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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
ANAND GARG/ME/SPSU/Seminar/2025-16Page 2
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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.
ANAND GARG/ME/SPSU/Seminar/2025-16Page 41
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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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