Resin Preform Cooling via Segmented Air Circulation
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Solution Overview
Problem
Conventional blow molding apparatuses struggle to uniformly cool preforms after injection molding, leading to temperature unevenness and quality issues such as thickness unevenness and whitening in resin containers, especially when the cooling time is shortened.
Innovation Solution
A manufacturing apparatus and method that includes an injection molding part and a temperature adjustment part where the preform is inserted with an outer surface temperature higher than its glass transition temperature, cooled using a temperature adjustment core mold and cavity mold, and then blow-molded, with the temperature adjustment part configured to sandwich and circulate air to deform and cool the preform efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cooling time after injection molding is set short to reduce manufacturing time, then productivity is improved, but temperature unevenness in the preform cannot be sufficiently removed and manufacturing precision deteriorates
Solution Approach 1:
The temperature adjustment part is divided into multiple independent temperature zones with separate heating and cooling capabilities. This segmentation allows different regions of the preform to be cooled at different rates, enabling uniform temperature distribution to be achieved even when the overall cooling time is short, thus resolving the contradiction between productivity and temperature uniformity.
Solution Approach 2:
The temperature adjustment part performs preliminary cooling of the preform immediately after injection molding, before the blow molding step. By pre-adjusting the temperature distribution in advance, the system eliminates temperature unevenness early in the process, allowing the subsequent blow molding to proceed with uniform temperature conditions even when total cycle time is reduced.
2Productivity
If the cooling time is set short to increase productivity, then manufacturing efficiency is improved, but thickness unevenness and whitening occur reducing manufacturing precision
Solution Approach 1:
The temperature adjustment part uses segmented temperature control zones that can independently regulate cooling rates. This allows precise control over the cooling process to prevent excessive cooling in certain areas that would cause thickness unevenness and whitening, while still maintaining short overall cycle times for high productivity.
Solution Approach 2:
The system dynamically adjusts temperature parameters in different zones of the preform during the cooling process. By changing temperature parameters (heating or cooling) in specific regions based on real-time conditions, the system prevents thickness unevenness and whitening defects while maintaining short cycle times.
3Productivity
If the cooling time is set short to improve productivity, then manufacturing speed is increased, but whitening occurs reducing product quality
Solution Approach 1:
The temperature adjustment part performs preliminary temperature uniformization of the preform before blow molding. By pre-adjusting the temperature distribution to eliminate hot spots and unevenness in advance, the system prevents whitening defects during the subsequent blow molding process, ensuring high product quality even when cycle times are short.
Solution Approach 2:
The system uses dynamic parameter changes in the temperature adjustment part to control the cooling rate and temperature distribution. By adjusting temperature parameters in real-time during the short cooling period, the system prevents whitening while maintaining high productivity.
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 high-quality resin containers with reduced thickness unevenness and whitening, achieving a suitable temperature distribution for blow molding even with a shortened molding cycle time.
Implementation Method 1
the temperature adjustment part may be configured to circulate air inside the preform
Implementation Method 2
the preform is cooled to a predetermined temperature suitable for blow molding in the temperature adjustment part
Data Source
AI summary
A manufacturing apparatus for manufacturing a resin container including an injection molding part configured to injection-mold a preform, and a temperature adjustment part configured to adjust a temperature of the preform molded in the injection molding part. The manufacturing apparatus is configured to blow-mold the preform whose temperature has been adjusted in the temperature adjustment part. The injection molding part includes an injection core mold and an injection cavity mold, and both the injection core mold and the injection cavity mold include a flow path connected to a chiller in which coolant is configured to flow to cool the preform such that the preform is inserted into the temperature adjustment part in a state where an outer surface temperature of the preform is higher than a glass transition temperature of a material constituting the preform by 30° C. or higher and 60° C. or lower.