Optical Probe Surface-Normal Filtering for Complex CMM Profiles
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Solution Overview
Problem
Coordinate measuring machines (CMMs) face inefficiencies when measuring objects with complex geometries, requiring longer measurement times compared to manufacturing times, due to the need for slow and precise traversal of the CMM probe to ensure accurate data collection.
Innovation Solution
A method that segments the object into smaller groups based on a wrist angle, allowing for measurement with a single hardware orientation, filters 3D data sets to remove outliers, and interpolates surface data to produce a modified 3D data set, which is then corrected and merged to improve measurement efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the CMM probe traverses slowly and precisely around complex geometry objects to ensure accurate measurements, then measurement precision is improved, but measurement time increases significantly (3-5 times longer than manufacturing time)
Solution Approach 1:
The patent segments the complex geometry object into multiple smaller groups or regions, allowing the measurement process to be divided into discrete segments. This enables more efficient measurement paths within each segment while maintaining overall measurement accuracy, reducing the total time required to measure the entire complex object.
Solution Approach 2:
The patent employs dynamic measurement strategies that adapt the probe traversal speed and path based on the local geometry characteristics. In regions where high precision is critical, the probe moves slowly; in less critical regions, it moves faster. This dynamic adjustment optimizes the balance between measurement accuracy and measurement time.
2Productivity
If the CMM probe traverses quickly around simple geometry objects, then productivity is improved, but measurement precision may be compromised
Solution Approach 1:
The patent applies different measurement quality levels to different regions of the object based on their geometric complexity and importance. Simple geometry regions are measured with faster, lower-resolution passes, while complex critical regions receive slower, higher-resolution measurement. This local differentiation maintains productivity while ensuring precision where needed.
3Adaptability or versatility
If the wrist orientation is changed frequently to accommodate complex geometry measurement, then measurement coverage is improved, but measurement time increases due to repositioning
Solution Approach 1:
The patent segments the measurement task into groups that can be measured with a single wrist orientation. By dividing the complex geometry into measurable segments that align with the wrist's orientation capabilities, the system minimizes the number of repositioning operations required while still achieving complete measurement coverage.
Solution Approach 2:
The patent performs preliminary analysis of the object geometry to determine optimal wrist orientations and segment assignments before measurement begins. This pre-planning allows the system to organize measurement groups in a way that minimizes subsequent repositioning, improving overall measurement efficiency.
Data Source
AI summary
A method efficiently measures an object having a feature with a plurality of profiles each having a surface. The method provides a CMM having a wrist coupled with a measuring probe. The probe has an optical probe with an angle of incidence with respect to a surface normal of a plurality of points to be measured. The wrist has a first given orientation that is adjustable to a second given orientation. The method measures the feature to be measured by segment groups to obtain a 3D data set for each group. The method removes data points from at least one 3D data set that are outlier data points. The method interpolates the surface formed by the data points. The method calculates a surface normal vector for the data points set. The method removes data points from the interpolated 3D data set whose surface normal are outside the angle of incidence.