Adaptive Workpiece Positioning for Imprecise CNC Parts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing CNC machining processes face challenges in accurately positioning and securing imprecise work pieces, such as castings and composite layups, due to their variable dimensions and constraints, leading to inefficiencies and errors in adaptive machining and fixturing methods, which are costly, inflexible, and require extensive customization and manual adjustments.
Innovation Solution
A system and method that adaptively positions a work piece to a non-adaptive fixture using a measuring apparatus and positioner, allowing a computer to determine an adaptive position for the work piece, enabling repeatable attachment to CNC machines without the need for adaptive machining or fixturing, using generic and flexible technologies like scanning and robotic arms to ensure precise alignment and orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If adaptive machining is used to accommodate variable work piece dimensions, then manufacturing precision is improved, but loss of time increases due to re-identification and re-programming for each work piece
Solution Approach 1:
The system performs preliminary measurement of the work piece and calculates the adaptive position before machining begins. The transformation matrix is pre-computed based on measured deviations, allowing the work piece to be positioned correctly in advance without time-consuming adjustments during the machining process.
Solution Approach 2:
The invention replaces manual measurement and programming operations with an automated optical measurement system and computer-controlled positioning. The measuring apparatus captures work piece geometry, and the computer automatically computes positioning transformations, eliminating the need for operators to manually re-identify and re-program each work piece.
2Manufacturing precision
If adaptive fixturing is used to move the work piece to the correct position, then manufacturing precision is improved, but device complexity increases due to customized movable fixtures
Solution Approach 1:
The system introduces a positioner as an intermediary device between the work piece and the fixture. This positioner, equipped with motors and encoders, acts as a mediator that can precisely adjust the work piece position without requiring the fixture itself to be complex or customized. The positioner handles all adaptive positioning operations while the fixture remains a simple, standardized component.
Solution Approach 2:
The positioner serves multiple functions: it holds the work piece, positions it accurately in three dimensions, and interfaces with both the measuring apparatus and the fixture. This multi-functional device eliminates the need for specialized adaptive fixtures, allowing the same positioning mechanism to work with various work pieces and fixtures.
3Adaptability or versatility
If adaptive fixturing with movable fixtures is used, then adaptability is improved, but ease of operation worsens due to manual adjustment requirements
Solution Approach 1:
The system replaces manual adjustment operations with automated motor-driven positioning. The positioner's motors and encoders automatically move the work piece to the correct position based on computer-calculated transformations, eliminating tedious manual adjustments while maintaining full adaptability to handle variable work piece dimensions and geometries.
4Manufacturing precision
If six degrees of freedom adaptive machining is used, then manufacturing precision is improved, but productivity decreases due to limited CNC machine capabilities
Solution Approach 1:
The system performs all positioning calculations and transformations before the machining operation begins. By pre-computing the adaptive position and preparing the transformation matrix in advance, the system eliminates time-consuming operations during machining, thereby maintaining high precision while improving productivity.
Solution Approach 2:
The system uses the CNC machine's existing capabilities to perform the machining operations without requiring advanced six-degree-of-freedom adaptive control. The positioning is handled separately by the positioner, allowing the CNC machine to operate at its full productivity potential while still achieving precise results through the pre-positioned work piece.
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
The Invention is a system and method for adaptively attaching a work piece, especially an imprecise work piece, to a non-adaptive fixture that can be repeatably attached to one or more CNC machines. The Invention allows a work piece to be set up once for multiple machining operations. The Invention avoids the potential for errors and the cost and complexity inherent in adaptive machining and adaptive fixturing.