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Fundamentals of pulsed Nd:YAG and fiber laser...

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Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals Elements of a laser welding system The route to a successful weld
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Page 1: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

Fundamentals of pulsed Nd:YAG and fiber laser welding

Laser fundamentals

Elements of a laser welding system

The route to a successful weld

Page 2: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Laser Fundamentals

Page 3: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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What is a laser..

• Elements of any laser

– Laser medium

– Pump energy for medium

– A resonator that controls the

generation and amplification of the

laser

Light

Amplification by

Stimulated

Emission of

Radiation

Page 4: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Laser Generation

1. Spontaneous emission – the seed

2. Stimulated emission – the amplification

3. Controlled amplification in

resonator

Page 5: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Processing fundamentals

• The laser must be focused for materials processing

Page 6: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Elements of a laser welding

system

Page 7: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Laser Welding System

1. Laser 2. Beam delivery

3. Focusing head

Elements of a laser welding system

4. Process

5. Tooling &

Motion

Fiber /

mirrors

Lens

Weld

Laser

Beam delivery

Focusing head

Process

Tooling & Motion

Page 8: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Pulsed Nd:YAG laser

• Micro welder (<0.02” penetration)

Welding Lasers

Air bag detonator Seam welding

implantatable

devices

Aluminum battery Medical tool

connect

Nd:YAG

Page 9: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Very flexible

• Highly controllable

• Lowest heat input of any welding laser

• Robust industrially proven

– Very reliable

– Many parts field replaceable

• Energy / time share

– Optimize laser usage, multiple welds per part

• Fiber delivery

– Locate laser where its convenient

– Standard fiber lengths 5,10 & 20m (longer available)

Features of pulsed Nd:YAG welders

Page 10: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Welding Lasers

Pulley wheel Copper battery tabs

Steering column assembly

Crank case

• Continuous Wave (CW) lasers

– Fiber laser

• Penetration welder (>0.04”)

Page 11: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Excellent penetration and speed performance

• Efficient welding mechanism

• Fiber delivery

– Locate laser where its convenient

– Standard fiber lengths 5,10 & 20m (longer available)

• Wall plug efficiency up to 30%

• Energy / time share

– Optimize laser usage, multiple welds per part

Features of Fiber laser welders

Page 12: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Comparison of pulsed and CW lasers

• Pulsed Nd:YAG lasers

– Micro spot welder

– Fine control of weld energy

– Pulse durations typically 0.1 – 10ms

– Peak power up to 250 times average

• 25W laser provides 6kW peak power

• Average power = heat input, welding speed

– Large welding spot size (400-600 microns)

• Continuous wave

– Penetration welder

– High speed seam applications

– Power range 1 – 5 kW

– Peak power is the same as

average power

Power

Pulsed Nd:YAG output Continuous wave or gated output

Power

Peak power

Average

power

Average

power

10% duty cycle

Page 13: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Laser Beam Delivery

Delivering the laser to the workpiece

Page 14: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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The laser – where it starts

Page 15: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Part

Fiber Optic

Focusing

Head CCTV

Camera

Fiber Optic end

Fiber Optic Delivery + Focus head

Page 16: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Part

Part

Collimating Lens

Focusing Lens

Protective Cover Slide

CCTV

Camera

Working distance

Focus head

Fiber optic

From laser

Page 17: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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The Route to a

Successful Weld

Design for Laser Welding

Page 18: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Materials, Joint geometry, Penetration, Cycle Time

Defining the requirements of the weld

Part tolerances, Fit-up, Laser parameters

The Required Weld

Page 19: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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The Required Weld

• What is the purpose of the weld

– Mechanical / electrical / sealing

• Inspection techniques

– Weld cross section

– Pull/peel testing

– Pressure testing

– Resistance

– Hermeticity

• Optimizing penetration requirements

– Reduce laser size

– Increase speed

Page 20: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Material selection for pulsed Nd:YAG Welding

Material Comments

Aluminum

Welding is limited to certain grades such as 6061 to 4047 or 4032, 1050, 1100, 3003 and 5005. High

energy levels required to overcome surface reflectivity. Other aluminum alloys should be tested

thoroughly for joint design and crack sensitivity.

Beryllium Copper Good welds. Alloys containing less copper are best due to reduced reflectivity. A safety hazard

exists from the toxic beryllium oxide fumes

Carbon Steel Good welds, carbon content should be less than 0.12%.

Copper Generally limited to spot welds. High energy levels required to overcome surface reflectivity.

