Resin Preform Air Cooling for Shorter Blow Molding Cycles
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Solution Overview
Problem
Existing hot parison blow molding methods struggle to achieve high versatility in shortening the molding cycle time, particularly for containers like cosmetic bottles, as they require specialized preform shapes and cannot efficiently cool the preforms to optimize the molding process.
Innovation Solution
A method involving an injection molding step, a temperature adjustment step where the preform is cooled from both the inner and outer sides using air convection, and a blow molding step to produce resin containers, utilizing a mold unit with an air introduction member for controlled air flow to adjust and cool the preform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the preform is cooled only from the outer side using conventional mold cooling, then the cooling process is simple, but the molding cycle time cannot be sufficiently shortened
Solution Approach 1:
The cooling process is segmented into two independent cooling paths: outer surface cooling through the mold cavity and inner surface cooling through the air introduction member. This segmentation allows both cooling surfaces to operate simultaneously, doubling the effective cooling area and reducing the molding cycle time without requiring an overly complex integrated system.
Solution Approach 2:
The air introduction member is nested within the mold cavity structure, with air supply channels positioned inside the cavity to directly contact the preform's inner surface. This nested configuration enables inner surface cooling while utilizing the existing mold structure, avoiding the need for completely separate cooling systems.
2Productivity
If a special preform shape is adopted to shorten injection molding time, then the molding cycle is shortened, but the method cannot cope with diverse container types and has low versatility
Solution Approach 1:
The dual cooling system (mold cavity cooling + air introduction member cooling) is designed to be universally applicable to different container types including cosmetic bottles and other thick-walled containers. The system can handle various preform shapes and sizes by adjusting cooling parameters, making it a multi-functional solution that improves productivity without sacrificing versatility.
Solution Approach 2:
The cooling effectiveness is controlled by adjusting parameters such as air supply pressure, air flow rate, and cooling medium temperature rather than changing the fundamental preform shape. This allows the same mold design to efficiently produce different container types by simply modifying operational parameters, thereby maintaining high versatility while achieving short molding cycles.
3Strength
If the preform thickness is increased for cosmetic containers, then the container strength is improved, but the cooling time increases and productivity decreases
Solution Approach 1:
The thick preform is cooled through segmented cooling paths: the outer surface is cooled through the mold cavity while the inner surface is cooled through the air introduction member. This dual-path cooling approach creates a temperature gradient that efficiently removes heat from the thick material without requiring excessive cooling time, thus maintaining both container strength and productivity.
Solution Approach 2:
Instead of cooling only from the external dimension, the system introduces cooling from the internal dimension through the air introduction member. This adds another cooling dimension, effectively cooling the thick preform from both inside and outside simultaneously, which dramatically reduces cooling time while preserving the necessary wall thickness for strength.
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 method allows for the efficient production of resin containers with optimized cooling, reducing the molding cycle time while maintaining the physical properties and aesthetic quality of the final product, even with general-purpose resins.
Implementation Method 1
air is supplied from a blowing port of the air introduction member into the preform, and the air is discharged from a discharge port of the air introduction member to an outside of the preform, so that the preform is in close contact with an inner wall of the cavity mold and is cooled
Implementation Method 2
the preform is in close contact with an inner wall of the cavity mold and is cooled
Data Source
AI summary
Provided is a method for manufacturing a container 10 made of resin, the method including an injection molding step S1, a temperature adjustment step S2, and a blow molding step S3. In the temperature adjustment step S2, a preform 11 is accommodated in a cavity mold 31, an air introduction member 32 is brought into airtight contact with the preform 11, the air is supplied from a blowing port of the air introduction member 32 into the preform 11, and the air is discharged from a discharge port of the air introduction member 32 to an outside of the preform 11, so that the preform 11 is in close contact with an inner wall of the cavity mold 31 and is cooled.