Sheet Metal Stretch-Bend-Draw Simulator for Skid Line Analysis
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Solution Overview
Problem
Current methods for addressing surface distortions in sheet metal products during stamping die development rely on trial-and-error due to a lack of comprehensive understanding of the mechanisms causing these distortions, known as 'skid lines', which are undesirable from a quality perception perspective but have little impact on the function of the sheet metal part.
Innovation Solution
A stretch-bend-draw simulator (SBDS) apparatus that measures pulling and clamping forces on sheet metal strips over a tool surface, allowing for experimental evaluation of proposed draw bead designs and analysis of surface distortions by varying the angle between the pulling direction and the back force direction, enabling the identification of optimal conditions to minimize or eliminate surface distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trial-and-error methods are used to resolve surface distortion problems during stamping die development, then the development process can proceed without comprehensive theoretical understanding, but the time and resources required increase significantly
Solution Approach 1:
The patent creates a simplified simulator apparatus that copies the essential mechanics of stamping die operations. The simulator uses a draw bead block, tool radius, and sheet metal specimen to replicate the stretch-bend-draw process at a smaller scale, allowing researchers to study surface distortion mechanisms without requiring full-scale stamping dies. This copying approach enables theoretical understanding to be gained much faster than through trial-and-error with production equipment.
2Loss of information
If comprehensive measurement of forces during stretch-bend-draw process is implemented, then understanding of surface distortion mechanisms improves, but device complexity increases
Solution Approach 1:
The simulator apparatus segments the measurement functions into distinct, modular components. Load cells are placed at specific locations to measure individual force components separately: clamping force in the draw bead block, pulling force applied to the specimen, and reaction forces at the base. This segmentation allows comprehensive force data collection while keeping each measurement subsystem simple and independent, avoiding the need for a single complex measurement system.
3Manufacturing precision
If multiple angles between longitudinal direction and back force direction are tested, then optimization of draw bead design improves, but the number of experiments required increases
Solution Approach 1:
The simulator apparatus incorporates a rotatable mounting plate that allows the draw bead block holder to be positioned at different angles relative to the longitudinal direction. This dynamic adjustment capability enables researchers to change the back force direction angle (θ) between experiments without rebuilding the apparatus or using multiple fixed configurations. The angle can be easily modified by rotating the mounting plate to the desired position and securing it, allowing systematic study of angle effects on surface distortion while maintaining efficient experiment progression.
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 SBDS apparatus provides direct measurements of in-plane and contact normal forces, enabling researchers to understand and mitigate surface distortions, thereby improving the quality of sheet metal products by optimizing the stretch-bend-draw process.
Implementation Method 1
a clamping force measuring means (e.g., a load cell) for measuring a clamping force resulting from the male and female draw bead blocks clamping on the sheet metal strip
Implementation Method 2
the draw bead block holder comprises (A) a compressing means (e.g., threaded shaft or screw press) for compressing the male and female draw bead blocks together to clamp the sheet metal strip therebetween
Implementation Method 3
the sheet metal drawing tool having a surface for contacting a sheet metal strip when the sheet metal strip is pulled across the sheet metal drawing tool surface to provide a pulling force measurement
Data Source
AI summary
A stretch-bend-draw simulator (SBDS) apparatus for approximating die stamping of a metal is disclosed. The simulator includes a tool having a surface for contacting a sheet metal strip clamped in a jaw grip adapted to pull the sheet metal strip to provide a force measurement. A tool holding and moving device can be included for mounting, translating, and positioning the tool with respect to the sheet metal strip. The tool can be mounted on the tool holding device at a distal end or on a mounting plate of the apparatus. The tool holding device is coupled to a contact force measuring load cell for measuring the contact force. A draw bead block holder is provided that is adapted to mount a corresponding male and female draw bead blocks. The holder includes a compressing means for compressing the draw bead blocks together to clamp the strip. A clamping force measuring load cell is provided for measuring a clamping force resulting from the draw bead blocks clamping on the sheet metal strip. The simulator can include a base clamping device for mounting the sheet metal strip at an opposite end. The base clamping device is positioned adjacent the draw bead block holder and coupled to a back force measuring means for measuring a back force resulting from holding the sheet metal strip while the jaw grip pulls the sheet metal strip. The apparatus is adapted to analyze skid lines on the sheet metal strip resulting from contact with the tool.