Machine Tool Tip Position Correction Using Laser Shade Detection
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Solution Overview
Problem
Existing machine tools face challenges in accurately aligning the position of a tool's tip after an orientation change or exchange, leading to level differences in curved surfaces due to orientation errors caused by thermal deformation and component misalignment.
Innovation Solution
A machine tool system that includes a mounting table, a tool with a tip, a shade detector for laser light, and a controller to control the tool's orientation and position, allowing for direct evaluation and correction of the tool's position before and after orientation changes or exchanges, ensuring smooth connection of curved surfaces without considering orientation errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tool exchange is performed based on tool length measurement, then tool position can be determined, but orientation errors cause level differences in curved surfaces
Solution Approach 1:
The patent replaces the mechanical measurement system (tool presetter) with an optical measurement system (laser displacement sensor). The laser sensor directly measures the tip position of the tool in the machining coordinate system, eliminating the need for mechanical tool length measurement and subsequent coordinate transformations that introduce orientation errors. This optical measurement approach directly provides the tip position data needed for accurate tool exchange without being affected by machine tool orientation inaccuracies.
Solution Approach 2:
The patent changes the measurement parameter from tool length (a single dimensional value) to tip position coordinates (multiple spatial coordinates). Instead of measuring only the length of the tool and calculating tip position through coordinate transformations, the system directly measures the X, Y, Z coordinates of the tool tip using a laser displacement sensor. This parameter change eliminates the accumulation of orientation errors that occur during coordinate transformations and provides more accurate tip position data for tool exchange.
2Device complexity
If machine tool orientation is assumed to be accurate, then tool position calculation is simplified, but thermal deformation causes orientation errors
Solution Approach 1:
The patent replaces the mechanical coordinate system (which is subject to thermal deformation and orientation errors) with an optical measurement system. The laser displacement sensor directly measures tip positions in the machining coordinate system without relying on the mechanical orientation accuracy of the machine tool. This substitution eliminates the need to account for thermal deformation effects in position calculations.
Solution Approach 2:
The patent introduces a laser displacement sensor as an intermediary measurement device between the tool and the control system. This intermediary directly measures the tip position and provides accurate data to the control system, bypassing the need for the control system to rely on mechanical orientation data that is affected by thermal deformation. The laser sensor acts as a mediator that provides accurate position information independent of machine tool orientation errors.
3Manufacturing precision
If tool tip position is directly measured with laser sensor, then orientation errors are eliminated, but measurement system complexity increases
Solution Approach 1:
The patent introduces a laser displacement sensor as an intermediary measurement device that directly measures tool tip positions. This intermediary provides accurate position data without being affected by machine tool orientation errors, as it measures in the machining coordinate system directly. The added complexity of the laser sensor is offset by the elimination of complex coordinate transformation calculations and the improvement in measurement accuracy.
Solution Approach 2:
The patent replaces the mechanical measurement and calculation system with an optical measurement system. The laser displacement sensor provides direct measurement of tip positions, eliminating the need for mechanical tool presetters and complex coordinate transformation algorithms. This substitution reduces computational complexity while improving measurement accuracy, as the optical system directly provides position data without being affected by mechanical orientation errors.
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 accurate matching of the tool's position before and after orientation changes or exchanges, ensuring seamless connection of curved surfaces and reducing level differences by directly addressing orientation errors in the machine tool's components.
Implementation Method 1
a shade detector which can provide an optical path of a laser light and detect a shade state of the laser light, a tip of the tool is moved from a predetermined position to the optical path of a laser light, and the laser light is shaded at the tip
Data Source
AI summary
A machine tool includes a mounting table, a tool, a shade detector, and a tool controller. A workpiece is placed on the mounting table. The tool includes a tip. The shade detector is fixed on the mounting table, provides an optical path of a laser light, and detects a shade state of the laser light. The tool controller is connected to the mounting table via a supporting structure and controls an orientation and a position of the tool. A reference point associated with the tool is provided to the tool controller. The tool controller corrects a position of the tip based on a difference between a position obtained by calculation of the reference point in the case where the tip is matched with a measurement position P of a laser light and a position of the reference point when the tip portion is actually matched with a measurement position while keeping the orientation of a tool.