Series welding processes for plastic components
Process description
In the case of hot gas butt welding, the heat is input by means of convection and heat conduction. In this respect, the joining faces are plastified by a hot gas jet which emerges from a hot gas nozzle system adapted to the joining part. The process gas can be chosen freely but is selected depending on the oxidation susceptibility of the plastic to be welded. The gas temperature substantially above the melting temperature may lead to thermal or thermal-oxidative damage to the plastic. As in the case of heated tool and infrared welding, the heating and joining phases are carried out separately from each other. After the desired melt layer has been produced, the hot gas tool is removed from between the components which are welded under pressure. The characteristic process parameters are the gas temperature, the volumetric gas flow, the distance between the nozzles and the component surface, the heating time, the joining pressure and the cooling time. The joining process can be carried out with displacement control or force regulation.
Areas of application
Hot gas butt welding is a fully automatable welding procedure which is basically suitable for all thermoplastic mouldings. It offers the possibility of reliably welding three-dimensional joining faces. Above all, automobile construction components with which complete freedom from particles is demanded are regarded as examples of applications. It is possible to join not only intake and charge air pipes and fuel and hydraulic oil tanks but also headlights.
top component
hot gas tool
bottom component
Advantages Disadvantages
contactless heatingthermal / thermal-oxidative damage to the plastic possible
homogeneous welding bead (particle-free)
energy input outside the joining zone possible
suitability for complex component geometries
few scientific foundations
suitability for high-temperature plastics
high operating costs
medium to long process times needed
Hot gas butt welding
Process description
In the case of ultrasonic welding, the high-frequency energy produced in a generator is transformed into high-frequency mechanical oscillations by a sound transducer (converter) and is transmitted to the component by the welding tool (sonotrode). In this respect, the entire oscillation system (consisting of the converter, the transformation piece and the sonotrode) works in resonance. In the case of ultrasonic welding, the working frequency is typically between 20,000 Hz and 40,000 Hz. The heat needed for the welding is produced by the dissipation of the mechanical oscillation energy in the joining zone. In this respect, the high-frequency oscillations are absorbed and lead to molecular and interfacial friction and, as a consequence of this, to the plastification of the plastic. In the case of ultrasonic welding, a special joining zone geometry in the form of an energy director (ED) is necessary for targeted energy input and for weld formation appropriate for the application. The parameters which are particularly relevant to the process are the working frequency of the ultrasonic welding machine, the oscillation amplitude, the joining pressure or the joining pressure profile and the hold time. The welding process can be carried out with displacement control, time control or energy regulation.
Areas of application
Typical areas of application are the automobile, packaging and electronics industries as well as medical technology. Because of the very short process times, ultrasonic welding is outstandingly suitable for utilisation in series production. As a consequence of the size restriction on the welding tool, the procedure is suitable particularly for small to medium-sized components made of thermoplastics as well as for the welding of films and non-woven materials.
Ultrasonic welding
Advantages Disadvantages
very short process times
special joining face design (ED)
high degree of automation possible
high material and geometry dependence
energy-efficient and resource-conserving
oscillation input into the component
low investment costs particle abrasion
shortest process times needed
converter
sonotrode
amplitude transformer(booster)
Vibration welding
Process description
In the case of vibration welding, the plastic is heated by the dissipation of friction. With the effect of a joining force, the joining parts are moved relative to each other with an amplitude in the horizontal direction. In this respect, electromagnetic spring systems initiate horizontal oscillations in the top table. The interface between the joining parts is plastified by the transformation of friction energy into heat. This results in a melt layer which is exposed to alternating shear loads by the vibration movement. This gives rise to an additional energy input. Due to the applied joining pressure, melt is pressed into the bead at the same time. Consequently, this constitutes a single-stage welding procedure. With regard to the process management in the case of vibration welding, a distinction is made between the linear/longitudinal and linear/transverse oscillation directions (longitudinal and transverse to the main expansion direction of the joining parts respectively). The characteristic process variables are the oscillation frequency, the oscillation amplitude, the joining force, the joining path and the cooling time. The welding process can be carried out with time or displacement control. In addition, there is the possibility of another substantial reduction in the process time in the case of vibration welding using the process management strategy of the so-called high-pressure approach.
Areas of application
Vibration welding is suitable for the welding of injection-moulded, extruded or blow-moulded components in series fabrication. It is also possible to weld different materials with each other (e.g. plastic with elastomers, textile fibres or wood materials). The main areas of application are the automobile and household appliance industries.
