LaserPipe In-bore laser welding feasibility study Feasibility study part funded by Innovate UK Thursday, 19 th November 2015
Agenda LaserPipe demonstration day Partner company overviews LaserPipe project overview Laser welding development Alignment mechanism development Integration testing and trials Live demonstration Way forward for LaserPipe Questions Lunch
LaserPipe partner overview OC ROBOTICS
OC Robotics reaching the unreachable OC Robotics is a leading provider of robotic systems for use in confined or hazardous environments A wealth of experience designing and delivering robotic systems to key industries, such as; nuclear, aerospace, construction, defence and oil & gas
OC Robotics reaching the unreachable Borescopes Small, flexible inspection tools for accessing confined areas with limited controllability. Snake-arm robots Snake-arm robots fit in between borescopes and industrial robots. They are highly flexible, multi DOF robots that are able to deliver a payload into a small confined space. Industrial robots A stiff, stable platform for repeatedly moving large objects.
OC Robotics reaching the unreachable Insert system overview Cartoon of pack and arm or picture
OC Robotics reaching the unreachable https://youtu.be/_gu6twgynku
LaserPipe partner overview TWI
TWI Introduction to TWI Independent research and technology organisation, established in Cambridge, UK in 1946 A world centre of expertise in manufacturing, fabrication and wholelife integrity management technologies ~700 Industrial Members operating in over 4500 locations worldwide In 2014, ~ 80m of R&D and training in materials joining and related technologies was performed ~1,000 staff world-wide
TWI Materials processing at TWI Laser joining of metallic materials Laser welding, hybrid laser-arc welding, laser brazing Laser cutting of metallic materials Laser surfacing of metallic materials Micro-machining Surfi-Sculpt Laser-based cladding processes Additive manufacturing Laser Metal Deposition (LMD) Selective Laser Melting (SLM) Laser processing of ceramic and polymeric materials Lasers for (nuclear) decommissioning
LaserPipe PROJECT OVERVIEW
Project overview Background Modern industrial operations often require complex and extensive pipelines, leading to maintenance issues: Confined spaces Limited external access to pipes Hazardous working conditions Worker dose (nuclear) External orbital cutting and welding not viable Limited operational windows Significant cost of extended plant shut down Example of pipelines found in a nuclear environment (courtesy of Sellafield Ltd)
Project overview Background Traditional orbital cutting and welding technology not suitable due to limited access and proximity to other plant. Typical orbital welding tool for pipeline (TIG)
Project overview LaserPipe feasibility study Problem: Identify a suitable welding technology to deploy within pipelines for in-bore welding Determine a method of access and alignment to reach the weld site Solution Laser welding - scope for miniaturisation, flexibility of fibre, speed of weld, proven technology across many industrial applications Snake-arm technology allowing repeatable access to confined spaces and accurate delivery of payloads, including alignment
Project overview Key objectives for feasibility study Use of available COTS snake-arm Use of available COTS optics Identify welding parameters Minimising total mass and footprint of payload: Alignment mechanism Laser welding optics Laser welding assembly Services (cameras, laser diodes, laser fibre, water cooling, air knives, shielding gas). Alignment Beam dump and external gas shielding
Project overview Major system components Laser generator Snake-arm robot Alignment mechanism Welding assembly
LaserPipe LASER WELDING DEVELOPMENT
Key development aims Laser welding development Using COTS optics produce an assembly capable of multipositional in-bore welding to determine feasibility. Positions: PE, PF, PG, PA
