Introduction spot- and projection weld inspection with the Mini Scanner A high level inspection...

Introductionspot- and projection weld

inspectionwith the

Mini Scanner A high level inspection method with a handy instrument

AMSTERDAM

TECHNOLOGYNDT Scan Solutions

Raised in 2006 by:

• vAmsterdam SES Software, Engineering and Systems for ultrasonic and Eddy Current inspection machines

• Technolothgy BVEngineering of special machines and instruments for Non Destructive Technology

AMSTERDAM

TECHNOLOGY

Overview of build immersion tank based inspection machines

Ultrasonic

Immersion tank scanners

•High resolution•Complex shapedproducts •Focused transducers

Ultrasonic immersion tank scannerA high quality inspection method

Practical inconveniences •Static position: The samples have to be transported to the scanner•The samples have to drown into the water •Limited tank dimensions•Time-consuming positioning of parts in the tank•Long inspection times•High investments

Project with DaimlerChrysler

Project description:

Design a portable ultrasonic scanner for spot weld inspection on location.

Specifications:•Short inspection time•No immersion of the inspected parts•High resolution C-scan presentation •For plate thickness from 0,5 mm•Handheld instrument

Mini Scanner

A miniature “immersion tank” scanner.

The scanner head is filled with water and is sealed with a membrane.

Gel is used as an ultrasonic couplant.

•Scan area: 10 x 20 mm•Resolution: 0,1 x 0,1 mm•Scan time: < 5 seconds

Diagram spot weld testing with the Mini Scanner

Water

chamber

Mini

Scanner

Moving ultrasonic

transducer

IE=Interface Echo

Couplant

( gel )

The C-scan is picture, composed by the 100 x 200 colored pixels as generated in each scan point.

Yellow gate; In this area the maximum amplitude of the ultrasonic signal is measured

A-scan

presentation

C-scan presentation

IE BEWE

WE=Weld EchoBE=Back Wall Echo

Red gate; sets the start position of the yellow gate

A color related to the value of the maximal amplitude in the yellow gate, is set as a pixel in the C-scan for each scan point.

® Patent pending / all rights by Amsterdam Technology bv

Scanning method

•Focused ultrasonic transducer moves in a water filled compartment in the scanner head•35MHz ultrasonic transducer•Diameter focus point < 0,1mm•Membrane sealed water chamber•Spiral shaped scanning pattern•High scanning speed •Gel as ultrasonic couplant

® Patent pending

Exchangeable

scan heads

Straight scan head for perpendicular scanner position.

Mirror based scan head for angles scanner position.

Used for difficult to reached spot weld position

Mini Scanner System

Scanner with control unit

•PC platform•Windows XP•Touch Screen•USB data exchange

Spot weld testHigh tension steel plate

A-scan on cursor position- besides the weld -

In the yellow gate: back wall echo of the first plate

Plate thickness first plate

Test parameters:

•Shape of the spot weld nugget

•Shape of the pore

Spot weld testHigh tension steel plate

A-scan on cursor position- in the nugget -

Thickness

In the yellow gate: No weld echo (good welded in that position)

In green gate: Back wall echo of the spot weld

Test parameter:

•Thickness of the spot weld

Spot weld testHigh tension steel plate

A-scan on cursor position-On the edge of a

pore in the weld -

Depth of the pore in the spot weld

In the yellow gate: Echo of a pore

Test parameters:

•Size of the pore

•Depth of the pore

Spot weld testHigh tension steel plate

Measuring dimensions:

•Size of the nugget

By drawing an ellipse around the contour the dimension is calculated

Cursor controlled dimension measurement in C-scan.

Spot weld testHigh tension steel plate

Reference: A-scan of position beside the spot weld.

Time Of Flight (TOF)

Inde

ntat

ion

Tim

e O

f F

light

Test parameters:

•Indentation measurement by Time Of Flight (TOF)

Arplas weldSteel plate

A-scan on cursor position- besides the weld -

In the yellow gate: back wall echo of the first plate

Plate thickness first plate

Test parameters:

•Shape of the Arplas weld

Arplas weldSteel plate

A-scan on cursor position- on the weld -

Thickness weld

In the yellow gate: No weld echo (good welded in that position)

In green gate: Back wall echo of the spot weld

Test parameter:

•Thickness of the Arplas weld

Arplas weldSteel plate

A-scan on cursor position- on the edge of the weld -

In the yellow gate: 90% weld echo

(green-red colored pixel, on the edge of the weld)

Test parameter:

•Detail of the Arplas weld

•Detecting dimensions

(By moving the cursor)

1,05

7,20

Software

•Storage of A-scans (ultrasonic signal) for each scanning point•After event data evaluation possible by gate repositioning•Ultrasonic settings storable as pre-set for typical applications•Numerical wall thickness indication•Direct C-scan presentation•Two C-scan presentations with independent gate settings•No picture processing for C-scan presentation

Application: Nut welding

Welded nut (round) Welded nut (square)

-- The Mini Scanner was placed on the flat plate side --

Application: laser welding

Laser weld round (Alu plate) Laser weld round (Alu plate)

-- The Mini Scanner was placed on the flat plate side --

Application: Rivet inspection

Rivet in gearbox part

.

-- The Mini Scanner could be placed on both sides of the part --

Application: Porosity check HP casting

A-scan beside a pore A-scan on a pore

High pressure cast aluminum 2.0 mm thickness

Since the mini scanner is used in the field a lot of new applications are coming up.

Inspection with the Mini Scanner

Applications• Multiple plate weld inspection• Plate thickness 0,5 -8 mm with standard transducers.• Weld between plates and massive parts

Conditions:• Scan head has to be placed on a flat surface• Accessibility scanner to the product• Use of gel allowable

Practical limitations

Even the mini scanner is subject to the physical limitations caused by the properties of ultrasonic pulse echo techniques, such as:

•Insufficient reflection of the ultrasonic echo’s

Caused by:•Disturbance by sharp edges around the weld•Raw or dirty surface•Scanner not good in position during scanning

Latest developments

Smaller model scan unit

Lower weight: -40 %

Reduced scan time: -20%

Concluding

•Handy ultrasonic C-scan device for detailed weld inspection•Multiple ultrasonic signal evaluation modes•Storage of all ultrasonic data•Improved welding process control possible by inspection on location