Orbiting Arbor Spin Forming for Thin-Walled Pipe Grooves
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Solution Overview
Problem
Existing methods for forming grooves in thin-walled pipe elements by cold working do not produce engagement features suitable for high-pressure and high-load applications, as they fail to match the performance of thicker walled pipe elements with cut groove systems.
Innovation Solution
A method involving a die with circumferential troughs and an arbor with ribs, where the arbor orbits within the die, increasing in diameter to form a groove with a smaller outer diameter than the rest of the pipe element, creating a shoulder and bead for enhanced mechanical coupling and fluid tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If thin-walled pipe elements are used for weight and cost savings, then weight and cost are reduced, but the engagement features formed by cold working do not provide adequate strength for high loads and pressures
Solution Approach 1:
The arbor is rotated in an orbit about the longitudinal axis of the die during the grooving process. This dynamic motion allows the arbor to progressively displace material and form a groove with enhanced engagement features (shoulder, groove, and bead) that provide adequate strength for high-load applications while still using thin-walled pipe elements
Solution Approach 2:
The engagement feature is segmented into three distinct components: a shoulder portion, a groove portion, and a bead portion. This segmentation allows each component to perform its specific function - the shoulder provides bearing surface, the groove provides key engagement, and the bead provides reinforcement - collectively achieving the required strength for thin-walled pipe elements
2Strength
If cut groove systems are used on thicker walled pipe elements, then adequate engagement features are produced for high loads and pressures, but material is removed from the pipe sidewall requiring thicker walls
Solution Approach 1:
The traditional mechanical cutting system is replaced with a cold working system that uses an orbiting arbor to plastically deform and displace material. This substitution eliminates material removal while still producing engagement features with adequate strength for high-load applications
Solution Approach 2:
The process changes the physical state and properties of the material through cold working. By applying controlled plastic deformation through the orbiting arbor, the material is reshaped into engagement features without removal, maintaining pipe wall thickness while achieving required strength
3Loss of substance
If cold working is used to form grooves in thin-walled pipe elements, then material is not removed and thinner walls can be used, but the engagement features do not match the performance of cut groove systems
Solution Approach 1:
The orbiting motion of the arbor provides dynamic control over material displacement. The orbital path and rotation speed can be precisely controlled to achieve the exact groove dimensions and engagement feature geometry required for high-precision applications, matching or exceeding cut groove systems
Solution Approach 2:
The cold working process with orbiting arbor allows for controlled material displacement with precise dimensional control. The process parameters (orbital diameter, rotation speed, arbor geometry) can be adjusted and controlled to achieve precise engagement feature dimensions that match design requirements
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
Enables the use of thin-walled pipe elements in high-pressure/high-load applications by forming precise engagement features that provide stronger, lighter, and more reliable joints with improved tolerance control and reduced residual stresses.
Implementation Method 1
increasing the diameter of the orbit while revolving the arbor so as to force the arbor against an inner surface of the pipe element; whereby the pipe element is pinched between the first circumferential rib and the first circumferential trough while revolving the arbor in the orbit of increasing diameter, thereby causing a portion of the pipe element between the first and second circumferential troughs to move radially inwardly away from the die thereby forming the groove
Data Source
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AI summary
A method of forming a groove in a pipe element by spin forming wherein the pipe element is pinched between an arbor revolving in an eccentric orbit of expanding diameter within the pipe element and an outer die which captures the pipe element. The pinching action causes a portion of the pipe element to move radially inwardly away from the die contrary to the direction of the motion of the arbor.