Machine Tool Drawbar Position Sensing for Tool Mounting Errors
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Solution Overview
Problem
When machining workpieces with machine tools, foreign substances like chips and machining fluid can adhere to the tool and spindle, preventing adequate contact and leading to incorrect tool mounting, which affects machining accuracy.
Innovation Solution
A tool mount evaluation method using an induction type displacement sensor to measure the position of the draw bar and determine if the tool is correctly mounted on the spindle, by setting reference positions for each tool and evaluating the mounted state based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the tool is exchanged and mounted on the spindle, then the machining process can continue with different tools, but foreign substances may adhere to the contact portion between the tool and spindle, causing incorrect tool mounting and lowering machining accuracy
Solution Approach 1:
The patent applies preliminary action by measuring the draw bar position before tool mounting to establish a reference position, then comparing the actual position after mounting to detect deviations caused by foreign substances. This preliminary measurement and comparison mechanism enables early detection of incorrect mounting before machining begins, resolving the contradiction by maintaining productivity through quick tool exchanges while ensuring precision through position verification.
2Strength
If the draw bar draws the tool inward to fix it to the spindle, then the tool is secured for machining, but foreign substances prevent adequate contact between the tool and spindle, causing the tool to be fixed in an inclined state
Solution Approach 1:
The patent implements feedback by using a displacement sensor to continuously monitor the draw bar position and compare it against the reference position. When foreign substances cause the tool to mount incorrectly, the sensor detects the position deviation and provides feedback signal to the control device, which can then trigger an alarm or prevent machining. This feedback mechanism ensures that tool fixation strength is maintained while preventing incorrect positioning that would compromise machining precision.
3Measurement precision
If a displacement sensor is used to measure the draw bar position, then the tool mounting state can be evaluated, but the system complexity increases due to additional sensing and control components
Solution Approach 1:
The patent applies universality by designing the displacement sensor system to serve multiple functions: it measures draw bar position, detects tool mounting correctness, provides feedback for control, and can trigger alarms or prevent machining. By making the sensing system multi-functional, the patent reduces overall system complexity compared to having separate systems for each function, while maintaining high measurement precision for tool mounting evaluation.
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
Ensures accurate tool mounting by detecting foreign substances and manufacturing errors, improving machining accuracy by determining the correct position of the tool relative to the spindle.
Implementation Method 1
the measured position can be measured by an induction type displacement sensor
Data Source
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AI summary
Provided is a method for evaluating tool installation when fastening a tool (18) to a main shaft (14) of a machine tool (80), wherein the method includes a storage step for storing a reference location of a draw bar (22) at the time when the tool (18) is contacting a mounting seat of the main shaft (14), in a state in which foreign matter has been removed from the surface of the mounting seat and from the contacting surface of the tool (18). The method for evaluating tool installation includes a measuring step for measuring a measurement location of the draw bar (22) when the tool (18) is installed on the main shaft (14), and a determination step for determining the installation state of the tool (18) to be abnormal if a measurement-location error with respect to the reference location exceeds a predetermined determination range.