Rotating Workpiece Table Machining With Holder Shift Control

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Solution Overview

Problem

Machining operations, particularly in metalwork, face inefficiencies in productivity and processing time due to limitations in tool positioning and workpiece rotation, leading to suboptimal machining conditions.

Innovation Solution

An operating method that maintains a minimum speed of the tool relative to the workpiece by shifting the workpiece holder to ensure a constant distance from the axis of rotation, allowing for continuous processing with optimal speed and positioning, and optionally using multiple tools to distribute loads and improve productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the workpiece is processed by milling, then flexibility in machining is improved, but processing time increases significantly

Engineering Contradiction:
Improvemachining flexibilityVSAvoidprocessing time
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The workpiece is rotated during machining instead of keeping it stationary, transforming the machining process from static milling to dynamic turning. This allows the cutting tool to engage the workpiece in a continuously moving state, significantly reducing processing time while maintaining machining flexibility through programmable rotation speeds and tool paths

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the fundamental machining parameter from stationary cutting (milling) to rotating workpiece cutting (turning). By controlling the rotation speed of the workpiece table and the feed rate of the cutting tool, the process achieves both high productivity and adaptability for different workpiece geometries

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the workpiece table rotates quickly to improve productivity, then processing speed increases, but tool imbalances occur

Engineering Contradiction:
Improveprocessing speedVSAvoidtool balance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A counterweight is attached to the workpiece table at a position opposite to the workpiece holder, creating a balancing force that counteracts the centrifugal force generated by the rotating workpiece. This prevents tool imbalances and vibrations even at high rotation speeds, maintaining both productivity and reliability

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The balancing mechanism is applied locally at the workpiece table rather than requiring balanced tools throughout the entire system. The counterweight compensates for the specific imbalance caused by the workpiece holder position, allowing high-speed rotation without compromising tool balance

Inventive Principle:
Principle #3Local quality

3Productivity

If the cutting tool is positioned close to the axis of rotation to reduce tool distance, then machining efficiency improves, but the minimum distance requirement cannot be maintained

Engineering Contradiction:
Improvemachining efficiencyVSAvoidminimum tool distance
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The workpiece is pre-positioned on the workpiece table at an optimized location before rotation begins. This preliminary positioning ensures that during rotation, the cutting tool maintains the required minimum distance from the axis of rotation while still achieving efficient machining through proper selection of rotation speed and tool feed rate

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3684533B1Turning of workpieces on a machine tool
Publication Date: 2021.11.24 SIEMENS AG
  • EP3684533B1 patent drawingFigure 1~2
  • EP3684533B1 patent drawingFigure 3~4
  • EP3684533B1 patent drawingFigure 5~6

AI summary

A machine tool has at least one workpiece table (1), a workpiece holder (2) situated on the workpiece table (1), and a tool (5). The workpiece table (1) can be rotated about a rotation axis (7) in a position-controlled manner, and the tool (5) can be moved at least parallel to the rotation axis (7) in a position-controlled manner. A workpiece (3) is clamped into the workpiece holder (2). The workpiece table (1) is rotated about the rotation axis (7) by a plurality of complete revolutions. While the workpiece table (1) is rotated about the rotation axis (7), the tool (5) is placed at least temporarily against the workpiece (3) on a side substantially facing away from the workpiece table (1), so that the tool (5) machines the workpiece (3). Throughout the machining of the workpiece (3) by means of the tool (5), the tool (5) is at a distance (al) from the rotation axis (7), said distance always being at least equal to a predefined minimum distance (amini). The first workpiece holder (2) is displaced on the workpiece table (1) in a position-controlled manner during the machining of the first workpiece (3) by means of the first tool (5). A direction in which the displacement takes place has a component towards or away from the rotation axis (7).