Press-Formed Part Heat Holding for Faster Springback Stabilization
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Solution Overview
Problem
Press forming simulations have low shape prediction accuracy for metal parts with high strength, leading to significant shape variation due to springback, which complicates the manufacturing process and delays subsequent fabrication steps.
Innovation Solution
A press forming method involving heating the press formed part to a temperature between 130°C to 150°C for a short period, followed by cooling, to rapidly relax residual stresses and reduce shape variation, allowing for quicker stabilization of the part's shape after die release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If press forming is performed on high strength metal sheets to achieve weight reduction and collision safety improvement, then strength and safety are improved, but shape prediction accuracy deteriorates due to increased springback
Solution Approach 1:
The patent applies thermal parameter changes by heating the press formed part to a predetermined temperature (e.g., 100°C to 200°C) after press forming and before die release. This temperature parameter change accelerates stress relaxation and reduces the magnitude of springback, thereby improving shape prediction accuracy while maintaining the use of high strength metal sheets
Solution Approach 2:
The patent performs a preliminary heating action on the press formed part before die release. This preliminary thermal treatment prepares the material for controlled stress relaxation, allowing the shape to be stabilized before the actual die release occurs, thus improving manufacturing precision
2Loss of information
If conventional press forming simulation is used to predict springback, then prediction capability is provided, but shape prediction accuracy is insufficient for certain press formed parts
Solution Approach 1:
The patent introduces a feedback mechanism by measuring the actual shape of the press formed part after die release and comparing it with the simulated shape. Based on this comparison, the simulation parameters are adjusted to improve prediction accuracy for subsequent productions, thereby reducing the gap between predicted and actual shapes
3Manufacturing precision
If die design is adjusted to compensate for springback shape variation, then shape control is improved, but the time required for shape stabilization increases
Solution Approach 1:
The patent changes the temperature parameter of the press formed part after die release by applying controlled heating. This thermal parameter change accelerates the stress relaxation process, allowing the part to reach its stabilized shape faster, thus reducing the time loss while maintaining good shape control
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 method significantly reduces the time required for shape stabilization, enabling faster processing and reducing the risk of failures in subsequent fabrication steps by efficiently managing shape variation post-springback.
Implementation Method 1
a stress relaxation step of heating the press formed part to a predetermined temperature to accelerate stress relaxation and reduce the press formed part's residual stress
Implementation Method 2
a shape variation reducing step of reducing shape variation of the press formed part due to springback
Data Source
AI summary
A press forming method reduces a time for chronological shape variation of a press formed part after occurrence of springback at a moment when the press formed part is released from a die, and includes: forming the press formed part by press forming with a metal sheet by using the die; releasing the press formed part formed by press forming, from the die; fitting the press formed part released from the die into the die and securing the press formed part in conformity with a shape at a bottom dead center of forming; heating the press formed part fitted into the die to a first temperature higher than room temperature and holding the press formed part at the first temperature for a predetermined time period of less than 30 minutes; and cooling the press formed part heated and held, to a second temperature lower than the first temperature.