In-Machine Optical Part Inspection for Fast Dimensional Control
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Solution Overview
Problem
Current methods for dimensional control in manufacturing, particularly in additive and subtractive processes, face challenges such as slowness, limited applicability to various machines, and inaccuracies due to environmental factors like chips and cutting fluids, especially when detecting deformable surfaces or complex geometries, and cannot reliably assess errors independent of machine axis uncertainties.
Innovation Solution
A system comprising a machine tool, a polyarticulated robot, and a computer with a three-dimensional digital model, using a contactless optical measurement system that acquires points outside the machine's working volume, allowing for rapid and precise dimensional control without modifying the machine, and includes a method to eliminate measurement influences from residues and singularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feeler control device is used inside the machine, then dimensional control can be performed without dismantling the part, but the measurement process becomes slow especially when many points need to be acquired
Solution Approach 1:
The patent replaces the mechanical feeler control device with an optical measurement system. The optical sensor captures images of the part surface, and the digital image processing system extracts dimensional information without physical contact. This substitution eliminates the mechanical probing process that was slow when acquiring many points, while maintaining measurement accuracy through optical detection methods.
Solution Approach 2:
The patent creates a digital copy of the part surface through optical imaging. Instead of physically probing each point with a feeler device, the system captures a comprehensive optical image and generates a digital representation. This digital model allows rapid extraction of multiple measurement points simultaneously, dramatically increasing measurement speed while preserving dimensional control reliability.
2Reliability
If measurement is performed inside the machine working volume, then the part can be inspected without repositioning, but environmental factors like chips and cutting fluid falsify measurements
Solution Approach 1:
The patent applies local quality by using image processing techniques that selectively analyze specific regions and features of the captured image. The system identifies and focuses on relevant geometric features while filtering out areas affected by chips and cutting fluid. This localized approach allows measurement to proceed in the contaminated environment without compromising accuracy.
Solution Approach 2:
The patent converts the harmful effect of environmental factors into a benefit through intelligent image processing. The system uses algorithms that can distinguish between actual part features and artifacts caused by chips or cutting fluid. By analyzing image patterns and comparing with expected geometric features, the system identifies and excludes false measurements, turning the contaminated environment from a liability into a manageable condition.
3Productivity
If a contactless optical measurement system is used outside the machine, then rapid acquisition of many points is possible, but the system becomes more complex requiring robot and carriage integration
Solution Approach 1:
The patent achieves universality by designing the robot-carriage-integration system to perform multiple functions. The same robotic mechanism that positions the optical sensor also enables the system to adapt to different part sizes, geometries, and measurement requirements. This multi-functional design consolidates what could be multiple separate systems into a single integrated platform, managing complexity while maintaining measurement speed and versatility.
Solution Approach 2:
The patent applies dynamics by making the measurement system adaptable and reconfigurable. The robot and carriage components can dynamically adjust their positions and orientations to optimize measurement of different part features. This dynamic capability allows the system to maintain high measurement speed across various part configurations without requiring multiple fixed installations, effectively managing system complexity through flexibility.
4Manufacturing precision
If traditional measurement methods are used, then they work for simple geometries, but they cannot reliably detect deformable surfaces or complex geometries
Solution Approach 1:
The patent replaces mechanical measurement approaches with optical imaging and digital image processing. This substitution enables the system to capture and analyze complex geometries and deformable surfaces that mechanical probes cannot reliably detect. The optical system provides comprehensive surface coverage and the digital processing algorithms can interpret complex geometric features, enhancing both precision and adaptability across different part types.
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
Enables fast and accurate dimensional control of parts during manufacturing, independent of machine axis precision, applicable to any machine type, and effectively differentiates between genuine defects and environmental artifacts, ensuring reliable quality assessment and correction.
Implementation Method 1
a contactless optical measurement system that acquires points outside the machine's working volume
Data Source
Figure 1A~1D
Figure 2
Figure 3
AI summary
The invention relates to a system for controlling a part being manufactured on a machine tool, said control being carried out in the same phase following a manufacturing operation, the part being in the working volume of said machine tool, characterized in that following a first manufacturing operation carried out on the part, a control operation is carried out on said part by means of the measuring device, said control operation comprising the steps of: i) moving the robot by means of the carriage in order to allow it to reach the access zone; ii) positioning the measuring device relative to the part by means of the robot; iii) acquiring a plurality of points on a surface of the part; iv) comparing the position of the points acquired in step iii) with the three-dimensional model included in the computer's memory means.