CMM Probe Alignment Fixture for Off-Machine Stylus Calibration
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Solution Overview
Problem
The existing method of angularly aligning a stylus extension relative to an adapter plate on a coordinate measuring machine is time-consuming and operator-dependent, often requiring multiple iterations to achieve acceptable alignment.
Innovation Solution
A calibration fixture with a front mounting surface, rear clamping surface, and access hole allows for angular adjustment of the stylus extension without occupying the CMM, using a vice to clamp the adapter plate and a dial indicator to check alignment, enabling efficient angular alignment perpendicular to the adapter plate's central axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the existing method of angularly aligning a stylus extension relative to an adapter plate on a coordinate measuring machine is used, then alignment can be achieved, but the process is time-consuming and operator-dependent, often requiring multiple iterations
Solution Approach 1:
The alignment process is segmented into distinct functional components: the fixture provides structural support and positioning references, the adapter plate holds the stylus extension, and the dial indicator measures angular deviation. This segmentation allows each component to be optimized independently and facilitates systematic troubleshooting and adjustment.
Solution Approach 2:
The fixture acts as an intermediary device between the adapter plate and the alignment measurement system. It provides a stable reference framework with precision machined surfaces and positioning features that mediate the transfer of angular orientation from the adapter plate to the measurable reference frame, enabling accurate alignment without direct CMM involvement during the alignment process itself.
2Measurement precision
If the existing method is used, then alignment can be achieved, but it requires significant operator skill and expertise
Solution Approach 1:
The fixture incorporates self-aligning features and precision reference surfaces that automatically establish the correct angular relationship between components. The rigid structure with machined reference surfaces and positioning features enables the alignment system to self-correct minor positioning errors, reducing dependence on operator skill for achieving accurate alignment.
Solution Approach 2:
The fixture transforms the alignment problem from a complex angular adjustment task into a simpler measurement task. By providing fixed reference surfaces and positioning features, it changes the parameters that need to be adjusted, allowing operators to achieve precise alignment through straightforward dial indicator readings rather than complex angular calculations and adjustments.
3Measurement precision
If angular adjustment is performed on the CMM, then alignment can be achieved, but the CMM is occupied and unavailable for other measurements
Solution Approach 1:
The alignment function is extracted from the CMM system and implemented in a separate, dedicated fixture. This allows the CMM to be removed from the alignment process entirely, freeing it for productive measurement tasks while the alignment operation is performed independently on the adapter plate using the fixture's reference surfaces and dial indicator measurement system.
Solution Approach 2:
The fixture serves as an intermediary alignment station that prepares the adapter plate for CMM measurement without requiring the CMM to be involved in the alignment process. The fixture's precision reference surfaces and positioning features mediate the alignment operation, creating a pre-aligned state that can then be transferred to the CMM for actual measurement work.
Data Source
AI summary
A fixture enables a stylus extension to be angularly aligned relative to an adapter plate that mounts onto a CMM probe head. Alignment may be carried out on a flat surface remotely from the CMM. The adapter plate is mounted to the fixture, which includes an access hole providing access to adjustment screws at the rear of the adapter plate. One or more lateral extensions are connected to the stylus extension to define a calibration axis perpendicular to a probe axis of the stylus extension and perpendicular to a central axis of the adapter plate about which angular alignment is desired. Angular adjustments of the stylus extension are made while the adapter plate is mounted to the fixture, and a degree to which the calibration axis is parallel to a plane of the flat surface is detected, for example using a dial indicator engaging points on the lateral extension(s).