NDT Standards for Additive Manufacturing

Transcription

1 NDT Standards for Additive Manufacturing Ben Dutton Mohd Hashimi Rosli David Ross-Pinnock Workshop on Additive Manufacturing (WAM 2018) PMO-003-F7(v2) Grenoble, France 9th - 10th April 2018

2 Overview The MTC Background Scope of the standard Work completed to date Summary

3 High Value Manufacturing Catapult AFRC Advanced Forming Research Centre CPI Centre for Process Innovation 550 employees >50 engineers focussed on AM projects MTC also hosts the European Space Agency (ESA) AM Benchmarking Centre since May 2017 NAMRC Nuclear Advanced Manufacturing Research Centre AMRC Advanced Manufacturing Research Centre NCC The National Composites Centre MTC Manufacturing Technology Centre WMG Warwick Manufacturing Group

4 Catapult Aim: Bridge the Valley of Death

5 MTC MEMBERS TIER 3 TIER 1 TIER 2 Over 110 members but we work with companies

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7 Background Complex shapes Rough surfaces Part courtesy of 3T RPD Ltd: Additive manufacturing causes inspection/ndt challenges due to inherent freedom to manufacture: complex shapes rough surface finish Some of the sectors that need NDT standards are: Aerospace Automotive Medical Part courtesy of MTC s National Centre for NS & AM There are a number of international efforts to produce such standards and progress of some of these is presented here.

8 Background AM offers many design opportunities, but presents many inspection challenges. NDT of AM parts is vital to ensure: Safety; Performance; Reliability; Process confidence. A range of defects can occur - some of which are unique to AM. Inspection is challenging due to complex geometries and accessibility of features. Artefacts can be designed and built in different materials to test NDT technologies. Standards are urgently required for industry to confidently adopt AM processes.

9 Background Project Timeline EU FP7 AMAZE Project CRP NDT Standard for AM (Phase 1) GE Power Triaging through NDT (NATEP) CRP NoSFAM (Phase 2) Various projects have been carried out by the MTC, and in collaboration with others, to define standards for NDT in AM since 2015.

10 Background Project Timeline Supporting project EU FP7 - AMAZE CRP NDT Standard for Additive Manufacturing - Phase 1 GE- Power AMAZE Triaging through NDT (NATEP) CRP Phase 2 (NoSFAM) MTC internal project Industrial partners volunteer to build artefacts using different materials. NDT partners volunteer to trial built artefacts. Feedback from AM manufacturer and NDT partners. Task To rapidly produce large defect-free additivelymanufactur ed components. Create defects library based on information from AMAZE Review existing standards Create standard artefact design Refine design of artefact Build artefact XCT trial Cut-up & micro XCT Validation Design 2 nd iteration Update standard document Build 2 nd iteration artefact Trial with other NDT methods Validation Update standard document Incorporate feedback into standards document Complete document Submit final draft

11 ISO TC 261/ASTM F42 JG59 NP General Principles Non-destructive Testing of Additive Manufactured Products ISO/ASTM joint group activity led by MTC through British Standards Institute (BSI). Ben Dutton, Principal Research Engineer at MTC is the convener. This standard is to provide a best practice guide presenting NDT methods potential to detect defects which are not covered by current standards. Post-built NDT In-process NDT Draft has been generated. MTC Aim for final submission Dec 2018.

12 Scope of the Standard Categorises AM defects Reviews relevant current standards Enables suitable current standard NDT method(s) to be used Create and test star artefact in different materials Outline an à la carte approach to AM certification

13 Classification of AM Defects For NDT what is important is the defect morphology and the following are unique to AM: Causes Mode offailure Defects 1. Layer 2. Cross-layer 3. Unconsolidated powder 4. Trapped powder 5. Inclusion 6. Layer shift

14 Typical Powder Bed Fusion (PBF) Defects Cross layer Porosity/void Layer Trapped Powder Unconsolidated powder Cross layer, layer, trapped powder and unconsolidated powders are not present in existing welding, casting and subtractive machining standards. Therefore, it is not possible to simply copy across existing standards and techniques for these type of defects. Other defects not shown: lack of geometrical accuracy/steps in the part, reduced mechanical properties, inclusions, cracks and rough surface.

15 Typical Direct Energy Deposition (DED) Defects Porosity Hole or void Poor surface finish. Incomplete fusion Undercuts at the toe of the welds between adjoining weld beads Cracking Other defects: lack of geometrical accuracy/steps in the part, non-uniform weld bead and fusion characteristics and inclusions.

16 Review of Existing NDT Standards Additive manufacturing defects identified in AMAZE were reviewed and a library of defects was generated. The defects ware based on two AM processes: Direct Energy Deposition (DED) Powder Bed Fusion (PBF) Defects that are relevant for NDT were considered for review against existing standards in welding and casting. The results are summarised in the table. Green defects that can be covered by current standards Red defects that are not covered by current standards, and therefore require new standard. These defects are unique to additive manufacturing.

17 Artefact Design Star Artefact Standard artefact designed to test the detection capability of NDT methods - currently on second design iteration. Seeded defects were created as features in the CAD model. Defect geometries were repeated with different dimensions and in various orientations. Star geometries adapted to material density, based on 450 kv x-ray CT penetration. Three star designs for each material: Reference No defects; Design 1 Defect regions in thick wall sections; Design 2 Defect regions in thin wall sections. Standard artefact with known defects makes technology assessment and comparison more straightforward.

