Thread-Cutting Vibration Phase Control for Better Chip Separation

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Solution Overview

Problem

Conventional low-frequency vibration thread cutting processes do not effectively adjust the phase or amplitude of vibration according to the number of cutting passes, leading to inadequate chip separation during the machining process.

Innovation Solution

A numerical control apparatus that includes a drive unit for the workpiece and cutting tool, a vibration unit to superimpose vibrations with a predetermined ratio to the workpiece rotation, and a thread-cutting vibration adjustment unit to shift the phase of vibration relative to the workpiece rotation phase with each cutting pass, enabling precise control of the vibration phase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If low-frequency vibration thread cutting is performed without adjusting vibration phase according to cutting pass number, then the machining process can be performed with simple control, but chip separation becomes inadequate

Engineering Contradiction:
Improvechip separation qualityVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The vibration phase is made dynamic by adjusting it according to the cutting pass number. The control system automatically modifies the vibration phase parameter for each pass, transforming a static vibration control into a dynamic one that adapts to the specific cutting conditions of each pass, thereby improving chip separation without requiring complex manual intervention

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The vibration phase parameter is changed systematically based on the cutting pass number. By modifying this key parameter dynamically, the system optimizes chip separation for each pass while maintaining relatively simple control architecture, resolving the contradiction between precision and complexity

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If vibration phase is adjusted for each cutting pass to improve chip separation, then chip separation quality improves, but control system complexity increases

Engineering Contradiction:
Improvechip entanglementVSAvoidvibration control mechanism
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The vibration phase adjustment follows a periodic pattern based on the cutting pass number. This systematic periodic modification of the vibration phase creates optimal conditions for chip separation in each pass while maintaining a relatively simple control mechanism that automatically executes the phase changes without complex decision-making

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The vibration phase is adjusted in advance based on the predetermined cutting pass number before each cutting operation begins. This preliminary adjustment ensures optimal chip separation conditions are established before cutting starts, eliminating the need for complex real-time adjustments during cutting

Inventive Principle:
Principle #10Preliminary action

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

This solution allows for effective chip separation by adjusting the vibration phase with each cutting pass, improving the thread cutting process efficiency and quality.

Implementation Method 1

a vibration unit to superimpose, on a movement of the first drive shaft, a vibration that is a reciprocating feed movement having a period having a predetermined ratio with a rotation period of the main shaft

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Data Source

PatentEP3213848B1Numerical control device
Publication Date: 2024.09.18 MITSUBISHI ELECTRIC CORP
  • EP3213848B1 patent drawingFigure 1
  • EP3213848B1 patent drawingFigure 2~3
  • EP3213848B1 patent drawingFigure 4~5

AI summary

A numerical control apparatus (1) includes: a drive unit (10) controlling a main shaft rotating a workpiece, a first drive shaft feeding to move a cutting tool relatively to the workpiece along a perpendicular direction to a lead direction of a thread formed in a machining process, and a second drive shaft feeding to move the cutting tool relatively to the workpiece along the lead direction; and a vibration unit (482, 483) superimposing, on movement of the first drive shaft, vibration that is a reciprocating feed movement having a period having a predetermined ratio with a rotation period of the main shaft, and performs a thread cutting process for forming a thread on the workpiece by moving the cutting tool and the workpiece relative to each other and performing a cut process more than once on the workpiece. The numerical control apparatus includes a thread-cutting vibration adjustment unit (484) controlling the drive unit to shift phase of the vibration with respect to phase of the main shaft by a predetermined vibration phase shift amount every time in the cut process performed more than once.