Key development aims Laser welding development Successful system must be capable of deployment using available snake-arm technology: Total mass including services and alignment mechanism <5kg Capable of >360 degree rotation Small enough to navigate in/around then weld standard pipe Inner Diameters (IDs) Produce a welding result at recognised standards: BS EN 13919-1 Welding - Electron and laser-beam welded joints - Guidance on quality level for imperfections - Part 1: Steel
Weighting Factor Does not require a focussing lens 4.1% Camera Visibility is in the plane of view 3.0% likely size of Laser head design 10.1% Pipe size (small and Large) 9.5% Variable focal length to compensate for positional inaccuracies (rings/spacers) 1.8% Likely Cost to project 8.3% Protection system (Air/Argon) 6.5% Design and build effort 7.7% Mirror Cleaning ability/ Maintenance 13.0% Ease of Mirror setup tolerance 13.0% Extra Feature 1 10.7% Extra Feature 2 0.6% Extra Feature 3 11.8% Scoring system Laser welding development Beam Bending Cube (BBC) Target Factors Use of Flat Mirror (FM) Use of Parabolic Mirror (PM) Benefit Rate (Target factor x Weighting factor) Use of Use of Beam Bending Flat Parabolic Cube Mirror Mirror (BBC) (FM) (PM) 1=Lens not needed 0=Lens needed 0 0 1 0.000 0.000 0.041 1=Can achieve in plane view 0=Out of plane view only 1 0 0 0.030 0.000 0.000 3= Small head 2=Medium head 1= Big head 1 2 2 0.101 0.201 0.201 1=Big and small pipes 0=Big pipes only 0 1 1 0.000 0.095 0.095 1=Yes 0=No 0 1 0 0.000 0.018 0.000 3= Cheapest cost 2=Medium cost 1= Most Expensive 2 3 1 0.166 0.249 0.083 1=Air knife 0= Ar Knife 1 0 0 0.065 0.000 0.000 3= Least intensive 2=Medium Intensity 1= Most intensive 3= Least intensive 2=Medium Intensity 1= Most intensive 3= Least intensive 2=Medium Intensity 1= Most intensive 3 2 1 0.231 0.154 0.077 3 2 1 0.391 0.260 0.130 3 2 1 0.391 0.260 0.130 1=Yes 0=No 0 1 1 0.000 0.107 0.107 1=Yes 0=No 1 0 0 0.006 0.000 0.000 1=Freely rotate 0=Not Freely rotate 0 1 1 0.000 0.118 0.118 Summary 100% 15 15 10 1.379 1.462 0.982 67.5% 71.6% 48.1% % of Best Case
Max. mirror T after 35s, 'C Laser welding development Copper mirror testing W= 75-80 g (f60-f500) (We have f200 & f400) W= 600g (For f100) 41.83mm 50.0mm 81.83mm 100.0 Water cooled mirror temperatures 118.0mm (236mm ID Pipe) 80.0 60.0 40.0 20.0 0.0 41.83mm stand-off 50mm stand-off 81.83mm stand-off 0 1000 2000 3000 4000 5000 158.17mm (316.34mm ID Pipe) 150.0mm (300mm ID Pipe) Power requested from laser, W
Laser welding development Welding assembly design and development Primary 304L stainless steel pipe for trials OD 273.05 ID 264.67mm, Wall thickness 4.19mm
Laser welding development Beam dump and outer gas shielding collar Collar required for: Exterior weld shielding to reduce oxidisation during weld Beam dump to safely confine laser The gas shielding collar features: Nitrogen inlet/outlet valves 2 hinged regions for pipe placement Machined channels for silicon O-rings and copper lining
Bead on Plate (BoP) trials Laser welding development 3mm 3Kw 5mm 3Kw 5mm 5Kw Speed (m/min) PA PG PF PE Speed (m/min) PA PG PF PE Speed (m/min) PA PG PF PE 0.50 0.50 3, -5 0.50 0.75 0.75 3, -5 0.75 1.0 7, -3 3, -3 3, -3 7, -3 1.0 3, -5 3, -5 3, -5 x 1.0 3, -5 3, -5 3, -5 2.0 7, -3 2.0 2, 0 2, 0 2, 0 x 2.0 3, -5 3, -5 3, -5 3, -5 2.5 7, -3 2.5 x x x x 2.5 3.0 7, -3 7, -3 7, -3 7, -3 3.0 x x x x 3.0 3, -5 3, -5 3, -5 3, -5 3.5 3, -3 3.5 x x x x 3.5? 4.0 3, -3 4.0 x x x x 4.0 3, -5 3, -5 3, -5 x 5.0 3, -3 3, -3 3, -3 3, -3 5.0 x x x x 5.0??? x 5.5 x x x x 5.5 x x x x 5.5??? x 6.0 x x x x 6.0 x x x x 6.0??? x 7.0 7.0 7.0??? x Radiographic analysis (to determine the extent of weld porosity and spatter) show minimal weld defects in visually desirable welds. The most favourable weld parameters to take forward for the demonstration provide us with a wide weld width ~4mm.
