Seminar Final Anand

8/18/2019 Seminar Final Anand

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LASER BEAM WELDING OF PLASTIC

A SEMINAR REPORT

Submitted by

ANAND GARG (12ME001637)

in partial fulfillment for the award of the degree

of

BACHELOR OF TECHNOLOGY

in

MECHANICAL ENGINEERING

DEPARTMENT OF MECHANICAL ENGINEERING

SIR PADAMPAT SINGHANIA UNIVERSITY, UDAIPUR

APRIL 2016

ANAND GARG/ME/SPSU/Seminar/2025-16Page 1


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BONAFIDE CERTIFICATE

Certified that this project report LASER BEAM WELDING OF PLASTIC! is

the bonafide work of ANAND GARG who carried out the seminar work

under my supervision.

(P"#$% G% D% B&''&) (P"#$% % Y% *+&)HEAD SUPERVISOR

Mechanical Engineering Department Assistant Professor

ir Padampat inghania !niversity Mechanical Engineering Department!daipur ir Padampat inghania !niversity

!daipur



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ABSTRACT.

T+ -&'" .&' / / 1604% S# . .&' + ##- +& #5"+// +& # 8&5+ 59 ./+ + 9#''/:/-/;! "illiam M. teen. #ew

possibilities are still arising as a conse$uence and cause of the laser%sincreasing reliability& decreasing price and the diversification of laser

characteristics.'he demand for consumer goods& namely& food and medical products&

to be conveniently packaged in plastic materials in order to preserve $ualityand hygiene& is constantly increasing& as are the number of packaging stylesand materials.

'he replacement of traditional tools& used to cut or weld in the plastic packaging industry (hot knives& ultrasonic heads or hot air)& by laser tools&can be justified by the increase in the reproducibility of the process (no toolwear)& simplicity of processing moving parts (no need to *stop and start a

production lines) and increase in productivity moving the laser beam over the material faster than the mechanical counterpart. #ot to mention the well+known general advantages of laser materials processing& as a non+contact&non+contaminant process& fle,ible and easy to control and automate.

'he first few communications on plastic welding by laser appeared in

the literature

in -/0& welds of low+density polyethylene sheets up to -.1mm thick wereachieved with a -22" C30 laser at speeds of -2mms4-. 5owever& it has

been during the last decade that research in this subject has seen greater

development& regarding increasing speed& new laser sources mathematicalmodelling and industrial applications. 6t is very likely that much more

proprietary industrial work has been done& but not published. 'hecomponent+conserving and clean process offers numerous advantages andenables welding of sensitive assemblies in automotive& electronic& medical&human care& food packaging and consumer electronics markets. Diode lasersare established since years within plastic welding applications


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T&:- #$ C#'

T/- P&444444444444444444444444444%% (/)

A8#.-


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LIST OF FIGURES

S"% N#% T/- #$ F/5" P& N5

0.9 Assembly of Automobile 8ight -/

0.: Material Compatibility -/

9.- E$uipment for 8ight 8aser "elding using 0:

#d?@A or C30 laser

9.0 5ybrid "elding E$uipment by 8PB7 Company 0<

:.- Principle of novel infrared radiation welding 0

procedure with a transparent heat sink

:.0 'ransmission pectra of Plastics 92

1.- alvo pyro combination 99

1.0 Melt Collapse 91

1.9 eflection Diagnosis Concept 9<

1.: Camera view of flaw 9/

1.1 Cycle 'ime Comparison 9


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LIST OF TABLES

S"% N#% T/- #$ T&:- P& N5


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1% I"#58/#

Plastic materials form such a large and varied group& characterised by so

wide a range of properties that it is now normal to call them mass material=. 6t

is difficult to conceive of plastics being substituted for by other materials. 6n

certain circumstances& this group of materials is a substitute for traditional

materials& such as steels and non+ferrous metals. 'he high level of e,perience

that is associated with current methods of manufacture of semi+fabricates in

plastic materials provides designers with unlimited possibilities to produce new

products& often of complicated shapes. Modern bonding methods& such as laser+

welding& make it possible to widen the range& and this in turn& gives a chance to

free selection of shape to be made& and properties of new product to be

developed.

