Incremental Forging Universal Toolset Reduces Residual Stresses
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Solution Overview
Problem
Existing metal forming processes, such as machining and die forging, are inefficient and costly due to material waste, high residual stresses, and the need for unique dies, which limits the achievement of optimal material properties in precipitation hardened aluminum alloys.
Innovation Solution
A method and apparatus for incremental forging using a common toolset to heat and plasticize workpieces, extruding material into local cavities formed by the tools, allowing for the creation of parts without part-specific tools or dies, thereby reducing material usage and tooling costs while improving mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If die forging techniques are used to fabricate unitary metallic parts, then the parts can be produced with good mechanical properties, but the process becomes expensive and involves long lead times due to the need to fabricate unique dies for each part
Solution Approach 1:
The patent employs a universal forging toolset that can form multiple different features (flanges, stiffeners, lugs, etc.) on various workpieces without requiring part-specific dies. The system uses a library of interchangeable forging tools that can be selectively applied to different locations and orientations, allowing one toolset to perform the functions previously requiring multiple unique die sets.
Solution Approach 2:
The patent segments the forging process into discrete, localized operations. Instead of using a single complex die to form an entire part, the system applies multiple simple forging tools at different locations and times to build up the final geometry incrementally. This allows the forging process to be broken down into manageable steps that can be performed with standardized tooling.
2Manufacturing precision
If machining blocks or plates is used to fabricate metallic parts, then parts can be produced with good dimensional control, but the process is time consuming and expensive because a relatively large percentage of the blank becomes waste material
Solution Approach 1:
The patent changes the physical state and properties of the material locally during the forging process. By applying heat and pressure through the forging tools, the material transitions from a rigid solid to a plasticized state that can be formed into the desired geometry. This allows the material to flow and conform to the target shape rather than being removed by machining, significantly reducing waste.
Solution Approach 2:
The patent performs preliminary heating of the workpiece and/or forging tools before the actual forging operation. This pre-heating softens the material in advance, making it more plastic and easier to form. By preparing the material beforehand, the forging process can achieve complex geometries with minimal material removal, unlike machining which requires starting with a large blank.
3Ease of manufacture
If conventional forging processes are used on precipitation hardened aluminum alloys, then parts can be formed, but maximum material properties are not achieved and high residual stresses remain
Solution Approach 1:
The patent applies local heating and forging operations to specific regions of the workpiece rather than treating the entire part uniformly. This localized approach allows different portions of the alloy to be processed at optimal temperatures for their specific geometric requirements, preserving the precipitation hardening characteristics and minimizing residual stresses that would result from global heating and forging.
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
This approach enables the efficient fabrication of wrought or near-net shaped parts with reduced residual stresses and tooling costs, allowing for the production of parts with improved mechanical properties and reduced material usage.
Implementation Method 1
A second tool in the toolset is used to plasticize and extrude a portion of the workpiece into the cavity. The tool used to plasticize a portion of the workpiece may be used to heat the workpiece through frictional engagement
Data Source
AI summary
Any of various features of a workpiece are forged by a common set of tools. The feature (76) is incrementally forged as the tool set (40) is moved to successive forging locations on the surface of the workpiece. One of the tools (66) is used to plasticize and extrude a portion of the workpiece (32) while one or more of the other tools (70,72,74) are used to form dams that contain and shape the extruded portions.