Tailstock Pressing Control for Fast Abutting and Precise Force

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Solution Overview

Problem

Existing methods for pressing a tailstock in machining apparatuses fail to accurately control the target pressing force, leading to distortion of the workpiece and/or tailstock due to the use of temporary pressing speeds.

Innovation Solution

A method involving setting a target pressing force, controlling the tailstock movement with an actuator, detecting pressing through input changes, and adjusting the speed to stop and reposition the tailstock at a lower speed to achieve precise pressing force while minimizing distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the tailstock is pressed at a temporary pressing speed to move quickly toward the workpiece, then the abutting time is shortened and productivity is improved, but distortion of the workpiece and/or tailstock occurs and the target pressing force cannot be accurately controlled

Engineering Contradiction:
Improveabutting timeVSAvoidpressing force control accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The pressing process is divided into two distinct phases: a first pressing phase at a first pressing speed (higher speed) and a second pressing phase at a second pressing speed (lower speed). This segmentation allows the system to benefit from both high-speed abutting and precise force control, resolving the contradiction between productivity and precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressing speed is dynamically adjusted based on the pressing phase. The system transitions from a higher first pressing speed during the initial abutting phase to a lower second pressing speed during the final pressing phase. This dynamic speed adjustment enables both quick positioning and accurate force control.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the tailstock is pressed at a temporary pressing speed to reduce abutting time, then productivity is improved, but distortion of the workpiece and/or tailstock occurs

Engineering Contradiction:
Improveabutting timeVSAvoidworkpiece distortion
Core Design Contradiction:
ProductivityVSShape

Solution Approach 1:

The pressing operation is segmented into an initial high-speed phase for quick positioning and a final low-speed phase for distortion-free pressing. This segmentation ensures that the workpiece is not subjected to high-speed impact during the critical final pressing stage, preventing distortion while maintaining overall productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary high-speed movement to position the tailstock near the workpiece, then transitions to low-speed pressing for the actual contact. This preliminary action separates the transportation function from the pressing function, allowing distortion-free pressing while maintaining short overall abutting time.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the tailstock is pressed at a lower speed to avoid distortion and control pressing force accurately, then manufacturing precision is improved, but the abutting time increases and productivity decreases

Engineering Contradiction:
Improvepressing force control accuracyVSAvoidabutting time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The pressing process is divided into two phases with different speed characteristics. The first phase uses higher speed for quick positioning, while the second phase uses lower speed for precise force control. This segmentation allows the system to achieve both fast abutting and accurate pressing force control without compromising either objective.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressing speed is dynamically optimized for each phase of the operation. The system uses higher speed during the initial approach and lower speed during the final pressing, allowing the process to adapt speed requirements to the specific operational phase, thereby achieving both productivity and precision.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4238674B1Method for pressing tailstock of machining device, pressing device, computer program, and computer-readable storage medium
Publication Date: 2025.08.13 YAMAZAKI MAZAK KK
  • EP4238674B1 patent drawingFigure 1
  • EP4238674B1 patent drawingFigure 2
  • EP4238674B1 patent drawingFigure 3

AI summary

In a method for pressing a tailstock of a machining apparatus, a target pressing force for pressing the tailstock against a workpiece attached to a spindle in a first direction along a rotation axis of the spindle is set. An actuator for controlling a movement of the tailstock and a pressing force for pressing the tailstock against the workpiece is driven to move the tailstock in the first direction at a first speed. Upon detection of pressing, the movement of the tailstock is stopped. The tailstock is moved by a first distance in a second direction opposite to the first direction. The tailstock is moved in the first direction at a second speed lower than the first speed. When an input amount into the actuator becomes a value corresponding to the target pressing force while the tailstock is moving at the second speed, the tailstock is stopped.