To read this content please select one of the options below:

Reflectance and transmittance of TrueFormTM powder and its composites to CO2 laser

K.M. Fan (Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China)
K.W. Wong (Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China)
W.L. Cheung (Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China)
I. Gibson (Department of Mechanical Engineering, National University of Singapore, Singapore)

Rapid Prototyping Journal

ISSN: 1355-2546

Article publication date: 5 June 2007

973

Abstract

Purpose

The purpose of this paper is to report on a study of the effect of glass microsphere (GMS) and potassium bromide (KBr) powder as an additive on the reflectance and transmittance of TrueFormTM acrylic‐styrene co‐polymer (TF) powder to CO2 laser during selective laser sintering (SLS).

Design/methodology/approach

GMSs and KBr powder were chosen because glass is opaque to CO2 laser while KBr is transparent. The GMSs were treated with silane coupling agent and hydrofluoric acid to study the surface effect on the optical properties of TF/GMS blends. KBr powder was blend with TF powder in an attempt to modify the penetration depth of the laser in the powder bed. An integrating sphere was used to measure the reflectance of the powder bed. In the measurement of transmittance, a power meter was placed below the powder layer, which was supported by a KCl disc, to register the transmitted laser energy through the powder layer.

Findings

For the TF/GMS blends, smaller GMSs gave a higher reflectance while the surface treatments had little effect. The transmittance of both the polymer and the blends were very low. Although bulk KBr is highly transparent to CO2 laser, adding 30 vol% of KBr powder to TF hardly increased the transmittance of the powder bed.

Research limitations/implications

Experiments were carried out on a modified laser engraving machine rather than a commercial SLS machine. The laser energy density used was lower than that for normal SLS processes and no significant changes of physical condition of the powder bed were inflicted. The results only indicate the optical properties in the initial state.

Practical implications

The effects of transparent and non‐transparent fillers on the optical properties of the powder bed are presented.

Originality/value

This work furthers the understanding of heat absorption behavior of the powder bed during SLS.

Keywords

Citation

Fan, K.M., Wong, K.W., Cheung, W.L. and Gibson, I. (2007), "Reflectance and transmittance of TrueFormTM powder and its composites to CO2 laser", Rapid Prototyping Journal, Vol. 13 No. 3, pp. 175-181. https://doi.org/10.1108/13552540710750924

Publisher

:

Emerald Group Publishing Limited

Copyright © 2007, Emerald Group Publishing Limited

Related articles