Laser Cutting of Composites and Ceramics - AILU · Laser Cutting of Composites and Ceramics Laser processing of polymer, metal and ceramic composites ... beam either by laser scribing

Copyright 2008, GSI Group Inc.AILU

December 3, 2008

Laser Cutting of Laser Cutting of

Composites and CeramicsComposites and Ceramics

Laser processing of polymer, metal and ceramic compositesLaser processing of polymer, metal and ceramic composites

Wednesday 3 December 2008Wednesday 3 December 2008

RollsRolls--Royce Factory of the Future within the Advanced Manufacturing Royce Factory of the Future within the Advanced Manufacturing

Research Centre (AMRC) with Boeing, Rotherham.Research Centre (AMRC) with Boeing, Rotherham.

Dr. Mo Naeem, GSI Group, Dr. Mo Naeem, GSI Group,

Laser Division, RugbyLaser Division, Rugby


December 3, 2008

Dr. Mohammed Naeem is Materials Process Development Group

Leader. He received an MTech degree in metallurgical quality control

from Brunel University in 1981 and a Ph.D. in glass fibre composites

from Loughborough University of Technology in 1985. He has over 20

years of experience in the support of industrial lasers with GSI Group,

Laser Division and has published over 160 papers on laser material

processing. He has previously served as Materials Processing

Manager and held several Important Engineering Development roles.

Brief BiographyBrief Biography


December 3, 2008

Lasers Precision Motion Laser Systems

GSI GroupGSI Group


December 3, 2008

OutlineOutline

• Introduction

• Laser processing

–Polymer based composites

–Metal based composites

–Ceramics

–Silicon wafers

• Summary


December 3, 2008

Composite materialsComposite materials

• A typical composite material is a system of materials composing of two or materials (mixed and bonded)

• Generally a composite material is composed of reinforcement (fibers, particles, flakes and/ or fillers) embedded in a matrix (polymers, metals or

ceramics).

Fiber Filler Flake Particulate Random


December 3, 2008

Benefits of compositesBenefits of composites• Light weight

• High strength to- weight ratio

• Surface properties

– Corrosion resistance

– Weather resistance

– Tailored surface finish

• Thermal properties

– Low thermal conductivity

– Low coefficient of thermal expansion

• Electrical property

– Non magnetic

– Rader transparency


December 3, 2008

ApplicationsApplications

Aerospace, Airbus (A380)

Automotive

The big DRIVE in automotive is from F1


December 3, 2008

Laser machining of compositesLaser machining of composites

• Machining of composite materials often poses challenge, particularly for

fine profiles and counters and for hybrid laminates consisting of two or more vastly dissimilar materials.

• Conventional approaches used for composites, such as water- jet machining are not always sufficient.

• Laser machining of composites may offer a solution to some of these problems, although the laser- material interactions are not well understood.

• Typical machining involves:

– Cutting

– Drilling

– Milling


December 3, 2008

A range of industrial lasers are currently available for laser material processing including polymer, metal and ceramic based composites.

100nm 400nm 10,600 CO2700nm1,064nm

Nd: YAG

532nm

Nd: YAG (x2)355nm

Nd: YAG (x3)266nm

Nd: YAG (x4)

157-351

Excimer lasers

1,030nm Disc laser

1,070-1,055nm Fiber lasers

Ultra- Violet

(UV)

VisibleInfra- Red

(IR)

Laser TypesLaser Types


December 3, 2008

Laser Choice?Laser Choice?

Currently CO2 and Nd: YAG dominate the laser material processing market

CO2 Laser (10.6um)

• Higher average power

• Lower capital and

operating cost

• Less expensive safety

precautions with CO2

wavelength

Nd: YAG Laser (1.06um)

• Fiber optic delivery

• Easy beam alignment, beam

switching and beam shearing

• Less floor space with laser and beam delivery

• Good with highly reflectively material (i.e. aluminum based alloys

etc.

• High peak powers with high energy per pulse


December 3, 2008

Mirror DeliveryMirror DeliveryMirror Delivery

CO2 laser, 10.6µm wavelength

Laser Workpiece


December 3, 2008

Fiber DeliveryFiber Delivery

Laser

Laser

Workpiece

Workpiece

Timeshare/Energy share Fiber System

Single Fiber System

Nd: YAG laser, 1.06µm wavelength


December 3, 2008

Two- Way Timeshare

Luminator FibersLuminator Fibers

Back reflection protection

patented technology


December 3, 2008

A full range of welding ,and cutting focus heads

LuminatorLuminator™™ Beam DeliveryBeam Delivery

Safely weld, Drill and cut aluminum, ceramic

and other reflective alloys at 90º to workpiece


December 3, 2008

Fiber DeliveryFiber DeliveryFiber Delivery

Single Fiber System

s = fiber dia. (focus fl/recoll fl)

Spot size (s)

focus lensrecoll lens


December 3, 2008

Scanner OptionsScanner Options

• The near diffraction limited beams of new laser sources (fiber, disc) make scan head delivery an ideal option.

