Preform Neck Contour Optimization via Embossing and Cooling
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Solution Overview
Problem
Conventional preform production methods struggle to achieve an optimal neck contour for blow-molding, leading to inefficient material usage, unwanted material consumption, and the risk of sink marks due to premature freezing and shrinkage, which complicates the blow-molding process.
Innovation Solution
The method involves creating a thin-walled neck region beneath the transporting ring using either channels or slides in the mold or embossing elements during post-cooling, allowing for controlled reheating and deformation to achieve a more favorable temperature profile and contour, thereby optimizing the preform geometry for efficient blow-molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the wall thickness in the neck region is reduced to improve material efficiency, then raw material consumption is reduced, but the material freezes prematurely causing sink marks
Solution Approach 1:
The mold is divided into multiple independent cooling channels that can be controlled separately. This allows different cooling rates in different regions of the preform, enabling the neck region to be cooled at a rate that prevents sink marks while other regions cool faster to reduce overall material consumption.
Solution Approach 2:
Different cooling rates are applied to different regions of the preform. The neck region receives controlled cooling to prevent premature freezing and sink marks, while other regions are cooled more aggressively to reduce material consumption and improve efficiency.
2Stability of the object's composition
If intensive cooling is applied to prevent premature freezing, then material shrinkage is controlled, but the preform requires additional cooling cycles after demolding
Solution Approach 1:
The necessary cooling is performed during the injection molding process itself through the controlled cooling channels, rather than requiring additional cooling cycles after demolding. This preliminary cooling action ensures the preform is properly stabilized before ejection.
Solution Approach 2:
The cooling process continues efficiently during the injection molding cycle without interruption, maintaining optimal temperature control throughout the formation of the preform. This continuous controlled cooling eliminates the need for separate post-demolding cooling cycles.
3Productivity
If the temperature profile is made abrupt to optimize material drawing, then material stretching efficiency is improved, but the temperature transition becomes difficult to realize
Solution Approach 1:
The temperature control system is segmented into multiple independently controlled heating zones along the preform. This allows each zone to be heated to the optimal temperature for material drawing, creating an effective abrupt temperature profile that improves stretching efficiency while remaining manufacturable.
Solution Approach 2:
The temperature profile is made dynamic and adjustable during the blow-molding process. Heating elements can be activated or deactivated in specific zones to create the optimal temperature distribution for material drawing, achieving the desired abrupt transition effect through controlled dynamic adjustment.
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 enables more efficient heat transfer and material stretching during blow-molding, reducing raw material consumption and preventing sink marks, while maintaining the sealing function of the neck region, thus improving the quality of the final bottle product.
Implementation Method 1
the infrared heaters of the downstream blow-molding machines can introduce heat energy more efficiently
Implementation Method 2
continue with intensive cooling of the preform, following demolding, in relatively straightforward mold parts, so-called cooling sleeves
Data Source
AI summary
A method and device for producing an optimized neck contour on preforms below the neck which is optimal for subsequent stretch blow molding. The geometry has a significantly thinner wall thickness than the neck itself. The preform can only be produced in the injection molding tool, when axial channels are used on the point or the vanes produce the thin points on the preform during injection molding. The thin-walled geometry on the preform can be produced outside of the mold during post-cooling by embossing. The preform is then removed in a cooled receiving sleeve and is cooled in the body by intensive contact cooling while no cooling contact is made with the preform neck due to the initial position of the embossing element. Due to the reheating of the neck they can be mechanically deformed into a new geometry advantageous for blow molding and thus wall thickness can be influenced.