'he constantly growing utilisation of plastics in the industry creates new

possibilities for constructional solutions& lowering of cost and mass of fabricates& and also for the rising of durability levels& resistance to corrosion and

action of many chemical agents (5yla 022:). All of the above listed factors lead

to call for more plastics and for their participation in the world=s production of

constructional materials to rise at a high rate (see 7igure). 3ver-222 various

types of such materials are currently available on the world markets. 7rom the

point of view of bulk& they constitute over half of the production of steels.According to data produced in 0222& the use of these materials in the world in

-9 amounted to 2 m tons. 6t rose in - to about a -22 m& and is e,pected

to reach over -02 m tons by 0202 (Fuchowska 0222).

6n line with the popularisation of plastics as constructional materials

comes the development of bonding methods and the provision for selection of

welding techni$ues correct from the point of view of the level of yield and the


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economy of bonding.

'he need for effective and reliable bonding methods and re$uirements for

improved $uality of products are undoubtedly reasons for the development of

new processes of bonding plastics (oron 0222)& which also include laser+

welding. #ot only does this method provide high efficiency& the highest possible

levels of $uality and strength of bonds& but also the maintenance of high

manufacturing precision and cleanliness of the joint area.

7ig -.- ? "orld=s demand for selected constructional materials (5yla

022:).


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'he laser welding of plastics is the advanced technology of joining of sheets&

films or shaped components produced from polymers in heating with the

focused beam of laser radiation. 8aser welding was demonstrated for the first

time in the -/2s and has been regarded for many years as an e,pensive process

in competition with the conventional technologies of joining of components.

#evertheless& since the middle of the -2s& laser technology has been widely

accepted as a result of advances in the area of laser methods.

'he laser welding systems are most efficient in the applications in which

the welded components re$uire careful handling (electronic components) or sterile conditions (medical tools& packing of food products& etc.). 'he very high

speed of laser welding makes this method especially valuable in applications in

the assembly lines of plastic components. 8aser welding


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can also be used to join components with complicated geometry which are

difficult or impossible to weld by other methods. Engineers often note special

advantages of laser technologies which will result in the active growth of the

number of industrial applications G the absence of contact of welding e$uipment

with the welded componentsH very low labour contentH the possibility of joining

materials of different composition and colourH high $uality of welded jointsH

only slight heating of components and minimum deformationH possibility of

welding in areas of difficult access and different spatial positionH simple

automation and robotiIationH efficient use of electric energy and filler materialsH

comfortable working conditions and ecological efficiency.

8aser welding is used e,tensively in electronics in assembling keyboards

for different systems& mobile telephones& a large number of contact devices& etc.

and also in the car industry in the production and assembly of automatic door

locks& devices for keyless access& heating models& the bodies of transmissions&

sensors of sections of engines& the bodies of the driver cabins& the oil tanks of the hydraulic systems& filter casings and many other systems. 6n medicine& laser

welding is used for assembly of containers and filters for li$uids& joining of

pipes& bags for patients with intestinal problems& implants and micro jet

elements used for analysis& etc. 'he technology of melting the edges of thin

plastic films for hermetic packing items is used widely.

8aser welding of plastics is a very young= technological process. As a

result of the development by technologists and also rapid advances in laser

technology& the methods of laser welding are being constantly improved. 'he

authors of the present article have already discussed this subject many times. At

the same time& it is believed that the laser welding of plastics is an independent

section of laser technology and has a considerable scientific and industrial

potential. 6t is therefore convenient to consider separately in this article the


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current state and dynamics of investigations and developments and also the

prospects of this advanced technological process.

T"&//#&-


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the same type can be welded because every type of plastic material has its own

typical molecular structure and welding temperature. 'he joining of plastics by

welding takes place if the three constant conditions are fulfilled?

.

5igher temperature which should reach the level of the viscous+fluid state

of the welded materials. 'he transition of the polymer to the viscous+fluid

state should not be accompanied by thermal degradation of the material.

Every plastic melts within a specific temperature rangeH


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.

