Machine Tool Condition Monitoring for Early Abnormality Detection
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Solution Overview
Problem
Conventional machine tool maintenance relies on operator judgment, leading to inconsistent and delayed detection of abnormalities, resulting in potential defective products and decreased productivity due to continued machining in abnormal states.
Innovation Solution
A preventive maintenance system that includes vibration, sound, and servo motor current value detection units, coupled with an abnormality determination unit, to automatically and mechanically assess machine tool conditions by comparing real-time data against normal state data, with features like detection start/end command setting, determination result display, and warning units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If operator-based determination of abnormality is used, then the system is simple to operate, but the determination precision and reliability are low due to subjective factors
Solution Approach 1:
The patent replaces the mechanical/manual inspection method with an automated detection system using sensors (vibration sensors, sound sensors, current sensors) and a control unit. This substitution eliminates subjective operator judgment and provides objective, precise measurements of abnormality indicators, directly resolving the contradiction between detection precision and system complexity.
Solution Approach 2:
The machine tool performs self-diagnosis through integrated sensors and control logic that automatically monitor operational parameters and detect abnormalities without external intervention. This self-monitoring capability improves detection precision while keeping the system relatively simple by utilizing the machine's own operational data.
2Productivity
If operator-based determination is used, then the device complexity is low, but the productivity decreases due to delayed abnormality detection
Solution Approach 1:
The detection system operates continuously during machine tool operation, constantly monitoring vibration, sound, and current parameters. This continuous monitoring enables immediate detection of abnormalities without interrupting the machining process, thereby maintaining productivity while eliminating detection delays associated with manual inspection.
Solution Approach 2:
The control unit receives real-time feedback from sensors and automatically compares measured values against predetermined thresholds. When abnormalities are detected, the system provides immediate feedback to stop machining, preventing production of defective products and avoiding the time loss associated with delayed manual detection.
3Reliability
If multiple detection parameters are monitored, then the reliability of abnormality determination improves, but the device complexity increases
Solution Approach 1:
The patent combines multiple detection functions (vibration sensing, sound sensing, current sensing) into a single integrated control unit that processes all sensor inputs. This merging approach improves determination reliability by considering multiple parameters simultaneously while managing system complexity through centralized control logic and unified data processing.
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 early and accurate detection of abnormalities, preventing defective products and machine failures by automating the determination process, ensuring continuous operation in a normal state and improving overall productivity.
Implementation Method 1
a vibration detection unit (for example, a vibration detection unit 13 to be described later) attached to a mechanism (for example, a spindle 2, a telescopic cover 10, or an ATC shutter 12 to be described later) of a machine tool (for example, a machine tool 1 to be described later) to detect vibration
Implementation Method 2
a sound detection unit (for example, a sound detection unit 15 to be described later) provided in the vicinity of the mechanism of the machine tool to detect acoustic waves produced during operation of the machine tool
Data Source
AI summary
A preventive maintenance system of a machine tool capable of making determination of presence of an abnormality mechanically and automatically, which has conventionally been performed on the basis of the feeling of an operator and detecting an abnormality more accurately in an earlier stage is provided. The preventive maintenance system includes: a vibration detection unit attached to a mechanism of a machine tool to detect vibration; a sound detection unit that detects acoustic waves produced when a work is machined by the machine tool; a servo motor current value detection unit that detects a current value of a servo motor; an abnormality determination unit that compares the vibration, the acoustic waves, and the current value of the servo motor during operation of the machine tool with vibration data, acoustic wave data, and current value data in a normal state set in advance to determine presence of an abnormality in the mechanism of the machine tool; and a detection start/end command setting unit that adds commands for a detection start point and a detection end point of at least one of the vibration, the acoustic waves, and the current value of the servo motor to a machining program.