Hastalloy-X Good welds

Kovar Good welds

Molybdenum Good welds, slight brittleness.

Nickel Good welds

Phosphor Bronze Good welds

Stainless steel

304 & 304L produce excellent welds

316 & 316L are ok provided Cr/Ni ratio is greater than 1.7

Other 300 series require testing, though 303 should be avoided

400 series require testing for crack sensitivity.

Titanium Good welds, gas shielding is key

Page 21: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Material Relative weld energy

Low Alloy Steel 1

Titanium 1.5

Stainless Steel 1.5

Aluminum 3.5

Copper 5+

Material selection – size of laser & process

speed

Page 22: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Material selection

• Stick to your recommended vendors!

Page 23: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• OK

– Nickel coated

– Gold coated (to around 1 micron)

– Electrolytic process

– Zinc (weld spatter)

– Tin (weld spatter)

• Bad

– Thick plating

– Electroless plating

process

Material generally welds better without plating

Material plating

Page 24: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Fillet Butt

Lap

• Select for efficiency – Tolerance to fit-up, speed, strength

• For best results - NO GAP between parts!

Joint Geometry & Fitup

Page 25: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Gap allowed around 10% of beam diameter

Butt weld

Page 26: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Gap allowed around 25% of beam diameter

Lap weld

Page 27: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Gap allowed around 15% of beam diameter

Fillet weld

Page 28: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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The Process

Fiber and focus head

selection

Page 29: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Selecting Fiber and Focus head for Application

Part

Fiber Optic

Focusing

Head

CCTV

Camera

Fiber Optic end

Spot size = core diameter of delivery fiber x focus lens

collimator lens

Spot size

Page 30: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Size of Parts

• What makes sense, size to component & joint

Laser

Laser

Spot size too large

Page 31: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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75mm Focal length

Small spot size, small

vertical tolerance

Large spot, large

vertical tolerance

125 mm Focal length

Depth of focus

Page 32: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Working

distance

Working distance

• Accommodation of tooling / peripheral equipment

Page 33: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Fit up tolerances

• Gap between parts & positional variance

Good fit-up & position Poor fit-up

0.02” spot size 0.04” spot size 0.04” spot size

Laser Laser Laser

Poor position

repeatability

Page 34: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Weld stability

• Increasing spot size increases weld stability

• Aluminum key material

– Disturbances in weld pool are magnified by low viscosity

– Large spot size = large melt pool = more damping effect

• Throwing a stone into a bigger pond!

Page 35: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Summarizing the optics selection

• Define required spot size

– Select focus lens for working distance

– Select fiber core diameter for power (pulsed Nd:YAG laser only)

– Select collimator to fit

Page 36: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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The Process

Laser parameters

Page 37: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Heating with a laser – The big picture

Page 38: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Welding modes

• Low energy density heat source relies on conduction from the surface

• Shallow welds

• Large heat input

• High energy density heat source such as laser welding produce an internal heating effect by the creation of a vapor filled element know as a keyhole welding to increase penetration

• Narrow deep welds

• Small heat input

CONDUCTION KEYHOLE

Page 39: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Welding with a laser - Welding modes

Conduction Partial Keyhole Full Keyhole

Increasing laser

power density

Page 40: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Peak Power (kW) – Main parameter that determines weld penetration.

• Pulse Width (ms) – Effects width and penetration

– Pulse Energy (J) – Peak power x pulse width.

P

Time

Pulse

width

Peak power

Pulse

energy

Pulsed Nd:YAG Laser Parameters

Page 41: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Controls penetration depth

– Too high causes porosity & drilling

Increasing peak power

Effect of Peak Power

1kW 1.5kW 2kW

Page 42: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Increases width and depth

Effect of Pulse width

Page 43: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Effect of Peak power & pulse width

Material: Titanium (0.02” spot size)

0.02”

Page 44: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Pulse Repetition rate (Hz) – number of pulses that the laser fires per second

• Pulse overlap (% of weld diameter) – how much subsequent pulses overlap

– Average power (W) - peak power x pulse width x repetition rate.

P

Time

Pulse

width

Peak power

Average power

Pulse repetition rate or Frequency = 1/ pulse period

Pulse

period

Pulse

energy

Seam Welding Laser Parameters

Page 45: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Overlapping spots

• Overlap % - function of speed, pulse repetition rate and weld spot diameter

• Rule of thumb settings – 60-70% spot overlap for strength

– 80-90% spot overlap for hermaticity

– Small laser can seam weld, just slower

50% overlap

85% overlap

Effective

penetration

Page 46: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Sizing the laser

• Lasers are described in average power

– A 400W laser can provide 400W average power

– Example: Weld requires 4kW at 5ms = (4kW x 5ms) = 20J

• How fast can we pulse with a 400W laser?

