Frusto-Conical Flange Welding for Plastic Tank Assembly
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Solution Overview
Problem
Large vertical cylindrical plastic tanks face challenges in shipping and assembly due to bulkiness and manufacturing variations, leading to fit-up difficulties and potential unsoundness of weld joints.
Innovation Solution
The use of frusto-conical shaped flanges with fusion weld elements and engagement tabs allows for self-centering and secure welding of tank components, enabling efficient assembly and integrity verification of the weld joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If large vertical cylindrical plastic tanks are made as separate nested parts for shipment, then shipping cost and space are reduced, but fit-up difficulty and weld joint reliability increase
Solution Approach 1:
The tank is divided into separate nested parts (top and base sections) that can be shipped independently in a compact configuration, reducing shipping volume and cost. These segmented parts are then assembled through welding to form the complete tank structure.
Solution Approach 2:
Frusto-conical flanges are pre-formed on the tank parts during manufacturing. These pre-formed conical surfaces serve as self-aligning features that automatically compensate for manufacturing variations and distortions, ensuring proper fit-up before welding occurs.
2Ease of manufacture
If conventional cylindrical flanges are used, then manufacturing is simpler, but fit-up precision deteriorates due to manufacturing variations and distortions
Solution Approach 1:
Frusto-conical flanges are used instead of conventional cylindrical flanges. The conical curvature provides self-aligning properties that automatically adjust for manufacturing variations, part distortions, and handling-induced misalignments, ensuring precise fit-up without requiring complex fixtures or manual adjustment.
Solution Approach 2:
The frusto-conical flange geometry introduces asymmetric tapering that creates a self-centering effect during assembly. The conical surfaces guide the parts into proper alignment through their geometric relationship, compensating for dimensional variations and distortions inherent in mass-produced plastic components.
3Manufacturing precision
If multiple pins or dowels are used to secure flange joints, then fit-up accuracy is improved, but device complexity and assembly time increase
Solution Approach 1:
The alignment function previously achieved through complex pin-and-dowel fixture systems is extracted and built into the flange geometry itself. The frusto-conical surfaces provide self-aligning capabilities without requiring external alignment fixtures, pins, or dowels, thereby eliminating the complexity of those additional components.
Solution Approach 2:
The frusto-conical flanges are self-aligning by design. The conical geometry automatically guides the parts into proper alignment during assembly through their geometric relationship, eliminating the need for external alignment fixtures or complex positioning mechanisms. The structure serves its own alignment function.
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 facilitates the shipment of tanks as nested elements, reduces assembly time, and ensures a strong, leak-proof weld joint by accommodating manufacturing variations and distortions, thereby improving the integrity and efficiency of the assembly process.
Implementation Method 1
Fusion weld elements are captured on the faying surfaces of the flanges of the assembled parts, and the elements melted by internal heating of metal portions of the elements
Data Source
AI summary
A plastic tank is comprised of two parts, a base and a top, that are permanently joined to each other by welding at a circumferential joint formed by two mating flanges of the parts. The faying surfaces of the flanges of the top and base have portions in the shape of a hollow truncated cone. Fusion weld elements are captured on the faying surfaces of the flanges of the assembled parts, and the elements melted by internal heating of metal portions of the elements.