Constant-Angle Addendum Surfaces for Tear-Free Sheet Forming
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Solution Overview
Problem
Current methods for generating addendum surfaces in sheet metal forming, particularly for Incremental Sheet Forming (ISF), are time-consuming and require extensive CAD work, lacking automation and the ability to produce surfaces with constant design wall angles without self-intersections.
Innovation Solution
A fully-automated, computerized method for generating a constant-angle addendum surface that surrounds and extends the CAD geometry of a sheet metal part, ensuring a constant slope and no self-intersections, thereby facilitating the prevention of tearing due to excessive wall thinning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If traditional manual CAD methods are used to generate addendum surfaces, then the surfaces can be customized, but the process is time-consuming and lacks automation
Solution Approach 1:
The system performs self-service by automatically generating addendum surfaces using computer algorithms that process the part geometry and generate the required surface extensions without human intervention, eliminating manual CAD operations
Solution Approach 2:
Manual mechanical CAD operations are replaced with computerized automated algorithms that calculate and generate addendum surfaces through computational processes, substituting human-operated mechanical drafting with automated digital generation
2Reliability
If addendum surfaces are generated with constant design wall angles, then tearing due to excessive wall thinning is prevented, but achieving constant angles without self-intersections is difficult
Solution Approach 1:
The system maintains constant design wall angles by controlling the geometric parameters of the addendum surface generation process, ensuring that the slope angle remains fixed throughout the addendum while adjusting other parameters to prevent self-intersections
Solution Approach 2:
The automated generation process incorporates feedback mechanisms that detect and prevent self-intersections by monitoring the generated surface geometry and adjusting the addendum construction to maintain constant angles without creating intersecting regions
3Manufacturing precision
If extensive CAD work is performed to generate addendum surfaces, then precise control over surface geometry is achieved, but the process becomes time-consuming and less productive
Solution Approach 1:
The system performs preliminary automated calculations and geometric constructions to generate the addendum surface geometry before any manual intervention is needed, pre-computing the precise surface definition based on the part geometry and desired wall angles
Solution Approach 2:
The time-consuming manual CAD operations are extracted and replaced with automated computer algorithms that perform the same geometric construction tasks, separating the computational generation process from manual drafting activities
Data Source
AI summary
A computer-implemented method of generating an addendum surface for use in forming a sheet metal part by using an Incremental Sheet Forming (ISF) manufacturing process, wherein the method includes: providing a Computer Aided Design (CAD) geometry of the sheet metal part to be formed; and generating an addendum surface that surrounds and extends the CAD geometry; wherein the addendum surface has a constant slope everywhere and has no regions of self-intersection. The addendum surface can be used to manufacture a male and/or a female underform tool for use in the ISF process, such as Two-Point Incremental Forming (TPIF). The addendum surface has a user-specified constant design wall angle, θc, which can be selected to prevent tearing of sheet metal parts during ISF due to excessive thinning at large wall angles (i.e., wall angles greater than 60°).