'ight contact of the welded surfaces. Pressure enables the molecules of

the plastics to mi, with the formation of the welded joints. 'he $uality of

the welded joint decreases when the pressure is reduced below or is

higher than the optimum pressure for every pair of materialsH

.

3ptimum holding time because the plastic material re$uires a certain

period of time for melting and a certain period of time for cooling. 6t

should be mentioned that the temperature coefficient of linear e,pansion

of plastic materials is several times higher than that of the metals and&therefore& welding and cooling are accompanied by the formation of the

residual stresses and strains which reduce the strength of the welded

joints in the plastics. 6n this case& acceleration of the welding process may

cause higher stresses in the region of the welded joint.

'here are a large number of systems for welding plastics on the market but no

universal

welding technology is available.


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LASER PLASTIC WELDING

2%1F5&


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'ransmission laser welding is based on the physical effect in which

many polymers efficiently absorb radiation in the near+infrared range. A

relatively narrow wavelength range (>22J0222 nm) is used for welding.

!sually& the components to be welded are placed in a clamping device

which compresses the components together with ma,imum force. 6n the

conventional device& the material of the component which is the first to be

affected by the beam is selected to ensure that it transmits ma,imum radiation

(7igure -). 'he material of the second component should be capable of

absorbing laser radiation. 'he laser radiation beam passes through the first

(transparent=) component and is absorbed by the material of the second

component of the joint generating a large amount of heat. ince both the

components are tightly pressed to each other& the heat is transferred from the

absorbing layer to the transmitting layer and heats both components. 'he thin

layers of the plastic& situated on both sides of the joint& melt& mi, together and

form strong joints during cooling. 'he main critical process parameters are

temperature& holding time and pressure.

'he energy density re$uired for welding is associated with the

temperature of the component and the duration of the process and is determined

by the laser power& the siIe of the working spot of radiation on the component&

the radiation time (for stationary processes) or welding speed (in the processes

with relative displacement of the components). 'he energy density in this case is

proportional to the radiation power and inversely proportional to the area of the

focused beam on the processed surface and the speed of travel of the beam in

relation to the surface.

6f the level of laser radiation energy in the welding Ione is not sufficiently

high& heating may prove to be insufficient and& correspondingly& the welded

components are not held for a sufficiently long period of time in the heated state


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for the formation of a strong joint. 3n the other hand& in e,cessive heating the

polymers may degrade in the joint Ione resulting in the formation of porosity&

charring or burning. 6n practice& there is a wide range of conditions for each

specific joint in which the joints of acceptable $uality form. 'he majority of

polymers are welded using an laser energy density in the range of 2.-G 0.2

;Kmm0. egardless of the fact that the energy density in the welding Ione can be

used to characteriIe the process& many authors believe that this correspondence

is only conditional. 'he heat transfer from the welding Ione in the welding

process should be taken into account and this makes the process non+linear. 'his

means that the application of the same energy density results in the same $uality

of the welded joint. 7or e,ample& at a constant siIe of the focused radiation

spot& doubling the radiation power


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usually increases the welding speed by more than -22L whereas the welding

characteristics remain the same?

where Ew is the radiation energy supply to the welding IoneH P is the laser

radiation power in the vicinity of the welding Ione& and v is the speed of travel

of the beam in relation to the welded components.

6n cases in which the welded plastic components are not compressed to each

other or the compression pressure is not sufficiently high& the contact between

the components is not sufficiently tight. 'his may result either in inefficient heat

transfer from one component to the other or in limited mutual diffusion of the

polymer chains on both sides of the joints. 6n both cases& the strength of the

welded joint is reduced. 'herefore& reliable clamping and securing of the

welded components in the weld Ione is an important technical condition. 'he

clamps

7ig 0.0 ? Methods of welding plastic components? (a) with the moving

object in weldingH (b) with the moving beamH (c) with the fans shapeddistribution of radiationH


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(d) simultaneous (synchronous) welding around the perimeter (contour)and (e) with the scanning radiation beam.

