Multi-Stage Sheet Forming for Steep Walls Without Tearing
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Solution Overview
Problem
Incremental sheet forming processes are ineffective for creating structures with steep walls greater than sixty degrees due to excessive thinning and risk of material tearing.
Innovation Solution
A multi-stage incremental sheet forming system that determines a convex hull of the target structure and uses a first tool path to form an intermediate structure, followed by a second tool path to create inward features, reducing material thinning and damage risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-stage incremental sheet forming process using a Z level tool path is used, then the forming process is simple and fast, but the sheet metal thins excessively and tears when forming steep walls at sixty degrees or greater
Solution Approach 1:
The forming process is divided into multiple stages: a first stage that forms an intermediate structure with gentle slopes, and a second stage that forms the final steep walls. This segmentation allows each stage to operate within safe deformation limits, preventing material tearing while achieving the desired final geometry.
Solution Approach 2:
The first stage performs preliminary forming to create an intermediate structure that serves as a foundation for the second stage. By pre-forming the basic shape with gentle slopes, the material is prepared in advance to withstand the subsequent steep wall formation without tearing.
2Shape
If incremental sheet forming is used to form steep walls at sixty degrees or greater, then the desired complex geometry is achieved, but the sheet metal thins to approximately one half of its original thickness and risks tearing
Solution Approach 1:
The formation of steep walls is segmented into two distinct stages. The first stage forms the intermediate structure with controlled thickness, and the second stage forms the final steep walls. This ensures that no single stage exceeds the material's deformation capacity, maintaining thickness control throughout the process.
Solution Approach 2:
The process changes the forming parameters between stages: the first stage uses parameters suitable for forming gentle slopes, while the second stage uses parameters optimized for steep wall formation. This parameter adjustment allows each stage to operate within safe deformation limits, preventing excessive thinning.
3Ease of manufacture
If a single-stage incremental sheet forming process is used, then the manufacturing process is simple, but the process is ineffective for creating structures with steep walls greater than sixty degrees
Solution Approach 1:
The manufacturing process is segmented into two stages, each with its own tool path. While this increases process complexity slightly, it enables the formation of steep walls that would be impossible with a single-stage process, significantly improving adaptability to complex geometries.
Solution Approach 2:
The intermediate structure serves as an intermediary between the initial flat sheet and the final complex geometry with steep walls. This intermediary form allows the transition from simple to complex geometry to occur in controlled steps, enabling the formation of steep walls while maintaining process control.
Data Source
AI summary
A multi-stage incremental sheet forming system includes a forming tool, and at least one control unit in communication with the forming tool. The at least one control unit is configured to determine a convex hull of a target structure to be formed by the forming tool. The at least one control unit is further configured to operate the forming tool according to a first tool path in relation to an initial structure to form an intermediate structure having a shape based on the convex hull of the target structure. The at least one control unit is further configured to operate the forming tool according to a second tool path in relation to the intermediate structure to form one or more inward features into the intermediate structure to form the target structure.