Workpiece Joining Alignment Using Adjustable Locators and 3D Best Fit
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Solution Overview
Problem
Conventional weld fixture technologies face challenges with dimensional variability in assembling automobile bodies due to part-to-part variation, leading to quality issues, high scrap rates, and reduced production throughput, as they rely on manual adjustments and shims to compensate for positioning errors.
Innovation Solution
A method and system that utilize three-dimensional data sets to determine optimal relative positioning of workpieces using adjustable locators and a processor-driven optimization algorithm to minimize discrepancies, eliminating the need for manual shims and improving precision in assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional weld fixtures with fixed locators are used to assemble body components, then the assembly process can proceed efficiently, but dimensional variability accumulates leading to quality issues and high scrap rates
Solution Approach 1:
The patent implements adjustable locators that can dynamically reposition themselves based on real-time measurement data from laser sensors. Unlike conventional fixed locators, these locators can adapt their positions during the assembly process to compensate for dimensional variations in individual parts, thereby maintaining high precision while preserving assembly throughput.
Solution Approach 2:
The system incorporates laser measurement sensors that continuously monitor the positions of body components and feed this data back to the control system. The control system then adjusts the locator positions in real-time based on this feedback, creating a closed-loop control system that eliminates dimensional variability accumulation and improves quality without reducing productivity.
2Manufacturing precision
If manual shimming and trial-and-error techniques are used to adjust locator positions, then some dimensional compensation can be achieved, but the process is time-consuming and reduces production efficiency
Solution Approach 1:
The patent replaces manual mechanical shimming operations with an automated electronic control system. Laser sensors measure part dimensions, a computer processes the data to calculate optimal locator positions, and automated actuators adjust the locators accordingly. This substitution eliminates time-consuming manual measurements and adjustments while achieving superior positioning accuracy.
Solution Approach 2:
The system performs preliminary measurement and calculation of the required locator adjustments before the actual assembly operation. By pre-determining the optimal positions based on laser scan data and processing the information through optimization algorithms, the system eliminates trial-and-error adjustments during production, significantly reducing adjustment time while maintaining high precision.
3Stability of the object's composition
If locator pins are sized to the largest possible diameter to eliminate positioning errors, then positioning stability improves, but interference fits and offsets cause stress and wear on locator pins
Solution Approach 1:
The patent employs dynamically adjustable locators that can change their positions rather than relying on oversized fixed locators. This dynamic adjustment capability allows the use of properly sized locators that fit holes without interference, eliminating the stress and wear caused by forced fits while maintaining positioning stability through active repositioning.
Solution Approach 2:
The system changes the positional parameters of locators in real-time based on measured part variations. Instead of using locators with fixed oversized dimensions, the system adjusts the location coordinates of locators to match the actual hole positions, thereby eliminating interference fits and offset stresses while maintaining positioning accuracy.
Data Source
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AI summary
Workpieces are placed in the workstation so one is in registration with a fixed locator. Measurement data are obtained reflecting the positions of the respective features of the workpieces and represented in a common reference frame associated with the fixed locator. A processor uses the collection of assembly data and the measurement data to define and store ordered pairs of mating feature locations. The pairs are then reoriented using a computationally discovered best fit. The position of a feature demarked for registration with the adjustable locator is calculated and the adjustable locator is caused to move to the calculated position of the feature demarked for registration thereby establishing a best fit orientation of the mating workpieces in physical space. The mating workpieces are then positioned in said best fit orientation by registration with said fixed and adjustable locators and then mechanically joining the mating workpieces.