laserpipe in-bore laser welding feasibility study · laserpipe in-bore laser welding feasibility...

©2015 OC Robotics®COMMERCIAL IN CONFIDENCE

Thursday, 19th November 2015

LaserPipeIn-bore laser welding feasibility study

Feasibility study part funded by Innovate UK

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LaserPipe demonstration day

• Agenda– Partner company overviews

– LaserPipe project overview

– Laser welding development

– Alignment mechanism development

– Integration testing and trials

– Live demonstration

– Way forward for LaserPipe

– Questions

– Lunch




OC ROBOTICS

LaserPipe partner overview




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




Borescopes Industrial robotsSnake-arm robots

Small, flexible inspection tools for

accessing confined areas with

limited controllability.

A stiff, stable platform for

repeatedly moving large objects.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.





• Insert system overview– Cartoon of pack and arm or picture






https://youtu.be/_gU6TWGynkU



https://youtu.be/_gU6TWGynkU


TWI

LaserPipe partner overview




TWI

• Introduction to TWI

• Independent research and technology organisation, established in Cambridge, UK in 1946

• A world centre of expertise in manufacturing, fabrication and whole-life 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




PROJECT OVERVIEW

LaserPipe




Project overview

• Background– Modern industrial operations often require complex and

extensive pipelines, leading to maintenance issues:

Example of pipelines found in a nuclear

environment (courtesy of Sellafield Ltd)

• 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




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




LASER WELDING DEVELOPMENT

LaserPipe




Laser welding development

• Key development aims– Using COTS optics produce an assembly capable of multi-

positional in-bore welding to determine feasibility.

• Positions:

– PE, PF, PG, PA





• Key development aims– 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





Target FactorsBenefit Rate

(Target factor x Weighting factor)

Weighting Factor

Scoring system

Beam Bending

Cube (BBC)

Use of Flat Mirror (FM)

Use of Parabolic

Mirror (PM)

Beam Bending Cube (BBC)

Use of Flat

Mirror (FM)

Use of Parabolic

Mirror (PM)

Does not require a focussing lens 4.1% 1=Lens not needed0=Lens needed 0 0 1 0.000 0.000 0.041

Camera Visibility is in the plane of view

3.0% 1=Can achieve in plane view0=Out of plane view only 1 0 0 0.030 0.000 0.000

likely size of Laser head design 10.1%3= Small head

2=Medium head1= Big head

1 2 2 0.101 0.201 0.201

Pipe size (small and Large) 9.5% 1=Big and small pipes0=Big pipes only 0 1 1 0.000 0.095 0.095

Variable focal length to compensate for positional inaccuracies

(rings/spacers)1.8% 1=Yes

0=No 0 1 0 0.000 0.018 0.000

Likely Cost to project 8.3%3= Cheapest cost2=Medium cost

1= Most Expensive2 3 1 0.166 0.249 0.083

Protection system (Air/Argon) 6.5% 1=Air knife0= Ar Knife 1 0 0 0.065 0.000 0.000

Design and build effort 7.7%3= Least intensive

2=Medium Intensity1= Most intensive

3 2 1 0.231 0.154 0.077

Mirror Cleaning ability/ Maintenance 13.0%3= Least intensive


3 2 1 0.391 0.260 0.130

Ease of Mirror setup tolerance 13.0%3= Least intensive


3 2 1 0.391 0.260 0.130

Extra Feature 1 10.7% 1=Yes0=No 0 1 1 0.000 0.107 0.107

Extra Feature 2 0.6% 1=Yes0=No 1 0 0 0.006 0.000 0.000

Extra Feature 311.8% 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 0.98267.5% 71.6% 48.1%

% of Best Case





• Copper mirror testingW= 75-80 g (f60-f500) (We have f200 & f400)

W= 600g (For f100)

41.83mm

158.17mm(316.34mm ID Pipe)

50.0mm

150.0mm(300mm ID Pipe)

81.83mm

118.0mm(236mm ID Pipe)

0.0

20.0

40.0

60.0

80.0

100.0

0 1000 2000 3000 4000 5000

Ma

x. m

irro

r T

aft

er

35

s, 'C

Power requested from laser, W

Water cooled mirror temperatures

41.83mm stand-off50mm stand-off81.83mm stand-off





• Welding assembly design and development

Primary 304L stainless steel pipe for trials

• OD 273.05 ID 264.67mm,

• Wall thickness 4.19mm





• 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

• 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.

3mm 3Kw 5mm 3Kw 5mm 5Kw

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





• Initial in-bore pipe welding trials





• Initial In-bore pipe welding trials





• 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




ALIGNMENT MECHANISM DEVELOPMENT

LaserPipe




Alignment mechanism development

• Key development aims– Select an available COTS snake-arm suitable for deployment

– Provide a 6 DoF alignment system with resolution of movement to deliver TWI weld parameters





• 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– Achieve welding parameters

– Keep mass low

– Remain agile for deployment in/around pipework

Offset of laser orbit

(radial movement)

Rotation of laser

head

Axial seam

tracking

End of snake arm

Tool





• Alignment mechanism– 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)

Laser collimator

Fibre coming through link body

(adjacent link or further down

arm)

Clearance for fibre (or

collimator) through hinge

core





• Alignment mechanism and control– Cartesian control of snake-arm to achieve:

• Translation (forward/back, up/down, left/right)

• Rotation (yaw, pitch, roll)





• 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




• State-of-the-art 6-DoF Cartesian tool motion

Alignment process

- Approximately align head by nose following into pipe

- Rotate tool 120 degrees

- Translate guide laser focal point onto pipe surface at weld line




INTEGRATION TESTING AND TRIALS

LaserPipe




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





• Trial achieving full penetration and good quality weld, although further analysis needed.

https://youtu.be/jpbOE1wH_6w



https://youtu.be/jpbOE1wH_6w


LIVE DEMONSTRATION

LaserPipe




WAY FORWARD

LaserPipe




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




QUESTIONS AND ANSWERS

LaserPipe




OC Robotics

• Greg Udall

– Project manager

• 0117 3144 4700

• [email protected]

TWI

• Tony Pramanik

– Project leader

• 01223 899 255

• [email protected]

LaserPipe partner details



laserpipe in-bore laser welding feasibility study · laserpipe in-bore laser welding feasibility...

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