• Features

– Latest LightningTM Digital Scanner

Technology from GSI

• High dynamic performance and

processing speeds

• Unsurpassed in beam speed and accuracy.

– to be tuned to specific applications Digital control electronics enables

scanner dynamics.


December 3, 2008

FL Galvo Head FL Galvo Head

Spot size and size of image field determined by:

• Focal length of collimating lens

• Focal length of Scan lens

• Choice of Scan Head

• Some Options

10µm spot - field 37mm x37mm

50µm spot – field 190mm x 190mm

200µm spot – field 290mm x 290mm

Larger spot possible by

defocusing


December 3, 2008

Remote Processing Remote Processing


December 3, 2008

Laser Cutting (advantages)Laser Cutting (advantages)

• Laser beam produces a spot of intense heat energy which can offer:– Narrow kerf widths with straight edges

– Very little heat affected zone adjacent to the cut edge

– Minimum heat input resulting in minimal distortion

– possible to cut/drill very fine features

• Since light exerts no force on the work piece, lasers are non-contact tools which means:– No mechanical distortion of the work piece

– No cutting tool wear, maintenance or replacement

– Ability to cut material regardless of their hardness

– Considerably less noise compared with water jet, plasma and mechanical techniques

• Additionally, the beam of light from the laser has a high degree of

control and flexibility


December 3, 2008

Laser cutting (disadvantages)Laser cutting (disadvantages)

• High capital cost relative to other techniques (however, operating costs are lower than many other techniques)

• Microcracking at the cut edge may occur in some materials (i.e. engineering ceramics etc)

• Toxic fumes are generated from laser cutting of some materials (i.e. plastics composites etc)

• Especial eye wear and enclosed working enclosures


December 3, 2008

Laser cutting mechanismLaser cutting mechanism

The beam penetrates into the kerf (a little is reflected from the materialsurface) and some passes straight through. A melt- front is generatedsupporting the molten material which is subsequently blown away out of the kerf with an assist gas.

A particular characteristic of laser cut is the formation ofStriations on the cut edge. These striations play an important partin laser cutting as they effectively control the edge roughness.

Typical assist gases are:OxygenArgon

NitrogenAir


December 3, 2008

Schematic of cutting nozzle Schematic of cutting nozzle

arrangement arrangement

• The cutting nozzle nozzle is very important part of the

cutting machine. The cut quality and reproducibility

are governed by the design of the cutting nozzle.

Basically the nozzle consists off:

• Focussing lens • Assist gas chamber

• Nozzle tip • In some cases the

nozzle also have height

sensor (auto focus head)

TTL ILLUMINATION

CAMERA

ADJUSTABLE MIRROR

RECOLL LENS

FINE FOCUS ADJUSTMENT

COAXIAL GAS FLOW


December 3, 2008

Processing dataProcessing data


December 3, 2008

Polymer compositesPolymer composites

• In general the results show:

– The fibre type had a significant influence on the cut quality, carbon reinforced materials proving to more difficult to cut

– The main problem with the carbon fibre reinforced composites was fibre/resin separation.

– The effect became more severe as the thickness of the composite increased.

– For glass and aramid reinforced composites, less separation between the fibre and resin was observed but the cut edges were still characterised by carbon deposits.


December 3, 2008

Carbon fibre compositeCarbon fibre composite

• Laser cut edge on carbon fiber (PEEK APC2) plastic composite

(0.2mm thick) showing protrusion of carbon fibers

• CO2 laser cutting conditions:

– Power: 500W

– Speed 4.5 m/min

– Assist gas: Air, 4 bar


December 3, 2008

Carbon fibre compositeCarbon fibre composite

• Example of ring cut in carbon fiber/PEEK resin 2mm thick by CO2 laser cutting.

• Laser conditions:

– Power: 950 W (pulsed)

– Speed: 1m/min

– Assist gas: Nitrogen, 4bar


December 3, 2008

Carbon compositeCarbon composite

1mm diameter trepanned hole

120µm percussion drilled hole

Entry

Exit

Low power pulsed Nd: YAG laser

Nitrogen assist gas


December 3, 2008

Polymer composites (Summary)Polymer composites (Summary)

• Work carried out at GSI and at other institutes have shown that:

• CO2 laser because of its wavelength(10.6um) is best suited for polymer composite cutting, however the cut quality is not very good:

– separation between the matrix and the fibres

– Carbon deposit on the cut edge

– Cutting process produces hazardous by- products


December 3, 2008

Ceramic materialsCeramic materials

• Ceramic and its based composites can be shaped using laser beam either by laser scribing or machining.

