are pre-heated to optimal temperatures. This preliminary action prepares the material in advance, ensuring it achieves the desired mechanical properties during the forming process without requiring the material to have inherent strain hardening characteristics.
3Ease of manufacture
If conventional heating methods are used on preforms made from materials without strain hardening, then manufacturing process remains simple, but the resulting bottle has non-uniform thickness
Solution Approach 1:
The heating apparatus is divided into multiple independent heating zones (equatorial zone and polar zones) that can be controlled separately. This segmentation allows each zone to receive customized heating intensity, enabling precise control over the temperature distribution in the preform to achieve uniform bottle thickness.
Solution Approach 2:
Different zones of the preform are subjected to different heating intensities - the equatorial zone receives higher intensity while polar zones receive lower intensity. This local quality approach addresses the specific deformation needs of each region, ensuring uniform thickness distribution in the final bottle product.
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 allows for the production of bottles with uniform thickness and improved mechanical properties from materials lacking strain hardening, such as polypropylene or polyethylene, achieving up to 30% weight reduction compared to PET bottles.
Implementation Method 1
an array of infrared emitters (50) arranged in multiple columns and multiple rows
Implementation Method 2
the heat generated by the infrared emitters is higher than the heat generated by the other subsets of columns
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2D
AI summary
Method for heating a preform (1) comprising: introducing the preform (1) into a heating apparatus (5) comprising an array of infrared emitters (50) arranged in multiple columns (Cj) and multiple rows (Ri), orienting angularly the preform at an input angular position by rotating the preform around the longitudinal axis; setting power levels of the infrared emitters (50) so as to divide the array of infrared emitters (50) into subsets of columns (SCn), each subset of columns (SCn) generating heat at a different power level from an adjacent subset of columns (SCn); and heating the preform (1) with the array of infrared emitters (50) while translating the preform (1) in a direction parallel to the rows (Ri) of the array at a translation speed, and simultaneously rotating said preform (1) around its longitudinal axis (Al) in front of said infrared emitters (50) at a rotation speed.