Machining Axis Determination Using Reference Workpiece Comparison
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Solution Overview
Problem
Existing methods for determining the machining axis of rotary work blanks, such as crankshafts, require complex and expensive measurement devices to achieve minimal imbalance, and result in long cycle times.
Innovation Solution
A method using a measurement device to measure the spatial position of surface points on both a reference workpiece and a work blank, calculating the imbalance effect relative to a reference axis, and adding an empirically determined offset to determine the machining axis, allowing for accurate and efficient determination of machining axis locations without complex devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex and expensive measurement devices are used to measure workpiece areas left unmachined, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a reference workpiece that has already been machined to create a template or copy of the ideal geometry. This reference workpiece serves as a surrogate for the complex measurement apparatus, allowing simple measurement devices to achieve high precision by comparing the work blank against the known reference geometry rather than requiring absolute measurement accuracy
Solution Approach 2:
The invention replaces expensive, complex measurement devices with simple, inexpensive measurement apparatus. The reference workpiece acts as a reusable but simple standard that enables accurate measurements without requiring sophisticated equipment, effectively substituting a cheap object (simple measurement device + reference workpiece) for an expensive one (complex measurement device)
2Manufacturing precision
If complex measurement and calculation procedures are used to determine machining axis position, then manufacturing precision is improved, but productivity decreases due to long cycle times
Solution Approach 1:
The reference workpiece is prepared in advance with all the complex geometry and machining characteristics already established. This preliminary action transfers the computational and precision requirements to the reference creation phase, allowing subsequent work blanks to be measured and processed quickly by simple comparison rather than complex real-time calculation
Solution Approach 2:
By copying the ideal geometry into a physical reference workpiece, the patent eliminates the need for complex real-time measurements and calculations during production. The reference workpiece embodies the precise geometry that would otherwise require sophisticated measurement and computation systems, enabling fast, simple replication for multiple work blanks
3Adaptability or versatility
If measurements are taken on work blanks with varying geometries, then adaptability is improved, but measurement precision decreases due to sensitivity to measurement inaccuracies
Solution Approach 1:
The reference workpiece serves as an intermediary between the varying work blanks and the simple measurement device. Instead of measuring each work blank directly against ideal geometry (which amplifies measurement errors), the reference workpiece mediates the measurement process, providing a stable, known reference that compensates for variations in work blank geometry and reduces the impact of measurement inaccuracies
Solution Approach 2:
The reference workpiece creates a copy of the ideal geometry that can be used across multiple measurements. This copied reference standard allows the system to adapt to different work blanks while maintaining consistent measurement precision, as all measurements are referenced against the same known geometry rather than requiring absolute measurement accuracy for each varying part
Data Source
AI summary
In order to determine the machining axis of a rotatable workpiece blank, a reference workpiece, which has bearing surfaces concentric to its imbalance reference axis, and subsequently a workpiece blank are received in a measurement device, and as yet unmachined surface regions of the reference workpiece and of the workpiece blank are measured by a sensor device, and the measured position data are stored by a computer as a reference partial surface and a blank partial surface in a data storage device. The computer calculates deviations between the blank partial surface and the reference partial surface and, from these, an imbalance effect which is expressed by the position of the main axis of inertia of a given workpiece. The machining axis is calculated by adding an offset to the position of the main axis of inertia, which offset has been empirically determined with the aid of the actual imbalances of previously produced workpieces measured relative to the machining axis.