Linear Friction Welder Phase Control
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Solution Overview
Problem
Linear friction welding (LFW) processes face challenges such as non-uniform heating along the welding axis due to linear movement, requiring complex and expensive machinery to control momentum and position accurately, leading to inconsistent welds and potential errors.
Innovation Solution
A linear friction welding system with a controller and motors that adjust the relative phase of power shafts to control oscillation amplitude and frequency, allowing precise control of pressure and movement to achieve consistent welds, using a cam assembly with an eccentric mechanism to optimize the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LFW systems are used to achieve necessary frequency and amplitude for welding, then welding capability is achieved, but the system requires massive components which are very expensive and large in size
Solution Approach 1:
The patent employs a dynamic vibration isolation system where the ram is allowed to vibrate freely at its natural frequency during the friction welding process. The vibration isolation elements (springs and dampers) enable the system to achieve the necessary vibration amplitude without requiring massive driving components, as the system dynamically adapts to the welding requirements rather than relying on oversized static components
Solution Approach 2:
The patent uses vibration isolation elements that counteract the inertial forces generated during vibration. The springs and dampers act as counterbalancing mechanisms that neutralize the momentum effects, allowing the system to achieve high-frequency vibration without requiring equally massive counterweight components to control the momentum
2Reliability
If the vibrated component moves beyond the corresponding edge of the stationary component, then friction welding occurs, but non-uniform heating occurs at the leading and trailing edges resulting in inconsistent welds
Solution Approach 1:
The patent incorporates positioning features and alignment mechanisms that pre-position the components before the friction welding process begins. The system establishes the correct relative positioning and maintains it throughout the welding process, preventing the vibrated component from moving beyond the corresponding edges of the stationary component and ensuring uniform heating across the weld interface
Solution Approach 2:
The patent employs control systems that monitor the welding process parameters and adjust the vibration amplitude and component positioning in real-time. This feedback mechanism ensures that the vibrated component maintains proper alignment with the stationary component throughout the welding process, preventing non-uniform heating at the edges and ensuring consistent weld quality
3Productivity
If relative movement is rapidly terminated to form a weld, then welding speed is improved, but momentum control becomes problematic especially for larger components
Solution Approach 1:
The patent utilizes the natural dynamic characteristics of the welding system by allowing the ram to vibrate at its natural frequency. The vibration isolation elements enable rapid termination of relative movement by naturally dampening the vibration through the isolation elements, eliminating the need for complex active momentum control systems while maintaining high welding speeds
Solution Approach 2:
The patent employs vibration isolation elements that automatically manage the momentum and vibration of the system without requiring external control mechanisms. The springs and dampers self-regulate the vibration and momentum effects, allowing the system to rapidly terminate relative movement and form welds without problematic momentum control issues
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
The system enables precise control of pressure, frequency, and amplitude, resulting in consistent welds with reduced errors and the ability to form high-quality welds using different materials without retooling, while minimizing the size and cost of the welding components.
Implementation Method 1
The cam assembly includes a cam follower, an inner power shaft, an outer power shaft, and an eccentric. The inner power shaft is rotated by the first motor and the outer power shaft is rotated by the second motor
Implementation Method 2
The FW process typically involves pressing one of the two components against the other component with a large amount of force and rapidly moving one of the two components with respect to the other component to generate friction at the interface of the two components. The pressure and movement generate sufficient heat to cause the components to begin to plasticize
Implementation Method 3
A linear friction welding system with a controller and motors that adjust the relative phase of power shafts to control oscillation amplitude and frequency
Data Source
AI summary
A linear friction welding system and method in one embodiment includes a first motor configured to rotate a first power shaft, a second motor configured to rotate a second power shaft, a memory including program instructions, and a controller operably connected to the first motor, the second motor, and the memory, and configured to execute the program instructions to identify a first current oscillation amplitude of a ram operably connected to the first power shaft and the second power shaft, determine a second desired oscillation amplitude for the ram, determine a minimum shift in relative angle between the first motor and the second motor to achieve the second desired oscillation amplitude, allocate the minimum shift in relative angle between the first motor and the second motor, and control the first motor and the second motor based upon the allocated minimum shift in relative angle.