Laser transmission welding of PMMA using IR semiconductor laser complemented by the Taguchi method and grey relational analysis Kadhim A. Hubeatir Laser and Optoelectronics Engineering Department, University of Technology, Baghdad, Iraq article info Article history: Received 8 July 2019 Received in revised form 8 September 2019 Accepted 29 September 2019 Available online xxxx Keywords: Semiconductor laser Laser transmission welding Polymer Taguchi method Grey relational analysis abstract Laser transmission welding involves localized heating and non-contact techniques at the interface of two polymer pieces to be joined. The welding quality is very sensitive to speed welding, thickness and weld- ing line width and depth. This work presents the laser transmission welding of Poly(Methyl Meta acrylate) PMMA polymer transparent and oblique slabs. A semiconductor laser with 808 nm wavelength, 2 W output power and a 2 mm beam diameter was used. Three different transparent slabs with dimen- sions 40 Â 60 mm and thickness (2.6, 3.7, 4.3 mm) were fixed tightly onto oblique slab (dark color). Three different selected speeds (44, 113, 150 mm/min) of the welding process were applied to the prepared samples. Results indicate the welding line width and depth were inversely proportional to the welding speed while the transparent slab thickness have little effect. Nine experiments were performed for the three different thickness at different speeds. Taguchi method and grey relational analysis were used to determine the optimum values for welding speed, width, depth and thickness during these nine exper- iments. The results exhibit good agreement with those of the Taguchi method and grey relational analysis. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Materials Engineering & Science. 1. Introduction Laser transmission welding (LTW) technology has attracted considerable interest in recent years. It is typically used to join similar thermoplastic materials at high speed and precision with- out the use of adhesives. A moving laser source penetrates the upper transparent material and then absorbed by the oblique sur- face of the lower material. Therefore, the entire or a considerable proportion of the laser beam’s thermal energy is absorbed by the opaque material thereby producing the required heat at the inter- face between the two materials [1]. Bappa Acherjee, Arunanshu S. Kumar [2] studied (LTW) of polycarbonate to ABS, the effect of laser power, welding speed, stand off distance and clamp pressure on weld strength and track width is investigated. The weld strength is significantly depend on these above factors. Xiao Wang et al. [3] studied laser transmission spot welding with poly(methyl methacrylate) (PMMA) by using the pulsed Nd: YAG laser. The influence of the peak voltage, defocusing distance and welding type, on welding quality have been investigated. L. S. Mayboudi et al. [4] examined the thermal modeling aspects of LTW of thermoplastics for joining plastic parts. Lab joint geometry was modelled for semi crystalline (polyamide-PA6) and amor- phous (polycarbonate PC) materials. Experimental and theoretical studies have been conducted to estimate the optical properties of materials, such as the absorption coefficient of laser, the absorbing part and light scattering by the laser transmitting part. Annamaria Visco and Cristina Scolaro [5] used a diode laser source with awavelength of 970 nm (Lambda Scientific Systems) and small amounts of carbon nano particles. A morphological study of the welded area was performed. The laser energy produced a thermal effect on the heat-affected zone. Thereby smoothing the surface at a depth of approximately 1.5 mm. Moreover, surface roughness decreased and the permeability of the joint to biological fluids was enhanced. Adhish Majumdar et al. [6] presented thermal analysis of the LTW process for thermoplastics using the finite element method in addition to heat transfer equations, An original approach was used to calculate phase transformation phenomena, such as melt- ing, evaporation or decompostion and solidification, of a polymer. MD shakibul, Mohd. Anecs Siddiqui [7] investigated welding pro- cesses, such as hot gas welding, fraction welding and hot plate https://doi.org/10.1016/j.matpr.2019.09.167 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Materials Engineering & Science. E-mail address: 140034@uotechnology.edu.iq Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: K. A. Hubeatir, Laser transmission welding of PMMA using IR semiconductor laser complemented by the Taguchi method and grey relational analysis, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.167