Rotary Press Punch Wear Evaluation Using Image Processing

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Solution Overview

Problem

Current methods for evaluating the condition of press punches in rotary presses are imprecise and costly, particularly in assessing wear on punch tips, which can lead to unacceptable compact specifications and production issues due to the difficulty in monitoring wear and damage in real-time.

Innovation Solution

A method using a camera to record images of the press punch, processed by an evaluation device with image processing algorithms, allowing for reliable and cost-effective condition analysis, including wear detection and issuing warnings when parameters exceed permissible ranges, enabling automatic and independent evaluation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual inspection methods are used to assess press die condition, then operator dependency and subjectivity are reduced, but measurement precision and reliability remain insufficient

Engineering Contradiction:
Improvecondition assessment precisionVSAvoidinspection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual visual inspection with an automated optical measurement system using a camera and image processing algorithms. This substitutes human sensory evaluation with mechanical/optical measurement devices, achieving objective, quantifiable assessment of press die wear and damage conditions without requiring operator expertise or subjective judgment.

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

Solution Approach 2:

The patent creates a digital copy (image) of the press die surface and analyzes this copy through image processing algorithms. Instead of directly measuring the physical die with complex tactile sensors, the system captures optical information and processes it computationally, simplifying the physical measurement apparatus while maintaining assessment accuracy.

Inventive Principle:
Principle #26Copying

2Productivity

If manual inspection methods are used, then device complexity is low, but productivity and real-time monitoring capability deteriorate

Engineering Contradiction:
Improveinspection speedVSAvoidinspection system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The inspection system performs self-assessment by automatically capturing images and processing them through algorithms that detect wear and damage patterns. The system serves itself by requiring minimal human intervention - operators simply need to load the press die into the measurement device, after which the automated system completes the entire inspection and evaluation process independently.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces time-consuming manual inspection processes with automated optical capture and computational analysis. The camera rapidly captures die surface images, and image processing algorithms automatically analyze wear patterns, eliminating the need for operators to manually examine each die component, thereby dramatically increasing inspection throughput.

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

3Measurement precision

If LED micrometer and laser sensor scanning is used, then measurement precision improves, but device complexity and cost increase significantly

Engineering Contradiction:
Improvegeometric parameter measurement precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of using complex tactile measurement devices like LED micrometers and laser sensors that physically contact or closely approach the die surface, the patent uses optical imaging to create a visual copy of the die surface. This optical copy is then analyzed through image processing, achieving sufficient measurement precision for wear detection without requiring complex mechanical measurement apparatus.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent employs a relatively simple and inexpensive camera system instead of expensive precision measurement sensors. While the camera may have lower absolute measurement resolution compared to laser scanners, it provides sufficient precision for detecting wear patterns and damage on press dies, and the lower cost and complexity make the system more practical for industrial deployment.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If press force curves are used to analyze punch head wear, then wear detection capability improves, but the ability to detect punch tip wear deteriorates

Engineering Contradiction:
Improvepunch head wear detection reliabilityVSAvoidpunch tip wear measurement precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies different evaluation methods to different segments or regions of the press ram. Press force curves are used to assess wear on the punch head (upper portion), while optical image processing specifically targets the punch tip (lower portion). This segmented approach allows each region to be evaluated by the most appropriate method, achieving comprehensive wear detection across the entire press ram assembly.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4439453A1Method and device for evaluating the state of a press punch
Publication Date: 2024.10.02 FETTE COMPACTING GMBH
  • EP4439453A1 patent drawingFigure 1~4
  • EP4439453A1 patent drawingFigure 5~7
  • EP4439453A1 patent drawingFigure 8~9

AI summary

The invention relates to a method for evaluating the condition of a press ram of a rotary press, wherein the press ram has a ram shaft (10) at one end of which a ram head (12) interacts with a pressure device of the rotary press during operation and at the other end of which a ram tip (14) is arranged, which compresses a material in a cavity of a die disc of the rotary press into a compact during operation, wherein the method comprises the following steps: • an image of at least one section of the press ram is taken with a camera (22), • the taken image is supplied to an evaluation device (26), • the evaluation device performs a condition analysis of at least one section of the press ram using an image processing algorithm and evaluates the condition of the press ram on the basis of the condition analysis.• If the condition of the press ram, as evaluated by the evaluation unit, lies outside a permissible range, the evaluation unit issues a warning message. The invention also relates to a device for carrying out the method.