Initial in-bore pipe welding trials Laser welding development
Initial In-bore pipe welding trials Laser welding development
Laser welding development Welding parameters identified by trials Laser power = 4 kw Weld traverse speed = 1 m/min Beam focus tolerance = +/- 4mm Tolerance to joint line = 0.2mm Beam biasing to either parent material = not applicable
LaserPipe ALIGNMENT MECHANISM DEVELOPMENT
Key development aims Alignment mechanism development Select an available COTS snake-arm suitable for deployment Provide a 6 DoF alignment system with resolution of movement to deliver TWI weld parameters
Alignment mechanism development COTS snake-arm delivery mechanism Series II X125 arm (2.5m inc. tool) 10 joints 22 DoF 5kg payload Can be skinned to protect against spatter
Alignment mechanism Alignment mechanism development Achieve welding parameters Keep mass low Remain agile for deployment in/around pipework End of snake arm Offset of laser orbit (radial movement) Rotation of laser head Axial seam tracking Tool
Alignment mechanism Alignment mechanism development Key design features: Hardware and software based solution Embedded collimator to reduce overall length Rotating mirror static collimator and focussing lens High resolution control of rotation (roll) Clearance for fibre (or collimator) through hinge core Laser collimator Fibre coming through link body (adjacent link or further down arm)
Alignment mechanism development Alignment mechanism and control Cartesian control of snake-arm to achieve: Translation (forward/back, up/down, left/right) Rotation (yaw, pitch, roll)
Alignment mechanism development Design of integrated system assembly with counter weight OCR trials proved snake-arm system stability suitable for rotation of welding assembly without counterweight Counter weight removed from design
Alignment process State-of-the-art 6-DoF Cartesian tool motion - Approximately align head by nose following into pipe - Translate guide laser focal point onto pipe surface at weld line - Rotate tool 120 degrees
LaserPipe INTEGRATION TESTING AND TRIALS
Integration testing and trials Initial integration at OC Robotics using dummy collimator and laser source Testing completed using actual mirror and welding assembly
Integration at TWI Collimator Focussing lens Fibre Services: Water lines Gas lines Shielding gas Successful integration Integration testing and trials
Integration testing and trials Trial achieving full penetration and good quality weld, although further analysis needed. https://youtu.be/jpboe1wh_6w
LaserPipe LIVE DEMONSTRATION
LaserPipe WAY FORWARD
LaserPipe way forward Finish current feasibility study Complete trials Analyse results Generate report Disseminate findings Project funding ends 2015
LaserPipe way forward Options for future work Improved gas shielding inside pipe panpipes/skirt Deployment system Application of technology for cutting/decommissioning Alignment camera shutter/air knife Further refinement of the alignment process Pipe features for pipe alignment and beam dump Remoted deployment of replacement/new pipe section Miniaturisation of optics / custom optics Sealed units without need for cover slides/air knives Air cooled optics
LaserPipe QUESTIONS AND ANSWERS
LaserPipe partner details OC Robotics Greg Udall Project manager 0117 3144 4700 gregudall@ocrobotics.com TWI Tony Pramanik Project leader 01223 899 255 tony.pramanik@twi.co.uk