Advantages Disadvantages
short cycle timesplane weld contours required
high weld quality
limited suitability for components with integrated electronic components
robust installation technology
particle abrasion (fluffing)
tolerant to contaminations
limited suitability for flexible components
short process times needed
top component
bottom component
joining path
joining force
joining force
amplitude
Laser transmission welding
Process description
The joining zone is heated and plastified because the electromagnetic energy of the infrared laser radiation is absorbed by the plastic. In the case of laser transmission welding, the joining parts are brought into contact before the welding and the laser beam penetrates the joining part transparent for it and is transformed into heat in the absorbing joining part. The laser-beam-transparent joining part is also heated by heat conduction. Thus, the weld is manufactured by applying a joining pressure. In the case of laser transmission welding, it is possible to bridge only very small moulding tolerances since a gap prevents the heat conduction into the transparent component. A distinction is made between contour welding, simultaneous welding, quasi-simultaneous welding as well as mask welding. The relevant process parameters include the type of laser beam source, the wavelength, the energy per unit length as well as the properties of the spot.
Areas of application
The main utilisation fields can be found in the electronics industry, medical technology and the automobile industry. Apart from identical plastics, different plastic types can also be welded with each other in so far as their melting temperature ranges coincide sufficiently and both materials are chemically and physically compatible.
Advantages Disadvantages
small, easily controllable heat-affected zone
limited possibililty of gap bridging in order to compensate for fabrication tolerances
optically high-quality welds (no squeeze flow in the case of contour welding)
cost-intensive installation technology
short cycle timescomplicated protective measures
usable for very small and precise components
as a rule, the laser beam must be able to pass through one joining member
short process times needed
Laserstrahl
transmittierender Werkstoff
absorbierender Werkstoff
Wärmeeinflusszone
Schweißnaht
Laserstrahl
transmittierender
Werkstoffabsorbierender
Werkstoff
Wärmeeinflusszone
Schweißnaht
Laserstrahltransmittierender Werkstoff
absorbierender Werkstoff
Wärmeeinflusszone
SchweißnahtLaserstrahl
transmittierender Werkstoff
absorbierender Werkstoff
Wärmeeinflusszone
Schweißnaht
weld seamlaser beam
heat-affected zone
absorbing material
transmitting material
Process description
In the case of hot tool welding, the joining faces of the mouldings or the semi-finished products are heated by the direct contact to the tempered heated tool and are subsequently welded under pressure. Because the heating and joining operations are carried out at different times, heated tool welding constitutes a multistage procedure. The process is divided into five process phases: alignment, heating, changeover, joining and cooling. During the alignment, the joining faces come into complete contact with the heated tool. Subsequently, a melt layer forms with nearly pressureless heating. Thereafter, the heated tool is removed (changeover) and the components are welded under pressure. After the needed joining path has been covered and the melt has thus been pressed out, the cooling operation takes place under pressure and the melt solidifies. The welding process can be carried out with pressure regulation or displacement control. The characteristic process parameters include the heated tool temperature, the heating time, the joining pressure and the cooling time.
Areas of application
Heated tool welding is one of the dominant joining technologies in the series fabrication of semi-finished products and mouldings made of thermoplastics. This procedure is characterised by the particular suitability for complex three-dimensional joining faces and the applicability to a large number of plastics. The heated tool butt and socket welding procedures are extremely significant for welding in the pipe and apparatus construction sectors.
top component
heated tool
bottom component
Advantages Disadvantages
high degree of automation possible
complicated tools for 3D structures
high degree of maturity long cycle times
homogeneous welding bead (particle-free)
material adhesion to the heated tool possible
tolerant in the case of material differences
high running costs (energy)
medium to long process times needed
Heated tool welding
Process description
In the case of infrared welding, the heat is input by means of heat radiation. The radiation emitted by the infrared radiator is absorbed by the plastic to be welded. As a rule, the short-wave (0.78 - 1.4 µm) and medium-wave (1.4 - 3 µm) infrared radiation ranges of the light spectrum are applied in this respect. In order to achieve a high efficiency, the emission spectrum of the radiator should be coordinated with the absorption spectrum of the plastic. It must be borne in mind that any filler materials (e.g. carbon black or colour pigments) alter the absorption capacity. A distinction must be made between volume and surface absorption. When short-wave infrared radiators with mostly higher area capacities are used, attention must be paid to any possible thermal damage to the component surface. The process management in the case of infrared welding is similar to that in the case of heated tool welding. After the contactless heating, the infrared radiator is removed from between the components which are subsequently welded under pressure. The parameters characteristic of the process include the radiator type and power, the radiation exposure duration, the radiator distance and the cooling time. The welding process can be carried out with pressure regulation or displacement control.
