Tapping Motor Current Monitoring for Screw Hole Quality Checks
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Solution Overview
Problem
Existing methods for determining the quality of screw holes formed by tapping are time-consuming and labor-intensive, requiring significant man-hours when using thread gauges for each hole.
Innovation Solution
A quality determination device and method that acquires the drive current from the motor of a machine tool during tapping and uses this data to determine the acceptance or rejection of screw holes based on predetermined ranges, allowing for efficient and easy assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thread gauge inspection is performed for each screw hole, then measurement precision is improved, but productivity deteriorates due to time-consuming manual inspection
Solution Approach 1:
The patent replaces the mechanical thread gauge inspection method with an electrical measurement system. Instead of manually screwing in a thread gauge to physically check each hole, the system uses a motor-driven tap with current sensors to electrically detect quality parameters during the tapping process itself, achieving both high precision and high speed
Solution Approach 2:
The patent performs quality determination during the tapping process rather than after completion. By measuring drive current characteristics while the tap is actively forming the screw hole, the system determines quality in advance before the workpiece leaves the machine, eliminating separate inspection time and maintaining precision
2Measurement precision
If manual thread gauge inspection is performed on all screw holes, then quality determination accuracy is improved, but loss of time increases significantly
Solution Approach 1:
The patent substitutes manual mechanical inspection with automated electrical measurement. The system continuously monitors drive current during tapping, automatically determining quality without requiring operators to manually inspect each hole, thereby maintaining accuracy while eliminating time loss
Solution Approach 2:
The patent makes quality determination continuous by measuring drive current throughout the entire tapping process. Instead of discrete manual checks after each hole, the system continuously monitors electrical parameters during active tapping, ensuring no quality issues are missed while minimizing inspection time
3Measurement precision
If dedicated thread gauges are used for quality determination, then measurement precision is improved, but device complexity increases due to additional tools and procedures
Solution Approach 1:
The patent makes the machine tool's motor serve multiple functions: it both performs the tapping operation and simultaneously enables quality determination through drive current measurement. This eliminates the need for separate dedicated thread gauges and inspection equipment, reducing device complexity while maintaining measurement precision
Solution Approach 2:
The patent enables the tapping system to self-diagnose quality issues by monitoring its own drive current characteristics. The motor and control system automatically detect quality problems during normal operation without requiring external inspection tools or additional equipment, simplifying the overall system
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 rapid and efficient quality determination of screw holes post-tapping, reducing time and labor by using drive current data to assess acceptance or rejection, thereby improving production efficiency.
Implementation Method 1
a motor (M) provided in a machine tool (12) that performs tapping
Data Source
AI summary
A quality determination device includes an acquisition unit for acquiring a drive current during tapping, from a motor provided in a machine tool that performs tapping, and a determination unit for determining acceptance or rejection of a screw hole formed by the tapping, based on the drive current, an electric power of the motor obtained from the drive current, or a torque of the motor obtained from the drive current.