Internal Milling Machine Layout for Stable Low-Height Machining

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Solution Overview

Problem

Existing rotary-milling machines for machining shafts, particularly crankshafts, face challenges in achieving high stability and manufacturing accuracy due to inadequate support and accessibility, especially when using internal milling cutters, which can lead to reduced machining precision and increased machine height.

Innovation Solution

A rotary-milling machine design featuring a bridge-shaped Z-slide with a portal carriage, allowing the internal milling cutter to be mounted rotatably between transverse guides, and an inclined bed with a chip conveyor system that minimizes machine height while maintaining stability and accessibility, ensuring precise machining and efficient chip removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the support for the milling unit is arranged laterally offset parallel to the headstock on separate Z-guides, then the machine structure is simplified and accessibility is improved, but the stability of the machine deteriorates

Engineering Contradiction:
ImproveaccessibilityVSAvoidmachine stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent combines the Z-guides for the headstock and the milling unit support onto a single common Z-guide structure. This merging of previously separate guidance systems into one integrated structure maintains machine stability while preserving accessibility, as the unified guide allows proper positioning of both components without requiring lateral offset arrangements.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If the machine bed is designed as an inclined bed with mounting surface sloping from back to front, then chip removal efficiency is improved and accessibility is enhanced, but the machine height increases

Engineering Contradiction:
Improvechip removal efficiencyVSAvoidmachine height
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The patent addresses the height increase from bed inclination by optimizing the spatial arrangement of components in the vertical dimension. The inclined bed design is maintained for chip removal efficiency, but the overall machine height is controlled through careful positioning of the headstock, milling unit, and other components to minimize the vertical envelope while preserving the functional benefits of the inclination.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the Z-slide with tool unit is moved transversely to locate largely outside the headstock area, then tool change accessibility is improved, but the machine structure becomes more complex

Engineering Contradiction:
Improvetool change accessibilityVSAvoidmachine structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent employs dynamic positioning capabilities where the Z-slide with tool unit can be moved transversely to positions largely outside the headstock area during tool changes, but returns to its working position during machining operations. This dynamic repositioning provides excellent tool change accessibility without requiring permanent structural modifications that would increase machine complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3493935B1Internal milling machine
Publication Date: 2024.12.18 MAG IAS GMBH
  • EP3493935B1 patent drawingFigure 1a
  • EP3493935B1 patent drawingFigure 1b
  • EP3493935B1 patent drawingFigure 1b1

AI summary

The invention relates to an internal milling machine for milling a workpiece that rotates during the machining, comprising an annular internal miller (5), wherein the Z-slide (4a, b) of each tool support (3a, b) comprises a through-opening, and the cross slide (7) carrying the internal miller (5) can be moved in the X-direction, the direction of extension of the assembly surface (1a) of the bed (1), which is designed such that it slopes forward. This main structure and particularly the arrangement of the Z-guides (6a, b) for the at least one tool support (3, b), outside the Z-guides (16a, b) for the counter spindle head (2') enables favourable centre-of-gravity positions particularly of the movable components and a high stability of the machine and consequently a high machining precision of the machine.