ct in dimensional metrology , engineering and - ku leuven

CT in Dimensional Metrology ,

Engineering and Manufacture

CT in Production Quality Control - Leuven, June 4, 2013

Prof. Dr. Ir. Jean-Pierre KRUTH

Katholieke Universiteit Leuven (K.U.Leuven)Mechanical Engineering Dept.

Division PMA (Production engineering, Machine design & Automation)

Belgium

[email protected]

http://www.mech.kuleuven.be/pma/

Evolution in 3D measuring devices

2005

CT scanner for dimensional metrology

X-ray CT Metrology for Engineering and Manufacture

1970

1980

Common 3D dimensional metrology equipment

CT scanner for material investigations

Medical CT scanner

Cartesian 3D-CMM Articulated measuring arm

Tactile probe Laser probe

CT-based equipment

Industrial demand for 3D CT measurement

• Part complexity increases as a result of more complex design, higher function

integration and new production technologies:

– Hollow hydroformed camshafts or hollow constructed crankshafts (Dr. A. Sterning)

– Additive manufactured components (LayerWise Inc.)


– 2K injection molding, plastic connectors with metal inserts

200 mm

Difference between medical and industrial CT

Main differences of industrial CT:

• X-ray source and detector do not rotate

• Object rotates (patient does not)

• Rotational axis vertical rather than horizontal

• 2D flat panel detector or 1D linear detector

• Higher power (200 KeV, 450 KeV, 15 MeV)

• Should provide traceable measurements for

dimensional quality control

MedicalIndustrial


X-ray source X-ray detectorObject

Difference between medical and industrial CT

Courtesy Metris

(Nikon Metrology)

Main differences of industrial CT:

• X-ray source and detector do not rotate

• Object rotates (patient does not)

• Rotational axis vertical rather than horizontal

• 2D flat panel detector or 1D linear detector

• Higher power (200 KeV, 450 KeV, 15 MeV)

• Should provide traceable measurements for

dimensional quality control


1D line detector 2D flat panel detectorCourtesy GE-Phoenix

Workflow in dimensional CT measurement

CT scan

Data Processing

3D Reconstruction

(CT Pro)

Object

2D X-ray images

3D grey voxel model


Data Analysis

Dimensional measurement

(VolumeGraphics)

Thresholding

Edge detection

(VolumeGraphics)

Surface modelDimensions

CT metrology: no resolution, but accuracy

- Medical and material applications are satisfied with resolution

- Dimensional metrology requires accuracy and traceability to the unit of length

(the meter)

Required accuracy:

- Medical and material applications: none or 10-1-10-2 (1..5%)

- Dimensional metrology: CMM 10-5-10-6 (laserinterferometry 10-7-10-8)


X-ray image with Nanotech™ transmission target Electron microscopy image of test pattern

5µm

1µm1µm

Outer bar width = 5 µmInner bar width = 1 µmThickness 1 µm goldImage at 80kV

5µm

Projections taken from 4 orientations Reconstruction by backward projection

Principle of CT reconstruction: multimaterial


(Grey scale: grey →→→→ red →→→→ blue →→→→ purple)

• Source current

• Source voltage

• Target material (spectrum)

• Beam filter(material & thickness)

• Number of poses

• Exposure time

Adjustable parameters in CT registration

Same spectrum – Higher intensity

1000µA

500µA

50


• Exposure time

• Averaging images

• Edge detection (thresholding)

• Beam hardening and other algorithms

• Part orientation (w.r.t. slantness)

• Etc.

Larger spectrum – Higher intensity

50 100

50

Edge detection

Where is the edge of the material or part?

Problem: there is a gradual transition of gray values at the edge

Solution: complex edge detection algorithms


• Maximum penetration at 420 keV:� 70 mm Fe

� 200 mm Al

Maximum allowable material penetration

• Avoid thick parts


• Avoid thick parts

• Avoid slant parts

• giving total extinction along

its long side• giving over-expore along its

short side

• Proper part orientation may resolve problem

Applications of CT in engineering & mfg.

