Effect of carbon black on temperature field and weld profile during laser transmission welding of polymers: A FEM study

Acherjee, Bappa; Kuar, Arunanshu S.; Mitra, S.; Misra, Dipten

doi:10.1016/j.optlastec.2011.08.008

Cited by 84 publications

(27 citation statements)

References 15 publications

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“…Moreover, in representing the physical mapping of the laser heat input, the heat source is calculated according to the Gaussian distribution and is applied on the powder bed on which the laser is impinged using table type array parameters [27]. Acherjee et al [28] established a volumetric Gaussian heat source model using 3D array (x, y, z) parameters as heat source boundary conditions which is developed from their previous study that using 2D array (x, y) parameters to simulate the surface heat flux source [29]. Consequently, it should be noted that it is very significant to take reasonable heat input profile into consideration, and hence the higher dimension table type array parameters appropriate for the volumetric Gaussian heat source should be added into the finite element model.…”

Section: Finite Element Model Descriptionmentioning

confidence: 99%

A finite element model of thermal evolution in laser micro sintering

Yin

Zhu

Liu

et al. 2015

Int J Adv Manuf Technol

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Laser micro sintering (LMS) is a promising technique for micro-additive manufacturing. During LMS of metallic powder, the material property variation and the heat input energy profile are important to understand physical phenomena involved. This paper presents a finite element temperature distribution profile in LMS of nickel powder on 304 stainless steel substrate. The simulation considered the transition of powder-to-dense sub-model which involves effective thermal conductivity, volumetric enthalpy, and absorptance change; and a moving volumetric Gaussian distribution heat source sub-model. It is found that, for a specified cross section, the mechanism of preheating the nickel powder changes for the heat source from previous laser-irradiated substrate region to molten nickel as the laser beam approaches, while the center of molten pool slice is slightly shifted toward the reverse direction of laser scanning when the laser moves away due to the thermal accumulation effect. Simulated sintered widths showed very good agreement with experimental measurement, and relative prediction errors are below 16 % within the process window.

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Section: Finite Element Model Descriptionmentioning

confidence: 99%

A finite element model of thermal evolution in laser micro sintering

Yin

Zhu

Liu

et al. 2015

Int J Adv Manuf Technol

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“…. The absorption coefficient α was calculated by the Beer's law:

α = - \frac{1}{t} ln \frac{I}{I_{0}}

where I 0 and I are the intensity of the incident and transmitted laser radiation, respectively, and t is the thickness of the film. It is clearly seen that the absorption coefficient increases considerably with increasing the content of CB.…”

Section: Resultsmentioning

confidence: 99%

Effective Laser Sealing Enabled by Glass Thick Films Containing Carbon Black/Carbon Nanotubes

et al. 2013

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An effective way of providing complete sealing of glass using an 810 nm diode laser was investigated for longer lifetime of glass panel‐based devices. Small amounts (<5 wt%) of laser‐absorbing materials such as carbon black (CB) or carbon nanotubes (CNT) were added to a bismuth zinc borate glass paste for instantaneous adhesion between glass substrates without interfacial cracks or severe pores. A higher laser power was required for a lower content of carbon for the laser‐assisted sealing of glass. As optimal compositions, the addition of 1.0 wt% CB or 0.5 wt% CNT led to complete densification of glass with higher optical transmittance. Higher absorption coefficients calculated in the CNT case, e.g., ~536.4 cm−1 for the 0.5 wt% CNT sample compared to ~277.6 cm−1 for the 0.5 wt% CB sample, are believed to be responsible for the effective sealing even with a lower content of CNT.

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“…One of the joining parts must have a high transmittance in the range of the laser wavelength, the other part must exhibit a high absorbance. Before welding, both parts are placed in the desired final position and the joining pressure is applied [7,8]. The transparent joining component transmits the laser beam without any considerable heating.…”

Section: Laser-transmission Weldingmentioning

confidence: 99%

Laser transmission welding of foamed thermoplastic injection moulded parts

Hopmann¹,

Kreimeier²,

Schöngart³

2017

AIP Conference Proceedings

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Abstract. The laser transmission welding is one possibility to join parts, which have been produced in the special injection moulding process structural foam-moulding. Besides reduced weight such parts with reduced density show a reduced cycle time as well as improved size accuracy. Up to now there are no empirical values regarding the laser transmission welding of foamed injection moulded parts. For the use of the laser transmission welding process in a larger scale it is important to acquire knowledge in how far the structure of the foam influences the welding process, the bond strength and the structure of the joint. These knowledges allow an application-specific adjustment of the injection moulding process and the joining process. As part of a current research project the dependence of the foam structure to the injection moulding parameters have been determined using a breathing cavity. That way it is possible to produce parts, which have a defined thickness of the surface layer as well as specified average cell size. Therefore the integral foam parts are analysed via light microscopy. It is shown that the mass flow rate (MFR) has a major influence to the cell structure and the injection time has a significant influence on the thickness of the surface layer. Furthermore the opening speed while mould breathing has an influence on the cell size as well. In addition to these researches the transparent parts have been investigated regarding its transmission properties to show, that the cell structure influences the optical path of the laser beam and therefore the intensity distribution. In further researches the welding suitability of foamed parts is investigated. Therefore the energy input into the material is varied to create process windows and to determine suitable process parameters for the welding process. In addition it is necessary to research the welding pressure, because a high pressure can expel the melt from the joining area and destroy the cell structure.

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Effect of carbon black on temperature field and weld profile during laser transmission welding of polymers: A FEM study

Cited by 84 publications

References 15 publications

A finite element model of thermal evolution in laser micro sintering

A finite element model of thermal evolution in laser micro sintering

Effective Laser Sealing Enabled by Glass Thick Films Containing Carbon Black/Carbon Nanotubes

Laser transmission welding of foamed thermoplastic injection moulded parts

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