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Design & Manufacturing

Demands in

Laser Automotive Prototyping

Gordon McIntosh President, SWS-Trimac

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• SWS-Trimac, Inc. is an Engineering company that

specializes in Electron Beam & Laser Welding,

CNC Machining, and non-destructive testing. From

small-lot prototype development to production.

• SWS-Trimac, Inc. has been serving the needs of the

Automotive, Defense, Aerospace, Biomedical, and

Machine Tool Industries for nearly 50 years.

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Laser Applications

Previous Experience in Automotive Applications

Transmission Components Battery Components

Driveline Fuel Cell Technology

Reclining Seats Electric Motors / Servos

Fuel Rails Air Bags

Detent Cables Steering Columns

Spark Plugs Fuel Injectors

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Laser Welding Environments

• Welding Environments

– Safe

– Versatile

– Efficient

– Repeatable

– Work Stations May Vary Greatly

– Manual, CNC Tables/Gantry, Robots, Etc.

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Laser Welding Recommended Practices

• Successful Welding Requirements

– Weldable Materials

– Avoid High Carbon, Carbonization, Free-Machining Materials

– Sound Weld Joint Design

– Adequate Cleaning Technique

– Proper Weld Joint Fit-Up / Avoid Excessive Gaps & Chamfers

– Sound Laser Setup & Tooling

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Material Selection

• Weldable Materials

– Avoid High Carbon Materials whenever possible

• Crack Sensitive

– Consider pairing with material with a lower carbon content.

– Use of ductile filler materials.

– Weld techniques may be tailored to offer post-weld tempering

pass to localize anneal

• Reduce hardness in some applications.

– Carburization Carefully

• In fusion zone will lead to cracking & porosity every time.

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Material Selection

• Weldable Materials

– Carburization (No Carb Zones)

» Geometry Example

• Avoid Free-Machining Materials

– Phosphorus (P), Sulfur (S), Lead (Pb), Zinc (Zn),

Tin (Sn) act as contaminates in fusion zone; will

cause spit-ups, porosity & cracking

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Weld Joint Selection

• Sound Weld Joint Design

– Common Weld Joint Designs

– Butt Joints (Axial & Radial)

– Piloted

– Non-Piloted

– Linear

– Lap Joints (Seam Welds)

– Fillet Joints

– Integral Filler Steps

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Weld Joint Selection

• Butt Joints

– Most Common

– Piloted joints are preferred as they minimize post-

weld distortion and need for elaborate weld

tooling.

– Applications with crack sensitive materials or high

demand for post weld tolerance should consider an

interference fit.

– Tight fitting joints (Compression) reduce the post-

weld tensile stress due to the inherent shrink across

the weld joint.

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Weld Joint Selection

• Butt Joints

– Piloted Examples

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Weld Joint Selection

• Butt Joints

– Non-piloted joints can be challenging to weld as

weld tooling becomes more of a factor when

maintaining post weld true position & distortion.

Base material(s) that are crack sensitive create

other obstacles when choosing a non-piloted joint.

» Example

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Weld Joint Selection

• Butt Joints

– Linear

• Linear butt joints should be designed to freely

shrink; special consideration should be made for

multiple opposing linear welds.

– Linear Butt Joint, with Backer

» Example

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Weld Joint Selection

• Lap Joints (Seams Welds)

– Weld strength is equal to weld area at interface.

– Weld surfaces should make intimate contact to

assure best results.

– Interruption in contact will promote additional part

distortion.

» Example

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Weld Joint Selection

• Fillet Joints

– Commonly done although Crack sensitive

materials can be especially tricky.

– Many Laser applications are done without the use

of filler material.

– In some cases, filler material may be added via

wire feed, filler shim, or filler wire added manually

in separate operation.

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Weld Joint Selection

• Fillet Joints continued

• The addition of a small, integrated filler step to

increase weld puddle volume is always welcomed.

• Step may be added either component.

» Example

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Laser Weld Preparation

Adequate Cleaning Technique

– All weld joint surfaces should be thoroughly

cleaned prior to weld.

– What needs to be cleaned?

– Cleaning Techniques

– Quality Control

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Laser Weld Faying Surfaces

Proper Weld Joint Fit-Up

– Assembly methods are dependent upon joint

design, regardless of weld joint all welds should be

free of excessive gaps and chamfers.

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Laser Welding Summary

Sound Laser Setup & Tooling

– Welding Technique & Tooling will be driven by part

specific applications.

– Material Type

– Joint Design

– Cross Section Thickness

– Part Geometry

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Laser Welding Open Set-up

• Rofin Sinar Laser CO2

– Laser CO2 Welding

in Open Environment

– Rotary application in

stationary fixturing

“Z” table.

– Wave length of CO2

beam allows for more

versatile, barrier-free

welding.

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Laser Welding Dual Station Production Cell

• Trumpf TruDisk

– Dual station cabinet

– Weld containment, fully interlocked

– Beam switching between two stations

– Manual X-Y and fully adjustable Z with fully adjustable

weld head

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Laser Welding Prototype Cell #1

• Trumpf TruDisk

– 3D PFO Weld Head Suspended over CNC Table

– Weld head may be used for Laser Scanning or conventional

static beam spot welding.

– CNC table allows for part movement in X-Y with rotary

capability.

– Very versatile for welding of small to medium sized parts.

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Prototype Laser Weld Cell #2

• Trumpf TruDisk

– Stationary D70 Weld Head

– Mounted over 4’ x 6’ envelope

– 8” Z-axis Travel

– Aerotech CNC Controlled X-Y 24” x 24” Travel

– Fully adjustable Manual Collet Fixture with integrated

CNC controlled U axis

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Thank You!

– Question & Answer

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