Blow Molded Tank Base Protrusion Geometry for Welding
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Solution Overview
Problem
In blow molding of multi-layer plastic tanks, the penetration of a double lip during welding can deform the pre-form, especially the barrier layer, requiring precise pressure control to avoid excessive thinning, which is costly and equipment-intensive.
Innovation Solution
A base with a solid surface featuring protrusions and recessed areas, where the area without protrusions is at least equal to or greater than the area occupied by protrusions, limits penetration without requiring precise pressure control, ensuring secure welding and protecting the barrier layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure is increased during welding to ensure good quality welding, then welding quality is improved, but the barrier layer becomes excessively thin due to increased penetration
Solution Approach 1:
The pre-form is heated before welding to increase its plasticity and reduce resistance to the welding lip, allowing effective welding at lower pressures that prevent excessive barrier layer thinning
Solution Approach 2:
The invention changes the temperature parameter of the pre-form (heating it to 80-120°C) to modify its mechanical properties, making it more compliant during welding and reducing the need for high pressure that would otherwise thin the barrier layer
2Manufacturing precision
If pressure is reduced during welding to protect the barrier layer, then barrier layer thickness is maintained, but welding quality deteriorates
Solution Approach 1:
By changing the temperature parameter of the pre-form through heating, the material becomes more plastic and easier to weld, allowing adequate welding pressure to be applied without exceeding the threshold that would cause excessive barrier layer thinning
3Manufacturing precision
If precise pressure control equipment is used to limit penetration depth, then barrier layer thickness is maintained, but equipment cost and complexity increase
Solution Approach 1:
The invention replaces complex mechanical pressure control systems with a simpler thermal field approach, using pre-form heating to naturally regulate penetration depth through material property changes, eliminating the need for sophisticated pressure monitoring and control equipment
Solution Approach 2:
The invention transitions from controlling the mechanical parameter (pressure) to controlling the thermal parameter (temperature), using thermal treatment to achieve the desired welding outcome without complex pressure control systems
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 allows for secure welding of tank accessories without degrading the barrier layer, eliminating the need for precise pressure control and reducing equipment costs, while maintaining the integrity of the tank's barrier layer.
Implementation Method 1
a base made of plastic material for a tank accessory... protrusions which are designed to be welded on a pre-form during the production of the tank by blow molding
Implementation Method 2
applying the base against the pre-form by pressing it against the corresponding indentation, so as to transfer part of the heat of the pre-form to the protrusions of the base, so as to weld them on the pre-form
Data Source
AI summary
A base made from plastic material for a motor vehicle tank accessory, including protrusions to be welded to a preform during production of the tank by blowing the preform, wherein: the base includes a solid surface recessed from the protrusions, the solid surface including a part without protrusions and a part taken up by the protrusions, the area of the part of the solid surface without protrusions is at least equal to one times the area of the solid surface taken up by the protrusions, the height of the protrusions relative to the solid surface is between 0.6 mm and 0.8 mm.