Areas of application
Infrared welding is utilised across different sectors. Typical applications are the welding of pipes and large-volume tanks as well as series fabrication in automobile construction. Infrared welding is extremely suitable not only for applications with stringent purity requirements but also for the joining of high-temperature thermoplastics with and without fibre reinforcement (no danger of adhesion or abrasion). Depending on the utilised radiator system, it is possible to weld complex 3D geometries too. Moreover, the infrared technology can be combined with other welding procedures. One typical application is vibration welding in combination with infrared preheating in order to reduce the particle formation.
top component
infrared lamp
bottom component
Advantages Disadvantages
contactless heatingcomplex radiator/material dependence
high design freedom of the joining faces and the infrared radiator
coordination of the emission and absorption behaviour
homogeneous welding bead (particle-free)
energy input outside the joining zone possible
low-stress jointspossibly complex radiator construction
medium to long process times needed
Infrared welding
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Plastics Welding Technology in Perfection
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© DVS Media GmbH, Düsseldorf
The poster contents were compiled by employees of the Professorship of Plastics of the Technical University Chemnitz and employees of the KTP (Kunststofftechnik Paderborn) of the University Paderborn.
JOINING PLASTICS – FÜGEN VON KUNSTSTOFFEN
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Topics of the Peer-reviewed Papers
Quality monitoring of laser-beam-welded tapes
made of fibre-reinforced plastics by means of ther-
mography
Laser transmissio
n welding of transparent plastics
Quantification of the material damping properties
using the mandrel melting-in test
Laser beam microwelding of transparent plastics
www.fuegen-von-kunststoffen.de
www.joining-plastics.info
JOINING PLASTICS
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Qualitätsüberwachung laserstrahlgeschweißter Tapes
aus faserverstärkten Kunststoffen mittels Thermografie
Laserdurchstrahlschweißen transparenter Kunststoffe
Quantifizierung der Werkstoff-Dämpfungseigenschaf-
ten mittels Dorneinschmelzversuch
Laserstrahlmikroschweißen von transparenten
Kunststoffen
VON DER PROJEKTIDEE
ZUM PROTOTYPEN?
CHWEISV STI
EFFEKER EFFIZI
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Warmgasschweißgeräte
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joining_plastics210x150_Layout 1 25.01.2019 13:59 Seite 1
1⁄2019
Themen der Fachbeiträge
� Fügetechnologien in der Luftfahrt
� Untersuchungen zur Dimensionierung der
statischen Auszugsfestigkeit des Schraub-
blindniets
� Hybridfügen von Metall und Kunststoff
� Langzeitbelastung von Ultraschallschweißver-
bindungen – Einfl uss zyklischer Lasten
Topics of the Peer-reviewed Papers
� Joining technologies in aviation
� Investigations into the dimensioning of the
static pull-out strength of the screwed blind
rivet
� Hybrid joining of metal and plastic
� Long-term exposure of ultrasonic welded
joints - Infl uence of cyclic loads
www.fuegen-von-kunststoffen.deww.joining-plastics.infoJOINING PLASTICS
FÜGEN VON KUNSTSTOFFENSupported by
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Fax: +49 2224 90175 03
HSK Kunststoff Schweisstechnik GmbH
Zilzkreuz 1D-53604 Bad Honnef
Germany
Anz_210x150_Layout 1 20.04.2015 18:37 Seite 1
2 ⁄2019
Themen der Fachbeiträge
Evaluierung von Strahloszillationsmustern beim
quasi-simultanen Laserdurchstrahlschweißen
Reaktive Multischichtsysteme zum Fügen von
Kunststoff- und Hybridverbindungen
Inline-Überwachung der Klebstoffaushärtung
mit berührungslosem Ultraschall
Laserdurchstrahlschweißen transparenter
Kunststoffe – Teil 2
Topics of the Peer-reviewed Papers
Evaluation of beam oscillation patterns during
quasi-simultaneous laser transmission welding
Reactive multilayer systems for plastic and
hybrid joints
Inline monitoring of the adhesive curing with
contactless ultrasound
Laser transmission welding of transparent
plastics – Part 2
www.fuegen-von-kunststoffen.de www.joining-plastics.info
JOINING PLASTICS
FÜGEN VON KUNSTSTOFFEN
Supported by
7499
9
FÜGEN VON KUNSTSTOFFEN
7499
9
3-4/2018
Topics of the Peer-reviewed Papers
Quality monitoring of laser-beam-welded tapes
made of fibre-reinforced plastics by means of ther-
mography
Laser transmissio
n welding of transparent plastics
Quantification of the material damping properties
using the mandrel melting-in test
Laser beam microwelding of transparent plastics
www.fuegen-von-kunststoffen.de
www.joining-plastics.info
JOINING PLASTICS
JOIN
ING
PLA
STIC
S -
FÜG
EN V
ON
KUN
STST
OFF
EN
3-4
/18
Supported by
Themen der Fachbeiträge
Qualitätsüberwachung laserstrahlgeschweißter Tapes
aus faserverstärkten Kunststoffen mittels Thermografie
Laserdurchstrahlschweißen transparenter Kunststoffe
Quantifizierung der Werkstoff-Dämpfungseigenschaf-
ten mittels Dorneinschmelzversuch
Laserstrahlmikroschweißen von transparenten
Kunststoffen
VON DER PROJEKTIDEE
ZUM PROTOTYPEN?
