Slope-Synchronized ISF Tool Paths for Uneven Wall Angles
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Solution Overview
Problem
Incremental sheet forming (ISF) processes face challenges in producing contoured parts with uneven wall angles, resulting in surface imperfections like ridges and blemishes due to fixed step-downs, which require additional surface treatment and increase manufacturing time and cost.
Innovation Solution
A computer-implemented method and system generate slope synchronized tool paths by calculating step-down values based on the maximum slope angle of the part's surface, allowing for variable step-downs that adapt to changing wall angles, thereby improving the forming process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed or constant step-down value is used in ISF tool paths, then the tool path generation is simple and efficient, but surface imperfections such as ridges and blemishes occur on parts with varying wall angles
Solution Approach 1:
The patent applies dynamics by transitioning from a static, fixed step-down value to a dynamic step-down value that varies continuously along the tool path. The step-down value is calculated as a function of the local wall angle at each Z-level, allowing the forming process to adapt to changing geometric conditions and maintain surface quality across different slope regions.
Solution Approach 2:
The patent implements parameter changes by making the step-down value a variable parameter rather than a constant. The step-down value is determined based on the local wall angle parameter at each position, creating a relationship where the step-down varies proportionally with the tangent of the wall angle. This parameter adaptation eliminates surface imperfections while maintaining manufacturing efficiency.
2Ease of manufacture
If a fixed or constant step-down value is used in ISF tool paths, then the tool path is easier to generate, but additional surface treatment processes are required to remove surface imperfections
Solution Approach 1:
The patent applies preliminary action by calculating and determining the appropriate step-down values during the tool path generation phase, before the actual forming process begins. The system pre-computes the variable step-down values based on the part geometry and wall angle distribution, storing them for use during forming. This preliminary determination eliminates the need for post-processing surface treatments, saving time while maintaining ease of manufacture.
3Device complexity
If a fixed or constant step-down value is used in ISF tool paths, then the forming process is simpler to control, but the shape definition and quality of the formed part are poor
Solution Approach 1:
The patent implements feedback by using the local wall angle information (derived from the part geometry) to determine the appropriate step-down value at each position. The system continuously adapts the step-down parameter based on the local geometric conditions, ensuring optimal forming control throughout the process. This feedback mechanism improves shape definition and part quality while maintaining reasonable process control complexity.
Data Source
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AI summary
There is provided a computer implemented method for generating slope synchronized tool paths for incremental sheet forming (ISF) of a contoured part. The method includes performing a slope synchronized tool path application execution with a computer and a slope synchronized tool path application. The slope synchronized tool path application execution includes defining equally spaced apart Z values, along a Z-axis, that intersect a surface of the contoured part; determining, for the Z values, a slope factor, to define an array of Z values and corresponding slope factor values; and setting a current Z coordinate, and iteratively, calculating a stepdown; decrementing a current Z coordinate by the calculated stepdown; and determining an intersection of the surface with a horizontal plane at the current Z coordinate, to produce a contour tool path loop. The method includes sending an output file to a numerically controlled ISF machine, to incrementally form the contoured part.