8aser welding is used for joining components of different shapes& siIe

and configuration. 'here are several main methods of laser welding differing in

the methods of generating the forces in the range of 2.-G-.2 #Kmm0 are used in

most cases. 'ransmission welding using #d?@A or diode lasers has been used

to weld successfully the plastic components more than -mm thick at a linear

welding speed greater than 02 mKmin. 'he welding speed in welding of films

using C30 lasers can be even higher& up to /12 mKmin& although technologists

fre$uently mention the restrictions of carbon dio,ide laser. relative displacement

of the welded components and the laser radiation beam (7igure 0).

At a stationary radiation beam& the components to be welded are moved to

produce a continuous joint (7igure 0(a)). 6n most cases& this displacement is

produced using a table with movement along one or two coordinates and can be

easily programmed. 'his method is used only in cases in which welding in three

coordinates is not re$uired.

'he optical system for the radiation beam& supplied by the optical

waveguide& or the head of the diode laser can be installed in robotiIed

e$uipment& including the three coordinate systems of the hand. 6n these cases&

the laser or the final element of the optical system travels along the trajectory

(the contour) corresponding to the future welded joint. 6n welding along the

contour& the layers are gradually welded by the laser beam which travels and

melts the material along the welded joint. 6n a different variant of this welding

system& the components& compressed to each other& travel in relation to the

stationary laser beam. 6n the automatic systems& the displacement of the laser

beam is often combined with the displacement of the components. 6n


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synchronous welding with several beams& the laser radiation from& for e,ample&

several laser diodes is directed to the contour line of the welded joint which is to

be welded resulting in simultaneous melting and welding of the entire profile

(7igures 0(b) and (d)). 3ne of the varieties of this welding method is based on

the radiation of a single laser split into several separate beams which are

subse$uently applied together on the component to improve the strength of the

effect. 6n some cases& it is recommended to use $uasi+synchronous welding &

which is based on the combination of welding around the contour and

synchronous welding. 'he mirrors direct the laser beam at a high speed (at least

-2 mKs) along the component which is to be welded. 'he entire contour of the

component is then gradually heated and melts.


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"elding with a template is slightly different. 6n this welding method& the

laser beam is applied to the component through a specially produced template

which does not cover small& precisely defined areas of the underlying plastic

layers which will be melted and bonded.'he method can be used for producing

precision joints with a high resolution& up to -2 mm.

6n cases in which the laser power is ade$uate& welding is carried out with

the fan+shaped distribution of radiation in which laser radiation is distributed in

a flat diverging beam and forms a line on the surface of the component (7igure

0(c)). During welding& the beam or the component travels in a specific direction.

Masks which protect sections of the component that should not be subjected to

radiation are used in some cases. 'his method is often used in two dimensional

welding of small components with the complicated configuration of the welded

joint.

6f it is re$uired to produce a large number of identical short welded jointsor weld spots& it is recommended to use the matri, of diode emitters which is

shaped according to the shape of the component and assembled taking into

account the number of welded joints. 'his method& which is used if

simultaneous laser radiation is to be applied along the entire length of the joint&

is usually automated. 'his is carried out using basic e$uipment for ultrasonic

welding in which laser technology efficiently replaces the ultrasonic process in

the technology of joining components sensitive to vibrations and where high+

$uality welded joints are to be produced. 'he technology of simultaneous

welding permits both two dimensional and three+dimensional configuration. A

particular advantage of this method of laser welding is the larger allowance for

the welding operation.

'he laser radiation beam in welding with scanning (7igure 0(e)) is

deflected by two orthogonal mirrors controlled by the direction of propagation


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of the beam in space. 'he working Ione in the systems of this type has the

transverse dimensions from 12 , 12 to -222 , -222mm in two+dimensional

welding. enerally speaking& the main problem when increasing the treatment

area is the appropriate increase in the difference of the working path of the laser

beam so that it is necessary to under focus= the beam. An efficient method of

coordinating the focusing of the beam in different areas of the treated surface is

the application of several scanning optical systems& and the combination of the

systems increases the length of the treatment Ione. As in simultaneous welding&

these welded joints overlap the entire joint Ione

and are characteriIed by high shrinkage of the material and potentially

larger welding

allowances.