CHWEISV STI
EFFEKER EFFIZI
EBIL
SEN?
CHWEISER
DENT O
ER EFFIZI
OTZUM PRO
ER PRON D
VO
YPEN?TTYPEN?
O
EE DTIJEK
ER PRO
TEN?ERA
GUT B
ÜGER F
N DI
TEN?
K ITECHN
EÜG
Kunststoffschweißtechnik
in Perfektion
Plastics Welding
Technology in Perfection
www.wegenerwelding.de
Besuchen Sie uns:
Halle 11, Stand A40
Visit us:
Hall 11, Stand A40
Warmgasschweißgeräte
Extrusionsschweißgeräte
Stumpfschweißmaschinen
Biegemaschinen
Sondermaschinen
Hot Air Welding Tools
Extrusion Welders
Butt Welding Machines
Bending Machines
Custom Designed Machines
joining_plastics210x150_Layout 1 25.01.2019 13:59 Seite 1
1⁄2019
Themen der Fachbeiträge
� Fügetechnologien in der Luftfahrt
� Untersuchungen zur Dimensionierung der
statischen Auszugsfestigkeit des Schraub-
blindniets
� Hybridfügen von Metall und Kunststoff
� Langzeitbelastung von Ultraschallschweißver-
bindungen – Einfl uss zyklischer Lasten
Topics of the Peer-reviewed Papers
� Joining technologies in aviation
� Investigations into the dimensioning of the
static pull-out strength of the screwed blind
rivet
� Hybrid joining of metal and plastic
� Long-term exposure of ultrasonic welded
joints - Infl uence of cyclic loads
www.fuegen-von-kunststoffen.deww.joining-plastics.infoJOINING PLASTICS
FÜGEN VON KUNSTSTOFFENSupported by
7499
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HSK Kunststoff Schweisstechnik GmbH
Kunststoff Schweißtechnik
plastic welding technology
E-mail: [email protected]
Internet: www.hsk-kunststoff.deTel.: +49 2224 90175 01
Fax: +49 2224 90175 03
HSK Kunststoff Schweisstechnik GmbH
Zilzkreuz 1D-53604 Bad Honnef
Germany
Anz_210x150_Layout 1 20.04.2015 18:37 Seite 1
2 ⁄2019
Themen der Fachbeiträge
Evaluierung von Strahloszillationsmustern beim
quasi-simultanen Laserdurchstrahlschweißen
Reaktive Multischichtsysteme zum Fügen von
Kunststoff- und Hybridverbindungen
Inline-Überwachung der Klebstoffaushärtung
mit berührungslosem Ultraschall
Laserdurchstrahlschweißen transparenter
Kunststoffe – Teil 2
Topics of the Peer-reviewed Papers
Evaluation of beam oscillation patterns during
quasi-simultaneous laser transmission welding
Reactive multilayer systems for plastic and
hybrid joints
Inline monitoring of the adhesive curing with
contactless ultrasound
Laser transmission welding of transparent
plastics – Part 2
www.fuegen-von-kunststoffen.de www.joining-plastics.info
JOINING PLASTICS
FÜGEN VON KUNSTSTOFFEN
Supported by
7499
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