Machine Tool Finishing Module With Feedback Feed Control

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Solution Overview

Problem

Existing fine machining techniques for cylindrical workpieces struggle with achieving high surface quality and dimensional accuracy, particularly in correcting shape errors like out-of-roundness, waviness, and conicity, while maintaining efficiency and minimizing tool load peaks.

Innovation Solution

A fine machining module integrated with a machine tool that uses a one-piece honing tool with a conical and shank section, featuring a linear drive and continuous regulation of the feed rate based on real-time force and torque measurements, allowing for precise correction of cylindrical workpiece surfaces without the need for measurement controllers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional honing processes are used with geometrically defined cutting edges, then machining speed is maintained, but surface quality and dimensional accuracy deteriorate due to form defects like out-of-roundness and waviness

Engineering Contradiction:
Improvesurface quality and dimensional accuracyVSAvoidmachining speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the fundamental parameter of the cutting edge from geometrically defined to geometrically undefined (abrasive particles). This parameter change enables the honing process to achieve high surface quality and dimensional accuracy while maintaining machining speed through the use of abrasive particles that can adapt to the workpiece surface geometry.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the traditional mechanical cutting edge with an abrasive-based system. Instead of using a rigid geometric cutting edge that creates form defects, the invention uses abrasive particles that can conform to the workpiece surface, eliminating the mechanical constraint that causes out-of-roundness and waviness while maintaining material removal efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If feed rate is increased to improve productivity, then processing speed increases, but load peaks increase causing dimensional scatter and quality deterioration

Engineering Contradiction:
Improveprocessing speedVSAvoiddimensional accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements feedback control by continuously monitoring the actual feed rate and comparing it with the target feed rate. When deviations are detected (such as load peaks causing dimensional scatter), the system adjusts the feed rate in real-time to maintain dimensional accuracy while maximizing productivity. This closed-loop control ensures that high processing speeds do not compromise quality.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If measurement controllers are added to improve dimensional accuracy, then manufacturing precision increases, but device complexity and cost increase

Engineering Contradiction:
Improvedimensional accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs self-service control where the system uses its own process data (actual feed rate, torque, power) to automatically adjust and optimize dimensional accuracy. Instead of adding external measurement controllers, the honing system itself generates the control signals needed to maintain precision, eliminating the need for separate measurement and control devices while achieving high dimensional accuracy of a few micrometers.

Inventive Principle:
Principle #25Self-service

4Manufacturing precision

If honing stones are pressed radially outward with high force to improve surface finish, then surface quality improves, but tool load peaks increase and processing efficiency decreases

Engineering Contradiction:
Improvesurface finish qualityVSAvoidtool load and energy consumption
Core Design Contradiction:
Manufacturing precisionVSPower

Solution Approach 1:

The patent changes the application method of abrasive action from high radial force pressing to a more controlled feed-based approach. Instead of continuously pressing honing stones radially outward with high force, the system uses controlled axial feed motion combined with rotational motion, achieving high surface finish quality with reduced peak loads and improved energy efficiency.

Inventive Principle:
Principle #35Parameter changes

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 approach enables high-quality machining with reduced scatter in dimensions, increased processing speed, and fewer load peaks, allowing for efficient correction of shape errors and achieving precise dimensional accuracy of a few micrometers without requiring frequent return strokes.

Implementation Method 1

a linear drive for moving the finishing tool in a feed direction parallel to the machining axis

Methodology Applied
Scientific EffectLinear motion:

Implementation Method 2

a rotary drive for rotating the workpiece around a machining axis

Methodology Applied
Scientific EffectRotational motion:

Implementation Method 3

The finishing tool is mounted on a slide in the area of its first tool end by means of a cardan bearing

Methodology Applied
Scientific EffectGimbal joint: Gimbal

Data Source

PatentEP3681674B1Finishing module for a machine tool and machine tool and machining method
Publication Date: 2023.05.31 MAS GMBH
  • EP3681674B1 patent drawingFigure 1
  • EP3681674B1 patent drawingFigure 2~4
  • EP3681674B1 patent drawingFigure 5~7

AI summary

A finishing module (50) for a machine tool (10), in particular a lathe, comprises: a module housing (52, 118), by means of which the finishing module (50) can be secured at a tool mounting position (78) of a machine tool (10); a linear drive (40) secured to the module housing (52) and designed to move a carriage (54) parallel to a machining longitudinal axis (18); a rotationally symmetrical finishing tool for finishing the interior and/or the exterior of a cylindrical workpiece surface (16) of a workpiece blank (14), the finishing tool (26) having a predefined axial tool length (L1 + L2) with a first tool end (30) and a second tool end (32) and the finishing tool (26) being mounted in the region of its first tool end (30) on the carriage. A tool guide (68) is formed on the module housing (52, 118) and the second tool end extends through said tool guide (32).