Hot Press Quenching With Selective Die Gaps for Section Accuracy
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Solution Overview
Problem
The existing hot press processing methods, particularly the direct-cooling method, result in uneven temperature distribution and subsequent uneven thermal contraction and volume expansion in workpieces, leading to residual stress and unintentional deformation due to differential cooling rates across the workpiece.
Innovation Solution
The method involves forming gaps between the workpiece and molding dies during cooling, except for specific sections where accuracy is critical, allowing controlled deformation to release residual stress in other sections, thereby preventing unintentional deformation in high-accuracy areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If direct-cooling method is used to quench the workpiece, then cooling efficiency is improved, but temperature distribution becomes uneven and residual stress increases
Solution Approach 1:
The invention divides the workpiece into multiple sections with different gap settings relative to the molding dies. Specific sections maintain contact (zero gap) to ensure temperature uniformity and minimize residual stress, while other sections have intentional gaps to accommodate thermal contraction and prevent deformation. This segmentation allows different regions to experience different cooling conditions, resolving the contradiction between rapid cooling and uniform temperature distribution.
2Stability of the object's composition
If gaps are formed between workpiece and molding dies during cooling, then deformation due to residual stress is released, but processing accuracy in certain sections deteriorates
Solution Approach 1:
The invention applies different gap conditions to different local sections of the workpiece based on their specific requirements. Critical sections that require high precision maintain contact with the molding dies (zero gap) to ensure accurate shape and minimal deformation. Non-critical sections have intentional gaps to allow thermal contraction and stress release. This local differentiation resolves the contradiction between overall stress release and local precision requirements.
3Manufacturing precision
If uniform cooling is applied across the entire workpiece, then thermal contraction is uniform, but deformation control in specific sections becomes difficult
Solution Approach 1:
The invention segments the cooling approach by applying different gap conditions to different sections of the workpiece. This allows uniform cooling and thermal contraction in sections requiring dimensional control, while enabling controlled deformation in sections where adaptability is needed. The segmented approach resolves the contradiction between overall uniformity and local flexibility.
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 enhances processing accuracy by intentionally releasing residual stress in designated sections, ensuring that critical sections remain deformation-free and maintaining the structural integrity of the molded article.
Implementation Method 1
the thermal contraction occurs in the workpiece in accordance with the cooling before and after the removal from the dies
Implementation Method 2
the volume of the workpiece expands due to organization change in accordance with so-called martensitic transformation
Implementation Method 3
a heating step of heating the workpiece
Data Source
AI summary
A hot press processing apparatus 1 includes: a heating step of heating a workpiece W; a pressing step of press-molding, by an upper die 11 and a lower die 12, the workpiece W heated in the heating step after loading the workpiece W between the upper die 11 and the lower die 12; and a cooling step of bringing the coolant into contact with a front surface of the workpiece W that is molded and placed in a pressed state by the pressing step, to thereby cool the workpiece W and place the workpiece W in a quenched state. In the hot press processing apparatus 1, the workpiece W molded and placed in the pressed state by the pressing step forms gaps c2 with respect to both of the upper die 11 and the lower die 12 so as to allow deformation at time of the cooling step except for an accuracy-guaranteed section Wr in the workpiece W.