• 400W / 20 J = 20 Hz (20 times per second)

• Welding speed = (1 - overlap) x spot size x frequency

Page 47: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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• Average Power (kW) – Main parameter that determines weld penetration.

• Spot size selection important

P

Time

Average power

Fiber Laser Parameters

Page 48: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Power vs Speed for Fiber Laser

3kW

5kW

40ipm 60ipm 80ipm 100ipm

Page 49: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Single Mode and Multi Mode fiber lasers;

the importance of spot size

• 500W single mode laser

• 1.5mm thick steel at 300ipm with

30 micron spot size

• 1kW multi mode laser

• 1.5mm thick steel at 40ipm with

200 micron spot size

Page 50: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Role of Shielding gas for pulsed Nd:YAG laser

• Prevents oxidation

• Produces aesthetic shiny weld

• Required for titanium, inconels,

• Laminar flow

Part Travel

Off axis diffuser

Argon

cover

No

cover

Page 51: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Role of Shielding gas for fiber laser

• Prevents oxidation

• Welding plume suppression

• Active gas pressure

Part Travel

Off axis gas jet

Welding plume

Page 52: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Laser Process & Integration features

• Real time power feedback

• Energy/Time share – multiple outputs

• Excellent pulse to pulse stability

• Pulse Shaping (Fix and Flex Modes)

• Laser Power Ramping (seam welding)

Page 53: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Internal Laser Power Feedback at Work

Laser

HR PR

Lamp Power

Supply

lamp

Comparator

Power

Detector

Input

Coupling

Assembly

Power Monitor

VOUT = 1V/kW

DSP Reference

Waveform

Feedback

Waveform

Demanded pulse

Supplied pulse

• All Miyachi pulsed Nd:YAG and fiber lasers

• Same power delivered to workpiece every time, all the time

Page 54: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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10

Watts

10

Watts

100%

Mirror

0

Watts

100%

Mirror

The Laser - Time Share: Welds Sequentially

Page 55: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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10

Watts

10

Watts

100%

Mirror 100%

Mirror

0

Watts

The Laser - Time Share: Welds Sequentially

Page 56: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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50% Mirror 100%

Mirror 10

Watts

5

Watts

5

Watts

The Laser - Energy Share: Welds Simultaneously

Page 57: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Pulse Shaping

• Pulse Shaping

– FIX Mode (3 segments)

– FLEX Mode (20 segments)

• Applications; welding aluminum, crack alleviation

Page 58: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Laser Power Ramping

• Available in all LW50A – LW600A Lasers, FL fiber lasers.

• Example of Power Ramping:

Without Power Ramping A series with Power

Ramping

Page 59: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Tooling & Motion

Page 60: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Tooling (you can’t weld air)

• Tooling functions

– Clamp parts with minimal gap at the weld interface

– Consistent positioning under laser

– Flexibility

– Ease of use

– Heat sink

• Modeling

Page 61: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Part Alignment & seam tracking - Nominal Values

Includes Part Tolerances

+/-0.003”

+/-0.010”

Variance in:

• X direction is critical

• Y is travel direction

• Z is forgiven due to

large focusing tolerance

Page 62: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Motion

• How many axis are required to weld the part (s)

• How accurate does the positioning need to be

• How fast do the stages need to move

• Does the laser or the part move

Page 63: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Putting It All Together

Page 64: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Laser Settings:

•Peak Power / Pulse Energy

•Pulse Width

•Pulse Repetition Rate

Beam Delivery:

•Fiber Core Diameter

•Focus Head Collimating Lens

•Focus Head Focus Lens

Average Power ,Spot Size, Power / Energy Density,

Spot Overlap (Seam Welding)

Process Requirements - define the required weld

Materials, joint geometry, cycle time, part fit-up,

part tolerances

A FULLY UNDERSTOOD & CONTROLLED WELD!!!!!

Page 65: Fundamentals of pulsed Nd:YAG and fiber laser weldingemax-associates.com/downloads/LaserWeldingFundamentals.pdf · Fundamentals of pulsed Nd:YAG and fiber laser welding Laser fundamentals

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Welding in Production

• Bench mark weld

– Visual, penetration, sensitivity

• Standardize set-up procedures

• Power checks

• Troubleshooting

– Work from the material backwards


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