– Scribing is carried out at fast cutting speed (10-15m/min) to weaken the the ceramic, which is subsequently broken off.

– It is also possible to produce through- section cuts but at much

slower speeds. Both CO2 and Nd: YAG lasers are suitable for for these applications.

– Some ceramic (SI3N4 and AlC) tend to crack due to poor thermal shock. The cracking can be reduced by pre- and post heating of the

sample (typically up to 500deg C)


December 3, 2008

Silicon nitrideSilicon nitride

Processing Parameters:

• Pulsed Nd: YAG laser

• Speed: 0.75m/min

• Assist gas: Nitrogen (4 bar)


December 3, 2008

0.6mm thick Alumina (99.6%)0.6mm thick Alumina (99.6%)

Percussion drilled (50µm dia. hole)

SM 100W Fiber laser


December 3, 2008

Metal matrix compositesMetal matrix composites

• Work carried so far have shown that two distinct modes of behaviour in laser cutting of metal matrix composites:

– One appears to be where the composites behave effectively as

metals and other where fibre and resin separation occurs similar to to carbon fibre polymer composite.


December 3, 2008

Metal matrix compositeMetal matrix composite

• 2mm thick Al-Li alloy reinforced with 20% (wt) SiC particulate

– Pulsed Nd: YAG laser

– Assist gas: N2 @ 10bar


December 3, 2008

Metal matrix compositeMetal matrix composite

• 1mm thick Ti-Al- 4v alloy with SiC fibre

– Pulsed Nd: YAG laser

– Assist gas: N2 @ 10bar


December 3, 2008

SummarySummary

• CO2 laser is best suited for cutting polymer composite materials.

• Both CO2 and Nd: YAG can be used for cutting ceramic and metal based composite material.

• CO2 laser cutting of polymer composites is dependent upon the fibrereinforcement and the thickness of composite.

• For carbon fibre reinforced composites it is difficult to achieve cuts in material thickness over 4mm. In addition, separation of fibre and the resin occurs.

• Cutting of ceramic materials is affected by cracking caused by thermal shock. Use of pre/post heating can reduce this problem but some microcracking still occurs.

• In conclusion composite materials can be cut by using laser but the quality is not good as the water jet cutting.


December 3, 2008

Silicon WafersSilicon Wafers

• Silicon wafers are conventionally diced off by a thin diamond blade into individual IC chip, before they are packaged. The problems encountered in blade dicing include chipping, kerfs-loss and low productivity.

• Currently green wavelength (frequency doubled) and micro jet arebeen used but both of these processes are slow and expensive to operate.

• Milliseconds low power pulsed Nd: YAG lasers and high beam quality continuous wave fiber lasers are being used to cut thesematerials but the cut quality is poor i.e. micro cracking due toexcessive heat input, which can lead to failure of some components during process steps and associated reduction in yields.. The length of micro cracks can range from 15µm to 100µm depending on the laser source being used.


December 3, 2008

100W SM Fiber laser100W SM Fiber laser

400uµm thick polycrystalline silicon material, cutting speed > 4m/min showing very good edge

quality and no sign of any microcracking


December 3, 2008

SM Fiber laser with SM Fiber laser with

modulated outputmodulated output

1.8mm thick polycrystalline silicon material, cutting speed >0.2mm, showing slight resolidified molten material at bottom of the cut, but

no sign of any micro cracks


December 3, 2008

Pulsed Nd: YAG LaserPulsed Nd: YAG Laser

1.4mm thick polycrystalline silicon material, cutting speed

>0.3m/min, very smooth cut edge and no sign of any micro cracks

2mm thick polycrystalline silicon

material, cutting speed >0.15m/min, very smooth cut edge and no sign of

any micro cracks


December 3, 2008

Pulsed Nd: YAG laserPulsed Nd: YAG laser

Percussion drilled in 2mm thick polycrystalline

silicon material


December 3, 2008

Dr Mohammed Naeem

Laser Material Processing Development Manager

GSI Group Ltd, Laser Division

Cosford Lane, Rugby, Warwickshire, CV21 1QN, UK

Telephone (Direct Dial) : +44 (0)1788 517848

Telephone (Switchboard): +44 (0)1788 537075

Local Fax: +44 (0)1788 532617

Email: [email protected]

www.gsiglasers.com

Documents

Laser Cutting of Composites and Ceramics - AILU · Laser Cutting of Composites and Ceramics Laser processing of polymer, metal and ceramic composites ... beam either by laser scribing