Numerical Control for Deep-Hole Boring Without Retraction Vibration
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Solution Overview
Problem
Existing numerical control devices for drilling cause significant vibration in machine tools due to sudden acceleration and deceleration of cutting tools during retraction, especially in deep hole drilling, which leads to faster tool wear and inaccurate cutting.
Innovation Solution
A numerical control device that includes a deep-hole drilling execution unit for performing cutting and cutting stop operations while rotating the cutting tool, and a chip removal time calculation unit that calculates the chip removal time based on the cutting tool's position and other parameters, allowing the cutting stop operation to replace the retraction operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a canned cycle (peck cycle) is used for deep hole drilling with repeated cutting and retraction, then chip clogging is prevented, but sudden acceleration and deceleration of the cutting tool causes significant vibration and faster tool wear
Solution Approach 1:
The patent changes the motion parameters of the cutting tool by eliminating sudden acceleration and deceleration during retraction. Instead of using rapid traverse speed for retraction, the tool maintains a constant cutting feed rate throughout the drilling process, including during retraction movements. This parameter change resolves the contradiction by preventing vibration while still enabling chip removal through controlled retraction at the chip removal time.
2Manufacturing precision
If a small retraction amount is instructed to reduce vibration, then tool wear is reduced, but the cutting tool cannot perform vertical cutting due to vibration from sudden acceleration/deceleration
Solution Approach 1:
The patent maintains continuous cutting action at a constant feed rate throughout the entire drilling process, including during retraction. The cutting tool does not stop cutting or change speed during retraction movements, ensuring continuous useful action. This eliminates the acceleration/deceleration cycles that cause vibration, thereby resolving the contradiction between maintaining cutting accuracy and avoiding vibration.
3Productivity
If rapid traverse speed is used for retraction operation after cutting, then chip removal efficiency is improved, but the cutting tool is significantly accelerated and decelerated causing vibration
Solution Approach 1:
The patent implements periodic retraction at calculated chip removal times while maintaining constant cutting feed rate. Instead of using rapid traverse for continuous retraction, the system performs periodic retraction movements at optimized intervals. This periodic action at constant speed eliminates the acceleration/deceleration vibrations while still achieving effective chip removal through timed retraction cycles.
Data Source
AI summary
Provided is a numerical control device that eliminates the need for rapid acceleration/deceleration of a cutting tool during boring and that is capable of minimizing vibration of a machine tool. This numerical control device comprises: a deep hole boring execution unit which performs deep hole boring by repeating a cutting operation for making a cut in a workpiece while rotating the cutting tool and a cutting halting operation for halting the cutting operation of the workpiece while rotating the cutting tool; and a chip-discharging time calculation unit which calculates a chip discharging time depending on the position of the cutting tool after each cut during the cutting operation. The deep hole boring execution unit performs the cutting halting operation during the chip-discharging time.