Retractable Forming Insert for Negative Draft Sheet Metal Release
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Solution Overview
Problem
Existing forming tool systems struggle to efficiently remove sheet metal articles with negative draft angles due to complexity and cost issues, particularly when deeply undercut sections require large curvilinear paths or pivoting of heavy tool components, which can be obstructed and lead to costly implementation.
Innovation Solution
A forming tool apparatus comprising a first and second forming tool, with a linearly movable insert and pressure pad assemblies, including temperature compensating spacer elements, allowing for gapless or variable-sized gaps to facilitate the formation and extraction of articles with negative draft angles, enabling the tool to lock and release the article effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pivot linkage is used to pivot the removable wall segment out of the forming position, then the undercut wall is pivotally lifted and releases the formed article for removal, but the system becomes very complex and costly due to the pivoting of a very large and heavy portion of the tool
Solution Approach 1:
The forming tool is divided into a stationary forming tool and a removable insert with the undercut wall segment. Only the small insert needs to be moved, not the entire large forming tool, thereby simplifying the mechanism while maintaining article removal capability
Solution Approach 2:
The undercut wall segment is extracted from the main forming tool as a separate removable insert. This allows the insert to be independently moved by a simple linear-drive mechanism rather than requiring complex pivoting of the entire tool assembly
2Ease of operation
If the removable wall segment encompasses the entire Class A region of the article, then the undercut wall can be pivotally lifted to release the article, but electrical connections and wire flexing fatigue become problematic
Solution Approach 1:
The Class A region forming surface is segmented into two parts: the stationary forming tool surface and the removable insert surface. This segmentation allows the insert to be small and linearly movable, eliminating wire flexing fatigue issues while maintaining precision forming capability
Solution Approach 2:
The undercut portion is extracted into a separate removable insert, isolating the precision forming surface from the moving mechanism. This ensures that electrical connections remain stationary while the insert moves linearly without rotational stress
3Ease of operation
If a curvilinear path with large radius is used for deeply undercut sections, then the finish-form tool can separate from the formed article, but the path may be obstructed by other portions of the finished article
Solution Approach 1:
Instead of moving the large finish-form tool along a curvilinear path to achieve separation, the invention inverts the approach by keeping the finish-form tool stationary and moving only the small insert linearly. This eliminates path obstruction issues entirely
Solution Approach 2:
The separation mechanism transitions from curvilinear motion in two dimensions to linear motion in one dimension. The insert moves perpendicular to the Class A boundary in a straight line, providing clear separation without requiring complex curvilinear paths that may be obstructed
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 allows for the precise formation and efficient removal of sheet metal articles with negative draft angles, reducing complexity and cost by using a linear-drive mechanism and pressure pad assemblies to manage thermal expansion, ensuring a gapless boundary for Class A surfaces and variable gaps for non-Class A areas, thus overcoming the limitations of prior systems.
Implementation Method 1
compensating for thermal expansion of the insert and recess
Data Source
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AI summary
A forming tool apparatus is provided for forming an article having a negative draft angle that locks the formed article within the forming tool. An insert, which is disposed within a recess defined in a forming surface of the forming tool, has a surface that cooperates with the forming surface of the forming tool to shape a metal blank into a desired final shape. In particular, the surface of the insert is shaped to define the negative draft angle feature of the formed article. Subsequent to forming the article, a linear-drive mechanism is activated to withdraw the insert away from the formed article, and thereby unlock the formed article from the tool. The formed article is then extracted from the tool along an extraction direction that is other than parallel to the direction along which the insert is driven.