Linear Friction Welding Preheating Control
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Solution Overview
Problem
Linear friction welding processes face challenges with uneven heating of components, leading to premature localized welding and potential damage, particularly when dealing with components of varying surface smoothness, which complicates the process and may result in system damage.
Innovation Solution
A linear friction welding system that includes a ram oscillating along a welding axis, a hydraulic press, and a welding control system with a memory, program instructions, and a processing circuit to control the scrub load pressure based on surface area ratios, time, or movement, ensuring consistent preheating through a shaped charge portion, thereby reducing system complexity and achieving uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If LFW devices incorporate massive components to control momentum during rapid acceleration and deceleration, then the welding process can achieve necessary frequency and amplitude, but the device complexity and cost increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-heating the component surfaces before the main welding friction process. This pre-heating phase prepares the surfaces to reach optimal welding temperature more efficiently during the subsequent rapid oscillation, reducing the need for excessively massive components to sustain the required acceleration frequencies throughout the entire welding cycle.
2Productivity
If the scrub phase pressure is increased to plasticize the abutting surfaces quickly, then welding speed improves, but uneven heating causes localized plasticization and premature welding that can damage the system
Solution Approach 1:
The patent applies preliminary action by implementing a controlled pre-heating phase before the main scrub phase. This pre-heating uniformly raises the temperature of the component surfaces, ensuring that when the scrub phase begins, the heat distribution is already optimized. This prevents localized overheating and premature plasticization during the high-pressure scrub phase, maintaining system integrity while achieving welding speed.
Solution Approach 2:
The patent applies periodic action by dividing the welding process into distinct phases: a pre-heating phase followed by the scrub phase. This periodic structure allows the system to alternate between lower pressure uniform heating and higher pressure localized plasticization, preventing the harmful effects of immediate high-pressure contact on uneven surfaces while maintaining overall productivity.
3Temperature
If pre-heating is applied using external torches or inductive heaters, then uniform heating can be achieved, but the process complexity and equipment requirements increase
Solution Approach 1:
The patent applies self-service by utilizing the welding system's own hydraulic press and oscillation mechanism to generate the necessary pre-heating, rather than requiring separate external heating equipment. The initial contact and slight oscillations during the approach phase generate friction heat that pre-heats the surfaces uniformly, allowing the system to perform its own pre-heating function using components already present in the welding device.
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 provides consistent preheating and reduces system complexity by controlling the scrub load pressure, minimizing premature welding issues and maintaining the integrity of the welding process, resulting in a more reliable and efficient weld formation.
Implementation Method 1
a hydraulic press, and a welding control system operably connected to the hydraulic press and the ram
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
bringing a shaped charge portion of a first component to be welded into contact with a second component to be welded
Data Source
AI summary
A linear friction welding system in one embodiment includes a welding control system operably connected to a hydraulic press and a ram, the welding control system including a processing circuit operably connected to a memory and configured to execute program instructions stored in the memory to bring a shaped charge portion of a first component to be welded into contact with a second component to be welded, and establish an initial scrub load pressure between the two components based upon a ratio between initial surface area of a contact initiation portion of the shaped charge portion and a final surface area of the first component. The processing circuit increases pressure between the components from the initial scrub load pressure to a target scrub load pressure before terminating oscillation of the ram and establishing or maintaining a weld load pressure.