Deformable Punch Die Set for Defect-Free Closed Recess Forming
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Solution Overview
Problem
Existing methods for forming closed recesses in metal sheet materials, such as those used in automobile door panels, often result in product defects due to uneven stress distribution and material flow, leading to aesthetic and quality issues, and require significant labor and resources to adjust.
Innovation Solution
A die set with a deformable first punch made of polyurethane and a rigid second punch, where the first punch gradually compresses inward to form a closed recess without radial tensile stress, preventing material flow and using a large friction coefficient to ensure uniform deformation, along with an air vent hole to reduce gas-related defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If draw forming or shaping methods are used to form closed recesses in metal sheet materials, then the recess shape can be formed, but product defects such as depressions occur due to uneven stress distribution and material flow
Solution Approach 1:
The invention changes the physical state and mechanical properties of the punch from rigid to deformable. The first punch is made of deformable material (such as rubber or plastic) instead of rigid material, allowing it to deform during the forming process. This parameter change enables the punch to adapt to the sheet material's resistance, distributing stress uniformly and preventing material flow defects while forming the recess shape.
2Force
If strong pressure is applied within the range of 20 mm to 40 mm in the peripheral area of the recess to prevent material flow, then material flow can be restricted, but product defects still cannot be completely overcome and require significant labor and material resources for adjustment
Solution Approach 1:
The invention transforms the static rigid punch into a dynamic deformable punch. The first punch made of deformable material can dynamically adjust its shape and pressure distribution during the forming process. As the punch deforms, it automatically adapts to the sheet material's resistance, maintaining optimal pressure without requiring external adjustment mechanisms, thereby eliminating product defects while reducing adjustment work.
3Ease of manufacture
If a rigid punch with groove is used to form the recess, then the forming process can be completed, but the sheet material flows over the rounding corner into the recess due to free state and insufficient material pressing force
Solution Approach 1:
The invention changes the mechanical parameter of the punch from rigid to deformable. The deformable first punch can elastically deform during pressing, maintaining contact with the sheet material and providing continuous material pressing force. This prevents the sheet material from flowing into the recess by adapting to the material's resistance in real-time, ensuring uniform rounding corners while simplifying the forming process.
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 solution effectively prevents product defects by ensuring a closed recess is formed without tangential compressive stress, reducing labor and material costs, and improving the quality and stability of the forming process, allowing for simpler maintenance and reduced repair rates.
Implementation Method 1
the first punch presents certain deformability, as the pressure increases, the deformation firstly begins at the portion of the first punch in contact with the sheet material
Implementation Method 2
the first punch which presents certain deformability is made of an elastic material
Implementation Method 3
using a large friction coefficient to ensure uniform deformation
Implementation Method 4
along with an air vent hole to reduce gas-related defects
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The present invention relates to a die set for forming a closed recess in a metal sheet material, characterized in that, the die set has an upper die and a lower die, wherein the upper die is provided with a deformable first punch (7) which includes a first groove (17) for guiding deformation on a side facing the sheet material to be formed, and the lower die has a rigid second punch (11) which has a second groove (18) corresponding to the closed recess to be formed on a side facing the sheet material to be formed, and the first groove has an outer contour greater than that of the second groove so that the first groove (17) covers the second groove (18).