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'able 0.-? Comparison with onding


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2%2 L&'"' 5' $#" .-/ 9-&'/8'

everal main types of lasers are used in industry for welding of plastics at

the present time. 'hese include C30 lasers& solid+state lasers (with lamp or

diode pumping) and fibre lasers. ecently& high+power diode lasers have also

been used widely in certain areas of production.

'able 0.0? main technical characteristics of the individual lasers used for

welding plastics

C30 lasers are used at a wavelength of -2.< mm in the infrared range.

!sually& these lasers generate a beam of highly collimated radiation with a

diameter from several millimetres to several centimetres. A significant

shortcoming of the C30 lasers (like of any gas laser) is the low efficiency (the

radiation power& related to the electrical power in pumping) resulting in high

production costs. 'he second shortcoming of the powerful gas lasers is their

large dimensions. oth factors introduce a number of restrictions on use in the

actual technological process. 6n addition to this& the radiation of C30 lasers

cannot be sharply focused because of the multimode structure and large

wavelength of radiation (laser radiation of the majority of lasers) and& therefore&

e$uipment based on C30 lasers is used mainly for welding of films.


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'he collimated radiation beam at the e,it of the solid state lasers& where

the pumping of radiation from the lamp or a group of light diodes is focused

injected into the laser bar or discs& has the wavelength in the near+infrared

region (usually -.2


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are characteriIed by the compact form& the relatively low initial price and

service costs& high efficiency (up to


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company& these bags were assembled by manual gas welding.

As an alternative to traditional welding& transmission laser welding

was selected in the moderniIed process. 6n designing new technology& it was

important to take into account two essential re$uirements? the strength of the

joint should not be lower than in standard gas welding& and the joint should be

leak tight. Previously& the bags were produced from natural polypropylene. 'o

increase the technological parameters of the new process& including laser

welding& the edges of the end sheets were produced as previously from the same

polypropylene which is transparent to laser radiation in the near+infrared regionof the spectrum& whereas the transverse sections of the bags are pressed from

polypropylene sheets which efficiently absorb laser radiation. 'he welded

joints& produced by the new technology& have the same strength as those

produced by the standard technology G no failures were detected in the welded

joints in both cases. 'he new process greatly simplifies the design of the

transverse sections and produces efficiently leak tight joints. ubse$uently& the

process was automated and introduced into the production cycle.

At the present time& the bags are welded by a robot of Motoman

company with si, degrees of freedom& controlled by a diode laser manufactured

by 8aserlines. 'he components are secured and compressed using a ring shaped

sliding clamp controlled by a pneumatic drive.

8aser welding of identical plastics showed the highest efficiency in lap

welding of thermoplastic films.

'he application of laser radiation for joining the reinforced thermoplastic

composites offers new possibilities for overcoming the shortcomings of the

traditional technologies. 6n this case& laser welding is ecologically clean because


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no chemical additions or adhesives are re$uired. 'he accuracy& fle,ibility of

laser technology and also the high+$uality welded joints are already utiliIed in a

large number of industrial applications.8aser transmission welding has been

introduced in the industry in the manufacture of thermoplastic composites with

short fibres& where the laser efficiently replaces welding with a hot air jet. 3f

special interest in recent years has been the possibility of welding reinforced

composites with the long fibre structure (long fibre reinforced thermoplastic

composites 87'PC G thermoplastics with the fibre length greater than < mm).

'he authors of developed technical fundamentals of laser technology utiliIing

the natural properties of the material. 'he new technology is based on the layer

welding and the mechanical characteristics of the welded joints were

determined. 'he test results show that laser welding is a superior and highly

promising technology for joining many combinations of materials used in the

automobile and aviation industries and is characteriIed by considerably better

ecological parameters and safety of the processes in comparison with the

conventional adhesive bonding technologies.

'able 0.9? "eldability of different plastics


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2%= ?#// #$ /''/


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regularly updated website www.laserplasticwelding.com maintained by the

enthusiasts and professionals in laser welding technology.


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7ig 0.9 ? Assembly of the automobile light (by the method of laser welding usina glass sphere which focuses the laser beam and also acts as the clampingdevice).

