Stamping Process State Detection with Thermal Drift Compensation

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Solution Overview

Problem

The high variance in data collected from piezo sensors, temperature sensors, and rotary encoders during stamping processes limits the direct determination of stamping tool conditions, making it difficult to accurately assess the tool's state and predict maintenance needs.

Innovation Solution

A method involving data preparation steps such as removing commissioning data, interpolating data for uniformity, detecting and removing anomalies, and compensating for thermal interference to improve the determination of state variables, allowing for more precise assessment of the stamping process and tool condition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If data from piezo sensors, temperature sensors, and rotary encoders are collected during stamping processes, then the quantity of data is increased, but the measurement precision deteriorates due to high variance

Engineering Contradiction:
Improvedata quantityVSAvoidmeasurement precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing data preprocessing operations before actual analysis. Specifically, commissioning data is removed in advance, anomalies are detected and eliminated beforehand, and thermal interference is compensated for in advance. This preliminary preparation of the data set enables subsequent precise measurement of tool condition without the distorting effects of high variance, startup transients, or thermal drift.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and removes harmful components from the data set. Commissioning data is separated and eliminated because it contains startup transients that distort measurements. Anomalies are detected and extracted from the data stream. Thermal interference is identified and removed from the force and angle measurements. This extraction of harmful elements from the bulk data enables precise measurement of actual tool condition.

Inventive Principle:
Principle #2Taking out (Extraction)

2Temperature

If thermal interference is present in the data, then the temperature information is captured, but the determination precision of tool state deteriorates

Engineering Contradiction:
Improvetemperature measurementVSAvoidtool state determination precision
Core Design Contradiction:
TemperatureVSMeasurement precision

Solution Approach 1:

The patent converts the harmful thermal interference into a beneficial effect. Rather than simply discarding temperature data, the system uses the temperature measurements to calculate thermal compensation values. These compensation values are then applied to correct the force and angle measurements, transforming the previously harmful thermal drift into a useful correction mechanism. This enables precise tool state determination even in the presence of temperature variations.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Quantity of substance

If commissioning data is included in the analysis, then the complete operational data is available, but the state determination accuracy deteriorates due to startup transients

Engineering Contradiction:
Improvedata completenessVSAvoidstate determination accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent extracts and removes commissioning data from the complete data set. A start indicator detects when the press enters commissioning mode, and all data collected during this period is separated and eliminated before analysis. This extraction removes startup transients and initial thermal drift that would otherwise distort the tool state determination, while preserving the completeness of operational data for the actual production phase.

Inventive Principle:
Principle #2Taking out (Extraction)

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 improved determination of the stamping process state, optimizing maintenance intervals, reducing maintenance costs, and revealing wear behavior, facilitating deeper investigation into design weaknesses or errors.

Implementation Method 1

With the help of piezo sensors, temperature sensors and rotary encoders, status variables of a punching tool can be recorded. The structure-borne noise measurements show a strong temperature dependency.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

obtain third data indicative of a temperature of the punch tool over the plurality of periods

Methodology Applied
Scientific EffectThermal radiation detection: Thermal Radiation

Data Source

PatentEP4068019A1Device and method for processing the detected state variables of a punching process
Publication Date: 2022.10.05 LISA DRAXLMAIER GMBH
  • EP4068019A1 patent drawingFigure 1
  • EP4068019A1 patent drawingFigure 2a~2c
  • EP4068019A1 patent drawingFigure 3a~3c

AI summary

The invention relates to a device for determining the state of a stamping process, configured to obtain first data, second data, and third data; to remove start-up data from the first and second data, which were acquired during periods of commissioning the stamping tool; to interpolate the first and second data to obtain a uniform length and step size of the second data relative to the first data for the majority of periods of the stamping process; to detect and remove anomalies in the first and second data; to determine and compensate for a thermal disturbance of the third data on the first and second data; and to determine the state of the stamping process based on the first and second data compensated for the thermal disturbance.