Rotor Forging Pre-Spin Balancing and Stress Relief
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Solution Overview
Problem
Conventional pre-spinning processes for rotor forgings are time-consuming and costly, requiring high rotational speeds to relieve residual stresses, which complicates balancing and increases the risk of premature machine failure due to high vibration levels and unbalance issues.
Innovation Solution
A method and system that balances a pre-spin machine with a rotor forging at a first rotational speed and then pre-spins it at a substantially greater speed, using a one per rev sensor for weight placement angle determination and a vibration sensor for weight addition, with high-density non-metallic balance weights placed on the inside surface to achieve balancing and reduce vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high rotational speeds are used to relieve residual stresses in the pre-spinning process, then the effectiveness of stress relief is improved, but the balancing complexity and machine wear increase
Solution Approach 1:
The patent applies preliminary balancing of the rotor forging before the pre-spinning process. By balancing the rotor at a lower speed first, the subsequent high-speed pre-spinning operation can proceed with reduced vibration and less risk of machine damage, while still achieving effective stress relief. This preliminary action eliminates the need for complex balancing procedures at high speeds.
2Reliability
If high rotational speeds are used to relieve residual stresses, then the stress relief effectiveness is improved, but the time required for the process increases
Solution Approach 1:
The patent performs balancing as a preliminary action before pre-spinning, allowing the actual stress relief process to proceed efficiently at high speeds without interruptions for balancing adjustments during the process.
Solution Approach 2:
The patent employs periodic monitoring of vibration levels during the pre-spinning operation. By periodically checking vibration rather than continuously adjusting, the process maintains effectiveness while minimizing total process time.
3Reliability
If conventional pre-spinning processes are used, then residual stresses are relieved, but the process is time-consuming and costly
Solution Approach 1:
The patent integrates balancing as a preliminary step that can be performed efficiently before pre-spinning, eliminating the need for repeated balancing operations during the process and thereby improving overall productivity while maintaining stress relief effectiveness.
Solution Approach 2:
The patent changes the operational parameters by conducting balancing at lower speeds before pre-spinning, rather than attempting to balance at high pre-spin speeds. This parameter change simplifies the balancing process and reduces overall process time and cost.
4Reliability
If high rotational speeds are used for pre-spinning, then residual stresses are effectively relieved, but machine wear and failure risk increase
Solution Approach 1:
The patent applies preliminary balancing to reduce vibration levels before subjecting the rotor to high-speed pre-spinning. This preliminary action protects the machine from excessive wear and potential failure during the high-speed operation, while still achieving the desired stress relief effectiveness.
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 reduces the time and cost of balancing and pre-spinning, while effectively relieving forging-induced residual stresses at rotational speeds above maximum operational speeds, minimizing machine wear and preventing premature failure.
Implementation Method 1
pre-spinning the rotor forging while mounted on the pre-spin machine at a second rotational speed substantially greater than the first rotational speed
Implementation Method 2
a vibration sensor is used for determining an amount of weight to add to a spinning assembly including the rotor forging during the balancing
Implementation Method 3
a one per rev sensor is used for determining a weight placement angle
Data Source
AI summary
A method and system for relieving forging induced residual stresses in a rotor forging balances a pre-spin machine with the forging mounted thereon at a first rotational speed and then pre-spins the forging with it mounted on the machine at a substantially greater second rotational speed. A one per rev sensor is used for determining a weight placement angle and a vibration sensor is used for determining an amount of weight to add to a spinning assembly including the forging during the balancing. High-density non-metallic balance weights adhesively attached on an inside surface of the forging or spinning assembly may be used. The rotational inertia of the spinning assembly may be checked during a spin up period by determining a rate of rotational acceleration vs. torque applied to the spinning assembly and used to stop the pre-spinning if it is to great.