18 Artefact Design (S1) Star Artefact Version 1 Defect regions in thick wall sections; Design shown for Hastelloy-X; Hastelloy-X very dense, so is smaller in form relative to less dense materials; All samples printed are serialised for tracking through trials;

19 Artefact Design (S2) Star Artefact Version 2 Defect regions in thin wall sections; Design 2 hypothesised to be possibly easier to inspect for some technologies due to less wall penetration required; Conversely, defects in thin wall sections may be subject to more build error. Design shown for Hastelloy-X; Hastelloy-X very dense, so is smaller in form relative to less dense materials; All samples printed are serialised for tracking through trials;

20 Artefact Design À la carte Artefact Task-specific artefacts can be designed that are customised for the application of interest. These artefacts follow the same CAD-seeded defect approach. Example of such an à la carte artefact is the generic air foil artefact produced by GE Power. This is an example which will be used to indicate the process to follow for the specific AM part to be built/inspected. It will be recommended to place/seed the AM defects at the particular structurally critical locations and required sizes to be detected.

21 Artefact Materials Material Reference Version 1 Version 2 Cube Total Hastelloy X stars + 2 cubes Titanium more being manufactured Maraging steel stars + 2 cubes Other materials for contributing to the standard outside of this project include: Inconel 625; Cobalt-Chrome; Stainless Steel 17-4; Aluminium; and Titanium 64. Table showing the materials used specifically for the MTC NoSFAM project.

22 NDT Trials Trials of various NDT technologies with the artefacts are on-going. XCT Resonance Testing (PCRT and Non-linear) Ultrasonic Testing Single probe immersion Phased array/full matrix capture Trials carried out in collaboration with: end users; universities; instrument vendors; and national measurement institutes (NMIs). Thermography Non-linear Acoustic Neutron Tomography Radiography /Synchrotron

23 Standard Artefact Activity Post-build NDT methods In-process monitoring recommendation Artefact build PBF Association Neutron/Synchrotron Metrology Digital/live X-ray X-ray CT Flash Thermography Resonant/nonlinear testing Ultrasound SLM EBM ISO X X X BSI/ISO X ISO/ConceptLaser X X? ISO X X ISO X ISO/ANSI ASTM ASTM ASTM US Navy UL TWI X NPL STFC UoN X UoBirm? Theta Tec. X UoS? Encodema3D X GE X X RENISHAW BAE Systems X X GE Power X X IIL/BAM X X ESRF X NSI X NASA X X? ConceptLaser/GE Parker NPL RR Project AMAZE X X

24 Hastelloy-X Star Artefacts (S1, S2 and no defects) Manufacture Star artefacts presented here manufactured in Hastelloy-X. Laser powder bed fusion with 100 µm layer height. Hastelloy-X geometry based on nearest density material Nickel from XCT standard (10% transmission). Powder removal achieved using ultrasonic bath. Photographs of the Hastelloy-X samples.

25 Hastelloy-X Star Artefacts (S1) XCT Inspection Artefacts have been inspected using the Nikon XTH 450 system, and Volume Graphics VGStudioMAX. Defect detection of defects greater that 100 µm. Promising ability to resolve trapped powder defects. Photograph of the Nikon XTH 450 (Nikon, 2018). Quad-view from VGStudioMAX of the XCT scan (layer defects).

26 XCT of Hastelloy-X Artefacts (S2) Schematic (left) showing the location of (crosslayer) defects and presence in XCT scan (right).

27 XCT of Hastelloy-X Artefacts (S2) Schematic (left) showing the location of (unconsolidated powder) defects and presence in XCT scan (right).

28 XCT of Hastelloy-X Artefact (S1) Defects Built/Detected Version Region Description Defect Detected- Y/N S1 1 Cylinders, length 2 mm, equal diameter Ø = 0.30 mm, vary angle orientation 2 Vertical cylinders, length 5 mm, vary Ø 3 Spheres with trapped powder. Vary Ø. 4 Horizontal cylinders, from outside, length 3 mm, vary Ø 5 Horizontal cylinders, length 2 mm, vary Ø 45 deg 1st Y 45 deg 2nd Y 45 deg 3rd Y 45 deg 4th Y horizontal (radial) Y horizontal (tangential) N vertical Y 0.7 Y 0.6 Y 0.5 Y 0.4 Y 0.3 Y 0.2 N 0.1 N 0.7 Y 0.6 Y 0.5 Y 0.4 Y 0.3 Y 0.2 N 0.1 N 0.7 Y 0.6 Y 0.5 Y 0.4 Y 0.3 Y 0.2 N 0.1 N 0.7 Y 0.6 Y 0.5 Y 0.4 Y 0.3 Y 0.2 N 0.1 N

29 Other NDT Standard Developments ASTM E07 WK47031 Standard Guide for NDT of AM Metal Parts Used in Aerospace Applications I helped initiate and I am currently participating as an NDT expert SAE AMS7003 Laser Powder Bed Fusion Process I am participating in the NDT section

30 Summary Rapid growth in application of AM processes is driving demand for inspection standards. A new NDT standard for AM based upon artefacts with seeded defects has been proposed, and is being drafted. An application-specific à la carte artefact format is proposed to be followed for your specific part design. Trials have been carried out to: Validate the seeded artefact defect design; Assess a range of NDT techniques. The standard will be submitted for review at the end of 2018 Realising the full potential of AM will depend upon the definition and acceptance of comprehensive industrial standards.

31 Thank you Ben Dutton