MikroMach

MobileMicromagneticMaterial Characterization

Micromagnetic TestingBasics (I)

alternating voltage

sensor element

component

Micromagnetism

- Cyclic magnetization

- Magnetic field at the surface is recorded using a small sensor element

Magnetic hysteresis loop

Micromagnetic effects

Conductivity, permeability

Micromagnetic TestingBasics (II)

microstructure

magnetizationmechanical

loads

with Bloch walls

interaction

with dislocations

interaction

HC-HC

-Br

virgin

hysteresisRemanence

B

Ht

Br

correlation

coerciveforce

micromagneticproperties

mechanicalproperties

Micromagnetic TestingBasics (III)

H

B

H

B

Magnetic Hysteresis

B

H

ΔH

ΔB

Barkhausen Noise Incremental Permeability

Upper Harmonics Analysis Eddy Current Analysis

Magnetic Hysteresis

Micromagnetic TestingCalibration (I)

MeasurementSignal (data)acquisition

Measured SignalsDescription of the magnetic properties

QuantitiesDescription of theacquired signals

Database of Quantitiesmeasured target

CalibrationRegression AnalysisPattern Recognition

Result

Calibration

(once per task)

Measurement

(repeated applicationof previous calibration)

Micromagnetic TestingCalibration (II)

Scope of Calibration

• Selection of significant quantities• Determination of the mathematical relation between measured and target

quantities• Suppression of disturbances through combination of several testing methods

Possible Target Values

• Hardness• Hardness depth (for case hardened and inductively hardened materials)• Residual stresses• Yield strength• Material

Micromagnetic TestingSensor Details

USB

Controller Board

Electromagnet

Sensor Element(spring-loaded)

Power Supply

Testing onCurved Surfaces

rmin = 30mmfor standard

series

Micromagnetic TestingSensor Design (I)

E1030 Series(standard size)

Micromagnetic TestingSensor Design (II)

Sensorfor Integral

MaterialCharacterization

PowerSupply

USB

Micromagnetic TestingSensor Design (III)

Examples ofApplication-Specific

MicromagneticSensor Designs

Micromagnetic TestingSoftware Environment

Modular Measuring System (MMS)

user access level

admin access level

Easy to use English or German UI Password protection Additional modules available

Micromagnetic TestingApplications (I)

Hardness Reference Blocks (HV 10)

hardness [HV 10] (ideal)ha

rdne

ss [H

V 1

0] (M

ikro

Mac

h)

Micromagnetic TestingApplications (II)

Rockwell Hardnessof Automotive Parts

Two materials in a single calibration

Each sample in this test was excluded from calibration at a time

hardness [HRC] (ideal)

hard

ness

[HR

C] (

Mik

roM

ach)

Material AMaterial B

Micromagnetic TestingApplications (III)

Residual Stresses

-600

-400

-200

0

200

400

600

800

-600 -400 -200 0 200 400 600 800resi

dual

stre

sses

[MP

a] (m

icro

mag

netic

)

magnetic field strength H

Barkhausen Noiseamplitude M

compressive

tensile

(-)HCM

MMAX

residual stresses [MPa] (X-ray)

Micromagnetic TestingApplications (IV)

Detection of Nitro Carburizationof Threaded Automotive Components

Barkhausen Noise profilesof 80 non-nitro carburized samples

Barkhausen Noise profilesof 28 nitro carburized samples

Micromagnetic TestingSummary

MikroMach – Micromagnetic Material Characterization in a Compact, Mobile Device

sensor = device

Hardness Hardness (case) depth Yield strength Residual stresses Nitride hardening state Materials recognition ...and many more

The modular software offers extended functionality and easy integration into external environment

Micromagnetic TestingMikroMach Specifications

Specifications

Magnetization frequency: 1 – 1,000Hz

Magnetic field amplitude: 1 – 200A/cm

Eddy Current frequencies: 1 – 15kHz (max. 24kHz)

Barkhausen Noise analysis range: 1 – 24kHz

Multi-frequency Eddy Current analysis: 8 frequencies

Multi-frequency Barkhausen Noise analysis: 8 frequency ranges

Evaluation of several noise maxima: yes

Acquisition speed (samples/sec @ 100Hz) max. 10, typical 2 - 3

Interface USB 1.1, upwards compatible

Typical delivery time is approximately 2-3 months for standard units

Custom sensor designs upon request