• Applications of CT technology in engineering

Internal shapes/geometries and (multi-material) assemblies

– Design

• Engineering and reverse engineering

• Mechanisms and assemblies


– Manufacturing

• Dimensional Metrology / Precision / Quality Control

– Additive Manufacturing (Rapid Prototyping & Manufacturing)

– Internal and external geometry

– Assemblies and multi-material components

– Accuracy, calibration and traceability

• Combined dimensional and material quality control

Case 1: Reverse Engineering and CAE of cylinder head

• Scanning cylinder head on 10 MeV CT machine + 2D reconstruction• 3D reconstruction + STL meshing

• Segmentation of different materials and internal structure• Re-meshing for FEM and CFD (Computational Fluid Dynamics)

• CFD calculation (Star-CD®)

• (Re)design using STL-based CAD systems (Materialise 3-matic®)

Engineering and reverse engineering: case 1

}(Materialise Mimics®)


Data: courtesy of BRP-Rotax GmbH & Co. KG.

Processing: courtesy of Materialise N.V., Belgium

• Slices through the 3D reconstructed CT model

• All internal structures are revealed

• Material differentiation based on density– Aluminium

– Steel inserts


Data: courtesy of BRP-Rotax GmbH & Co. KG.

Processing: courtesy of Materialise N.V., Belgium


Image processing using Mimics® software of Materialise



Extraction of water jacket from cylinder headOperations done on STL faceted model (STL mesh)



Courtesy of Materialise N.V., Belgium

Re-meshing the water jacket

• Original skew triangle mesh is transformed in an equilateral triangle mesh, optimized for CFD analysis



Thickness analysis and local mesh refining• Wall thickness analysis: detect and visualize thin structures

• Local mesh refining in thin sections to ensure optimal results during CFD analysis


X-ray CT Metrology for Engineering and ManufactureData Courtesy of BRP-Rotax GmbH & Co. KG.

Courtesy of Materialise N.V., Belgium

Results of CFD*calculationsand temperature profile



profilecomputed in Star-CD®

Courtesy of Materialise N.V. and Star-CD

* Computational Fluid Dynamics

Case 2: Design and manufacturing of scaffold structures

Medical scaffolds = porous implants for bone regenerationPurpose: production of scaffolds with regular porous structures

• Manufacturing by additive manufacturing (SLS/SLM) from Ti powder

• Analysis of achievable pore and beam sizes by SLS/SLM (CT metrology)• Analysis of strength and failure mechanism of scaffold (CT with in-situ loading)

• Own-made in-situ uniaxial loading bench in CT device.



• Design of regular porous structure for Ti scaffold



Unit cell Design Ti6Al4V scaffold

• CT measurement of pore and beam size– Proved reproducibility of additive manufacturing

process


Micro-CT imaging

0% strain 5% compression


scaffold (n=5) PO 1.00

Average beam size (µm) 187 ± 5

Average pore size (µm) 620.55 ± 2.91

Global porosity (%) 81.05 ± 0.51

Interconnectivity (%) 100


– using CT with in-situ loading bench

• Analysis of strength and failure mechanism


Development: G. Kerckhofs, K.U.Leuven-MTM


– using CT with in-situ loading bench

• Analysis of strength and failure mechanism


Pores: 0.8 1.2 mm

• Testing and calculating strength (yield, UTS) and Young modulus (E)

• Comparison of deformed and un-deformed CT images to calculate strain• Comparison/mapping to FEM calculation (validation)


Strain (-)

Stress (MPa)


• Calculation of strength (yield, UTS) and Young modulus (E)

• Comparison of deformed and un-deformed CT images to calculate strain• Comparision/mapping to FEM calculation


CT measured strains FEM predicted strains


Overview of presentation



– Design




– Manufacturing







Mechanism and assembly: watches


Courtesy Metris N.V., Belgium

(Nikon Metrology N.V.)

Monitoring operation of mechanism

Mechanism and assembly: watches




Mechanism and assembly: gear box




Assembly (mechanic + electronic): camera

Complex assembly of mechanical, optical and electronic components (PCB, leads, wires, soldering spots,…)

X-ray CT Metrology for Engineering and Manufacture32






– Design




– Manufacturing







Additive manufacturing: SLS/SLM example

laser

Polymer

Metal (Steel)


Composite (Cermet-HM)

Metal (Ti)

Ceramic (Al2O3)

Inlet duct in stainless steel (ILT)

Injection mould with conformal cooling (KUL-DNI)

Dimensional metrology: Examples of AM parts

Collimator for space device with cooling (CSL)


Air ducts in nylon (Boeing)

Part with conformal cooling channels(LayerWise-KUL)

Heat exchanger for satellite (Verhaert/QinetiQ Space)

Dimensional metrology: AM cases - parts with holes

CT measurement of AM/SLM steel part with conformal cooling


CT measurement of AM/SLM parts (steel and aluminum) to check smallest possible hole diameter

Block (80x8x8 mm) with holes (0.4mm to 4 mm)