7ig 0.: ? Material Compatibility Chart


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2%> W-/ #$ "&'9&" 9-&'/8'

!ntil recently& in the introduction of welding technology it was necessary

to use standard materials& and in the majority of cases both welded materials

were visually non transparent. 'he technological restriction of transmission

laser welding G the upper layer (component) should be transparent to laser

radiation G and the lower layer G should absorbs laser radiation& considerably

limited the design possibilities. 6n transition to laser technology& this usually

included the change of the material to a suitable material or addition of a dye to

the plastic to increase its absorptivity. At the same time& for e,ample& in the

medical industry& today are a large number of tasks in which one or fre$uently

both welded components should be transparent. 'his circumstance has greatly

restricted the areas of application of laser technology. 'herefore& in many

processes of this type it has been necessary to develop a welding technology

without using additional absorbing materials. 5owever& such materials are either

very e,pensive or have different colour shades which are not acceptable in

components.

A breakthrough in the welding of transparent plastic was made by the

ritish company '"6 which reported the development of a new technology in a

patent in 0229. Clearweld 'echnology is based on the application of plastic

materials with a high absorptivity as the laser radiation wavelength (and at the

same time the minimum absorptivity in the visible range of the spectrum). 'his

approach can be used to produce welded joints with the minimum effect on the

e,ternal appearance of the component& and offers considerable fle,ibility in the

selection of materials and colours. 'he absorbing material is represented by an

additional coating or the lower layer of the welded pair.

Many systems of pair plastics with the selection of appropriate colours


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providing further possibilities for designers have been developed. 'he only

condition in the pair is the coincidence of the visual colour and the large

difference in the absorptivity of the radiation wavelength of the working laser.

'he very first application of the method was welding of two visually black

materialsH at the present time& a large number of systems of pairs& including

white materials& are available. 'he project Poly right awarded to the scientific

and research organiIations of the European Community countries has been

formulated for detailed investigations of laser welding of polymers and for the

development of technological conditions of high speed and fle,ible industrial

laser technologies. 'he key aspect of the project


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is the e,tensive application of the fibre lasers with the power of up to 122"

which can be used to optimiIe not only the thermal parameter of the welding

process but also the wavelength to increase the efficiency and speed in welding

and the $uality of the joint.

#ew laser welding systems have been developed& the resolution of technology

has been improved by using dynamic masks in high+fre$uency scanning

systems for transporting and focusing the beam.

'he e,perimental results show that the most promising results in laser

technology can be obtained by selecting laser radiation with the wavelength atwhich the welded plastics have the re$uired properties.

'he latest technology and prospects for laser welding without absorption

of radiation on the e,ample of the components of transparent PMMA polymer

films using the accurate selection of the wavelength of laser radiation and

radiation techni$ues have been published in research.

egardless of the completely different physical principle of welding& the authors

have managed to obtain the highest technological parameters of the process.

'he welding speed reached up to -22mmKs at the laser radiation wavelength of

-112& -/22 and -2> nm. 'he best spectrometric results have been obtained at

the radiation wavelength of appro,imately -/22 nm which is used by many

fibre lasers. 'o supply the radiation to the weld boundary of the transparent

materials& the authors developed a special lens optical system in which the focal

point is situated at the interface with high geometrical accuracy.

2%6A&&@

-. 8ower ;oining Cost

0. Minimal Part tress

9. ;oint trength:. 9d Comple, hapes


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1. #o Particulate Development


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'he automotive industry created the foundation for laser welding. 'he

original use was welding housings for electronic components. A simple task& but

as electronics become more prevalent in cars (approaching 91L of the total cost

of a vehicle) protecting those electronics is becoming increasingly important.

A stress free& reliable and highly monitored process allows for tightly

sealed housings& with no additional material costs and a near perfect reject rate.

'he high volume applications in the automotive industry clearly benefit from

such a process.

'he fle,ibility of laser welding does not stop there. 'hrough the use of

robots& laser welding was able to e,pand its abilities in the automotive industryto include lamp welding. Clean& strong joints have been sought after for

automotive lamp assembly ever since plastics

replaced glass for e,terior lighting. 8aser welding is a stress free process and

clean& aesthetically appealing joints are easily achieved. ut& possibly even

more important is its ability to work on large& free+form shapes with comple,

curves& a vice of most traditional welding methods.

