Numerical Control Device for Dynamic Tapping Acceleration
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Solution Overview
Problem
Conventional numerical control devices for machining fail to accurately control tapping operations across varying tap diameters, leading to overload, inaccurate machining, and prolonged machining times due to fixed velocity gradients and neglect of cutting load dynamics.
Innovation Solution
A numerical control device that synchronizes main spindle and feed shaft movements, featuring a program analysis unit, gradient determination unit, interpolation and acceleration/deceleration processing unit, and synchronization error adjustment, which dynamically adjusts acceleration and deceleration velocities based on tap diameter and cutting load torque to optimize machining precision and time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant velocity gradient is used during acceleration/deceleration, then the control is simple, but overload occurs and accurate machining cannot be performed when tap diameter varies
Solution Approach 1:
The patent applies dynamics by making the acceleration/deceleration gradient variable rather than constant. The control device dynamically adjusts the velocity gradient based on the tap diameter being used, allowing the system to adapt to different cutting loads. This resolves the contradiction by maintaining control simplicity through automated adjustment while improving reliability and machining accuracy across varying tap sizes.
Solution Approach 2:
The patent changes the parameter of velocity gradient from a fixed constant to a variable parameter that depends on tap diameter. By establishing a relationship between tap diameter and appropriate velocity gradient values, the system optimizes acceleration/deceleration characteristics for each specific tapping operation, preventing overload while maintaining machining accuracy.
2Manufacturing precision
If a larger time constant is set for small pitch tapping, then the main spindle overshoot is avoided, but the machining time increases
Solution Approach 1:
The patent changes the time constant parameter dynamically based on the pitch of the thread being tapped. Instead of using a fixed large time constant for all operations, the system adjusts the time constant to be appropriate for each specific pitch value, achieving both overshoot prevention and reduced machining time by optimizing the parameter for each operation type.
Solution Approach 2:
The system dynamically adjusts the time constant based on real-time operational parameters (pitch value), allowing the control characteristics to adapt to different tapping conditions. This dynamic adjustment enables the system to achieve stable control without excessive machining time for each specific pitch.
3Productivity
If the velocity gradient is set for small tap diameter, then the machining time is short, but machining accuracy deteriorates when tapping with large tap diameter
Solution Approach 1:
The patent implements parameter changes by establishing a correspondence between tap diameter and velocity gradient. The control device automatically selects the appropriate velocity gradient based on the tap diameter being used, ensuring optimal acceleration/deceleration characteristics for each size. This prevents both overload on large taps and excessive machining time on small taps, maintaining both productivity and precision across all tap sizes.
Data Source
AI summary
In order to enable tapping to be performed precisely and with an appropriate machining time irrespective of the diameter of a tapping tool, a configuration of the present invention includes: a program analysis unit (12) that analyzes a loaded machining program and extracts thread-related information in tapping; a gradient determination unit (14) that determines acceleration regarding movement velocity of the main spindle or the feed shaft on the basis of the thread-related information obtained by the program analysis unit (12); and an interpolation and acceleration/deceleration processing unit (13) that generates a movement command for the main spindle and the feed shaft using the acceleration determined by the gradient determination unit (14). In addition, the gradient determination unit (14) varies the acceleration during acceleration/deceleration of the main spindle or the feed shaft in accordance with the diameter of a tapping tool.