• Non-destructive and contactless measurement

• Check of internal geometry of conformal cooling channels in nozzle

• CAD compare: comparision of actual dimensions with CAD model (Ist vs. Soll)

CAD model of

nozzle with

conformal

cooling channels

Dimensional metrology: AM cases – nozzle with cooling


cooling channels

Real geometry

(Cut model)

Results of

CT-scan

Comparison with

CAD model

3D CT reconstruction

Dimensional metrology: Case 2 – Diesel injector

Diesel injectorCourtesy Metris N.V., Belgium


2D X-ray image

Injector 3D CT reconstruction

Feature extraction and measurement (e.g. diameter and position of holes)

Cut through inlet holes of injector


Diesel injector


CAD Compare: Soll vs. Ist values


Diesel injector


Error / mm

External geometry

CAD Compare: Soll vs. Ist values

Error / mm

Internal geometry

Diesel injector



Dimensional metrology: Case 3 – Audi inlet fan

Audi Inlet Fan – CT model


Audi Inlet Fan – CAD compare (Soll vs. Ist)




CAD compare (Soll vs. Ist) Wall thickness

Dimensional Quality Control



Simultanuous• Material• DimensionalQuality Control


Air inclusionsSize deviations

“The heart of the car, if it stops the car stops”

Honda Hydraulic manifold

Dimensional metrology: Case 4 – Honda Hydraulic manifold




External geometry Internal geometry : cut

Honda Hydraulic manifold



CT model CT modelCAD compare CAD compare



Measured (external)dimensions



Measured (internal) dimensions

Dimensional metrology: Case 5 – Metal screws


Part 1 Part 2Material: Steel (42CrMo4 or 1.72) Material: Aluminum (EN AW-7075)Dimensions: ~ Ø12 x 30 mm Dimensions: ~ Ø32 x 24 mmMeasurement time: 6 min. (720 projections)

Measurement time: 6 min. (720 projections)


Measure cylinder

Measure plane


Measure pitch

Measure angle

Measure length

Measure cylinder

Measure plane

Measure distance plane-plane




– Design




– Manufacturing







Dimensional measurement of assemblies

• CT-scanning of assembled components:the only way to measure components in the assembled state





– Design




– Manufacturing







Dimensional quality control

Material quality control

Dimensional & material QC: Case 1 – Car inlet fan


Porosity

Dimensional & material QC: Case 2 – Turbine blade

Measuring:

• Dimensions

– Wall thickness

– Cooling holes

• Material quality

– Pores

– Corrosion


2D CT-scan3D: volumeCourtesy Metris N.V., Belgium


Special blade inspection system with 450kV

Dimensional & material QC: Case 2 – Turbine blade


RED – outside tolerance

system with 450kV

Scatter Free Radiography (method)

Method:

Turbine blade scanned through a collimated fan

beam to produce scatter free 2D image.

2D flat panel detector


Side View

1D linear detector

Source & spot(450 kV micofocus)

Collimating plates

Part moving up

Reconstruction progressing downward

Flat fan beam

Automatic measurement (data display)


Automatic wall / webthickness measurement

Automatic measurement (results database)


Dimensional & material QC: Case 3 – Sandwich panel

Case 3: Lightweight sandwich panel

Production Quality Control:

• Check wall thickness (Dimensional Quality Control)

• Check weld quality (Material Quality Control)



Case 3: Lightweight sandwich panel

Continuous production method:

• Thermoforming flat polymer foil• Folding to create honeycomb• Welding folds and top + bottom foils


Wall thickness measurementusing Volume Graphics software

3D plot

CT parameters:

• Voltage: 65 to 75 kV

• Current: 350 & 470 µA

• Magnification: ±200

• Filter: No


2D plot


Section plane

Section

Weld spot

• Wall thickness analysis (Software: Volume Graphics)



Minimal/Maximal wall thickness


Wall thickness analysis using Volume Graphics Software®


• Weld analysis: density plot


Weld spot


• Weld analysis in logitudinal direction

Density plot (material QC) Thickness plot (dimensional QC)



Dimensional & material QC: Multimaterial/Assemblies

Case 4: Light bulbs

Production Quality Control:• Positioning electrodes

• Glass welds

• Assembly

• Materials defects



Case 4: Light bulbs


• Glass welds

• Assembly


Assembly


Weld control


Case 4: Light bulbs


• Glass welds

• Assembly



Weld control

Thank you for your attention




ct in dimensional metrology , engineering and - ku leuven

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