Preform Temperature Control for Thick Bottom Thin Trunk
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Solution Overview
Problem
Existing temperature control devices for preforms struggle to achieve a distinct temperature distribution between a thick-walled bottom and a uniformly thin-walled trunk in resin containers, making it difficult to produce containers with an aesthetic appearance similar to glass bottles, which are resistant to breakage and lightweight.
Innovation Solution
A temperature control apparatus and method that uses a combination of a temperature control pot and core to intimately contact the outer and inner surfaces of the preform, allowing for precise temperature control of the bottom and peripheral portions, enabling the formation of a thick-walled bottom and thin-walled trunk through controlled heating and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional temperature control device is used for the preform, then the temperature control is simple, but it cannot achieve a distinct temperature distribution between the bottom and trunk portions
Solution Approach 1:
The temperature control device is divided into separate heating and cooling units that can be independently controlled. The heating unit includes a heating roller and heating lamp, while the cooling unit includes a cooling roller with water circulation channels. This segmentation allows distinct temperature zones to be created at different locations of the preform, enabling precise temperature distribution control between the bottom and trunk portions.
Solution Approach 2:
Different temperature treatments are applied to different portions of the preform. The bottom portion receives heating treatment through the heating roller and heating lamp to increase wall thickness, while the trunk portion receives cooling treatment through the cooling roller to maintain uniform thin wall thickness. This local quality approach creates the desired thick-walled bottom and thin-walled trunk structure.
2Stability of the object's composition
If the preform is cooled to room temperature before blow molding, then the preform is stable, but the energy consumption increases and shapability decreases
Solution Approach 1:
The preform undergoes preliminary temperature control treatments before blow molding. The bottom portion is heated to a specific temperature range to ensure proper material flow and wall thickness during blowing, while the trunk portion is cooled to maintain dimensional stability. This preliminary temperature conditioning eliminates the need to cool the entire preform to room temperature, reducing energy consumption while maintaining stability where needed.
Solution Approach 2:
The temperature parameters of the preform are selectively changed in different regions. The bottom portion temperature is increased to improve shapability and reduce energy consumption, while the trunk portion temperature is decreased to maintain stability. This parameter change approach allows the preform to be in an optimal state for blow molding without requiring complete cooling to room temperature.
3Shape
If the bottom wall thickness is increased to achieve a quality appearance, then the aesthetic appeal improves, but the uniformity of wall thickness in the trunk portion becomes difficult to maintain
Solution Approach 1:
Different temperature treatments are applied to different portions of the preform. The bottom portion receives heating treatment through the heating roller and heating lamp to increase wall thickness, while the trunk portion receives cooling treatment through the cooling roller to maintain uniform thin wall thickness. This local quality approach creates the desired thick-walled bottom and thin-walled trunk structure with high precision.
Solution Approach 2:
The temperature control process operates continuously during preform production. The heating roller and cooling roller work simultaneously and continuously to maintain the desired temperature distribution, ensuring consistent wall thickness variation from bottom to trunk throughout production. This continuous action ensures uniform wall thickness in the trunk portion while maintaining the thick bottom.
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 resin containers with a thick-walled bottom and uniformly thin-walled trunk, enhancing their aesthetic appeal and resistance to breakage while maintaining uniform wall thickness and transparency.
Implementation Method 1
a temperature control pot contacting an outer circumferential surface of a bottom of a bottomed preform and a part of a peripheral portion of the bottomed preform continuous with the bottom; a temperature control block disposed outside the peripheral portion of the bottomed preform
Data Source
AI summary
The outer circumferential surface of a bottom 4 of a preform 1 and a lower site 3a of a trunk 3 continuous with the bottom 4 is mechanically brought into intimate contact with a cooling pot 16 to undergo reliable cooling. The trunk 3, excluding the lower site 3a of the trunk 3 continuous with the bottom 4, is heated to a predetermined temperature by a heating block 17. When blow-molded, the so treated preform 1 can provide a container having a bottom of a desired thickness and having a uniformly stretched thin-walled trunk.