Spindle Contact Monitoring Using Vacuum Nozzle Pressure Sensing
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Solution Overview
Problem
Existing devices for monitoring contact on machine tools, particularly in gear processing machines, lack the accuracy and speed required to detect small changes in workpiece position due to contamination and tilts, leading to reduced machining accuracy and potential workpiece misalignment.
Innovation Solution
A device utilizing a vacuum nozzle and pressure sensor system that amplifies pneumatic signals to detect small changes in distance between a workpiece or tool and a support surface, enabling precise and reproducible monitoring of contact by generating a vacuum space and measuring pressure changes, which can reach negative values, thus expanding the measuring range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing contact monitoring devices are used, then the basic function of detecting workpiece presence is achieved, but the measurement precision is insufficient to detect small tilts and contaminations
Solution Approach 1:
The patent employs pneumatic measurement nozzles that emit air streams to detect workpiece contact and position. By measuring the backpressure generated when the air stream interacts with the workpiece surface, the system achieves high-precision detection of contact status, tilts, and contaminations without mechanical contact, thereby improving measurement precision while protecting workpiece machining accuracy
Solution Approach 2:
The system monitors changes in air pressure parameters as the workpiece moves or tilts. By detecting subtle variations in backpressure caused by changes in the air stream's interaction with the workpiece surface, the system can identify small tilts and contaminations, enhancing measurement precision without compromising manufacturing precision
2Productivity
If existing contact monitoring devices are used, then the monitoring function is provided, but the response speed is insufficient for fast workpiece changes
Solution Approach 1:
The pneumatic measurement system provides contactless detection through air streams, enabling extremely fast response times. The system can detect workpiece presence and position changes within milliseconds, supporting automated fast workpiece changes while minimizing measurement time and maximizing productivity
Solution Approach 2:
The patent replaces mechanical contact-based sensing with pneumatic field-based sensing. This substitution eliminates mechanical wear and inertia, enabling faster response times and higher productivity during automated workpiece changes while reducing the time lost to measurement
3Productivity
If the device is arranged on the rotatable spindle for fast measurement, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The measurement device integrated on the spindle serves multiple functions: detecting workpiece presence, determining workpiece position, identifying tilts, and detecting contaminations. This multi-functionality reduces the need for separate sensing systems, thereby managing device complexity while improving productivity through fast, integrated measurements
Solution Approach 2:
The patent combines the measurement nozzles and pressure sensors directly onto the spindle structure, merging the sensing function with the existing spindle assembly. This integration reduces the number of separate components and simplifies the overall device structure while enabling fast measurements that improve productivity
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
The device achieves high accuracy and reproducibility in monitoring contact, allowing for fast and reliable detection of small distances, even in the presence of contaminants, and can be compactly integrated onto a rotatable spindle for efficient operation.
Implementation Method 1
a vacuum nozzle arranged upstream of the measuring nozzle, which is configured to produce a vacuum in a vacuum space by a flow of a fluid medium through the vacuum nozzle
Implementation Method 2
at least one first pressure sensor or pressure switch which is configured to measure a measurement pressure in the vacuum space
Implementation Method 3
at least one measuring nozzle, which is arranged in a region of the support surface, in order to produce a fluid flow directed away from the support surface
Data Source
AI summary
The invention relates to a device for monitoring the contact of a workpiece (1) or tool on a spindle (2) of a machine tool, which device has a contact surface (3) for the workpiece (1) or tool. At least one measurement nozzle (4) is arranged in the region of the contact surface in order to produce a fluid flow directed away from the contact surface (3). Upstream of the measurement nozzle, the fluid flow is conducted through a vacuum nozzle, which can comprise a jet nozzle (7c) and a collector nozzle (7b). When the fluid medium flows through the vacuum nozzle, the vacuum nozzle produces a negative pressure in a negative pressure chamber (9c). A pressure sensor (6) or pressure switch senses a measurement pressure (p3) in the negative pressure chamber.