3ther applications in the automotive industry include welding of

instrument panels& keyless entry remotes and even fuel tanks.

M/8&-

'he medical device industry is $uickly growing& re$uiring joining of

plastic devices ranging from catheters to microfluidic devices. 'he surgical

nature of laser plastic welding makes it well suited to handle the delicate

devices and precision joining.

esides hermetic seals and a high precision re$uirement& medical devices

often re$uire perfectly clean joints. 'his task is often difficult for other joining

methods. Adhesives can cause contamination& especially at the micro level

where many of these devices are operating and traditional welding methods

such as ultrasonic and vibration leave dust+like particulates behind that can also


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contaminate the device.

C#'5


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8aser welding of plastics is a highly specialiIed technology of joining

components which can be used most efficiently in applications re$uiring high+

speed welding and welding of brittle components or components re$uiring

sterile conditions. 'he laser beam welding often has technological advantages in

comparison with the traditional technologies of welding components. ervice

e,perience shows that industrial e$uipment for laser welding of polymers has a

number of special practical

Advantages

high+$uality welded joints and the possibility of producing leak tight

jointsH

the possibility of packaging components sensitive to vibration because

the components do not move during weldingH

reduction the degree of distortion of the components in welding of heat+

sensitive components because the siIe of the heat+affected Ione is smallH

reduced contamination of the environment and reduced amount of

welding fumes because the molten material is situated inside the joint and

is in contact with the e$uipmentH

reduced energy re$uirement because laser radiation is focused only in the

Ione of the formation of the welded joint and only the small volume of

the polymer is remelted so that the efficiency of the process is very highH

the high degree of automation of the process resulting in higher $uality of

the components and reproducibility of the resultsH

7le,ibility of the process and e$uipment G the laser system can also be

used in other production lines.


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Comparison with C30 arc "elding?

6n comparison to C30 gas arc welding& 8" can significantly reduce the

welding deformation

'he range with high longitudinal tensile stress in the joint welded by

8" is significantly narrower than that generated by C30 gas arc

welding. Moreover& the ma,imum value of longitudinal residual stress

generated by the former is smaller


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than that caused by the latter.

8aser welding of plastics is an established process that is used in more and more

applications in different markets and is increasingly displacing the traditional

welding methods. 6n medical device manufacturing& for instance& cleanliness is

absolutely mandatory. 5ence& laser welding is particularly well established in this

market. 6n the automotive supply industry the parts are e$uipped with sensitive

electronic components or guide and contain fluid + here laser beam welding is the

method of choice. 6n combination with process control& the diode laser will make

its way to a variety of future applications.

'he use of lasers in the industry for the bonding of plastics has increased in

last decades. According to the literature (5erIinger& chloms -1)& some 01L of

the industry employing lasers is concentrated in ;apan. 'his is due to the

development of the industry and economy of that country. 6t is e,pected that in the

future some -2L of all of the joints in plastics will be laser+produced (rande

022:).

'he laser technology offers novel solutions that permit to off+set limitations&

often imposed by conventional methods. 'echnological progress that has taken

place in last years and the re$uirements that the development of the industry poses

indicate that this technology of bonding plastics will further develop.



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=%R$"8'

-. .N. Moskvitin & A.#. Polyakov E.M. irger (02-9) 8aser "elding 3f

Plastics (eview)& "elding 6nternational& 0/?& /01+/9:& D36?

-2.-2>2K212/--0

0. A. "eglowska (022>) Modern methods of laser+welding of plastics& "elding

6nternational& 00?0&-22+-2:& D36? -2.-2>2K212/--2>2-2>-

9. Andor auernhuber 'amOs Markovits (02-:) 5ybrid joining of steel and

plastic materials by laser beam& 'ransport& 0?0& 0-/+000& D36?

-2.9>:1::1

:. 7. uadrini & 8. anto 7. 'rovalusci (022>) Diode 8aser "elding of

Polyethylene& Polymer+Plastics 'echnology and Engineering& :/?/&


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