Toolpath Radius Compensation for Uniform Machined Contours

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Solution Overview

Problem

Existing machining methods using machine tools with tools of finite radii cannot produce workpiece contours with sharp edges or strong curvatures without errors, leading to deviations between target and actual contours, especially when different tools are used, resulting in non-identical workpieces.

Innovation Solution

A method and control device that generate a new target contour incorporating deviation contours to account for tool radii, allowing identical workpieces to be produced using tools with different effective radii by determining new toolpaths based on the tool effective radii, and a control function to preprocess part programs for synchronized machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If tool radius correction is applied by the control system to account for actual tool radius, then the toolpath is adjusted for the current tool radius, but workpieces machined with different tools differ particularly in the area of edges or highly curved surfaces

Engineering Contradiction:
Improvetool radius correction accuracyVSAvoidworkpiece contour uniformity
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing deviation contours for different tool radii before machining. The control system determines the actual tool radius, selects the appropriate deviation contour from memory, and applies it to generate the corrected toolpath. This preliminary preparation of deviation data eliminates the need for real-time complex calculations during machining, ensuring consistent workpiece contours across different tools.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating and storing reference deviation contours in the control system's memory. These deviation contours represent the difference between target and actual contours for various tool radii. During machining, the appropriate stored deviation contour is copied and applied to the current toolpath, ensuring that workpieces machined with different tools of the same type produce identical contours.

Inventive Principle:
Principle #26Copying

2Productivity

If different tools with varying radii are used to machine workpieces, then tool availability and productivity are improved, but deviations between manufactured workpieces occur

Engineering Contradiction:
Improvetool availabilityVSAvoidworkpiece uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the toolpath parameters based on the actual tool radius. The control system determines the actual radius of the used tool, selects or calculates the corresponding deviation contour, and modifies the toolpath parameters accordingly. This allows different tools with varying radii to produce identical workpiece contours, maintaining manufacturing precision while improving productivity through tool flexibility.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If standard tool radius is used for all tools, then toolpath calculation is simplified, but tools with wear or different dimensions cannot produce identical workpieces

Engineering Contradiction:
Improvetoolpath calculation complexityVSAvoidworkpiece consistency
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing deviation contours for various tool radii in the control system's memory. Instead of performing complex real-time calculations during machining, the system has these deviation data ready in advance. When a tool is used, the appropriate pre-calculated deviation contour is selected and applied, simplifying the real-time processing while ensuring accurate workpiece consistency.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4703821A1Method of making uniform workpieces
Publication Date: 2026.03.04 SIEMENS AG
  • EP4703821A1 patent drawingFigure 1
  • EP4703821A1 patent drawingFigure 2
  • EP4703821A1 patent drawingFigure 3

AI summary

The invention relates to a method for machining at least one first workpiece (5A) using a first tool (3A) with a first tool radius (RA) and a second workpiece (5B) using a second tool (3B) with a second tool radius (RB), wherein a target contour (S) for the workpieces (5A, 5B) is specified, wherein a first toolpath (TA) for the first tool (3A) is determined as a function of the first tool radius (RA), wherein, due to a curvature or an edge in the target contour (S), the target contour (S) cannot be produced flawlessly with the first tool (3A) due to the first tool radius (RA), but only in the form of a first actual contour (IA), which in the area of ​​the curvature or the edge comprises a first deviation contour (AA) compared to the target contour (S).The object of the invention is to produce largely identical workpieces using different tools that differ in their tool radius. To this end, the invention provides that a new target contour (NS) is generated, which includes the deviation contour (AA), wherein a new second toolpath (TB') for the second tool (3B) is determined as a function of the second tool radius (RB) to generate the new target contour (NS), and the second workpiece (3B) is machined according to the new second toolpath (TB').