Core Rod Assembly with Zoned Temperature Control
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Solution Overview
Problem
In blow molding processes, particularly injection blow molding, the neck portion of preforms tends to stick to the core rod due to overheating, leading to residue buildup and production issues such as defects and downtime, as conventional heating methods fail to independently control the temperature of the neck and body portions.
Innovation Solution
A core rod assembly with dual, fluidly isolated temperature control systems allows for independent temperature management of the neck and body portions, using separate fluid pathways to maintain the neck at a lower temperature than the body, reducing sticking and residue formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single heated fluid distribution system is used to heat the core rod uniformly, then the preform is prevented from prematurely curing, but the neck portion becomes sticky and sticks to the core rod during ejection
Solution Approach 1:
The core rod heating system is segmented into two separate fluid distribution systems: a first system with a first fluid pathway for heating the body portion, and a second system with a second fluid pathway for heating the neck portion. These systems are fluidly isolated from each other, allowing independent temperature control of different zones on the core rod.
Solution Approach 2:
Different temperature zones are created along the core rod by providing separate heating control for the neck portion and body portion. The first fluid pathway heats the body portion to a first temperature, while the second fluid pathway heats the neck portion to a second temperature that is lower than the first temperature, optimizing each zone for its specific function.
2Productivity
If the core rod is heated to prevent premature curing, then the preform remains flexible for blowing, but the neck portion becomes tacky and causes production downtime
Solution Approach 1:
The temperature parameter is changed differently for different zones of the core rod. The body portion is maintained at a higher temperature to prevent premature curing and ensure blowing flexibility, while the neck portion is maintained at a lower temperature to prevent stickiness and residue formation, eliminating the need for production-stop wipe-downs.
3Manufacturing precision
If uniform heating is applied to the core rod, then the preform achieves consistent temperature for blowing, but the neck portion experiences sticky phase and adhesion
Solution Approach 1:
The uniform heating approach is segmented into zoned heating with separate fluid pathways for the neck portion and body portion, allowing each zone to achieve optimal temperature uniformity appropriate for its specific function while preventing the neck portion from entering the sticky phase.
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 solution effectively reduces the occurrence of neck sticking and residue on the core rod, minimizing production delays and defects in finished articles by allowing precise temperature control of the neck and body portions during the blow molding process.
Implementation Method 1
a first fluid distribution system for providing selective temperature control of a first portion of the core rod assembly and a second fluid distribution system for providing selective temperature control of a second portion of the core rod assembly
Implementation Method 2
The first and second fluid pathways may each form part of respective first and second fluid distribution systems for providing selective temperature control
Data Source
AI summary
A core rod assembly (10) for blow molding includes a core rod head (16), a first fluid pathway (A1) extending along a first length of the core rod head (16), and a second fluid pathway (A2) extending along a second length of the core rod head (16). The first and second fluid pathways (A1, A2) may be fluidly isolated from each other and provide selective temperature control of respective first and second portions of the core rod assembly (10) during the blow molding process. At least a portion of the first fluid pathway (A1) may be longitudinally offset from the second fluid pathway (A2) so as to define respective first and second temperature zones (zone 1, zone 2) along the respective first and second portions of the core rod assembly (10).