Effect of thermal treatments on the laser sinterability of cryogenically milled polybutene-1

Abstract

As the material market for laser sintering (LS) is currently dominated by polyamides, this research aims to widen the material pallet by investigating the feasibility of PB-1 for the application. Due to the polymorphism of PB-1, different thermal treatments were applied to obtain powder with a different crystalline structure. Lab tests on DSC, WAXS, rheology and TMA showed problems with the thermal window for the untreated, twinned hexagonal powder, mainly originating from the powder stickiness at temperatures in the melting onset, but the thermal treatments were able to improve the thermal window, by sharpening and shifting this onset to higher temperatures. Small-scale sintering tests validated the applicability of the treated powders via the creation of sintered multilayers. Higher bed temperatures were possible due to the thermal treatments, thus confirming the lab experiments. High shrinkage was, however, seen post cool down, as the crystal structure transforms from the tetragonal to the twinned hexagonal structure in a timespan of several days.

Influence of selective laser melting process parameters on texture evolution in pure copper

“…The particle size distribution was obtained using a Beckman Coulter LS 13 320 particle size analyzer in dry mode and the oxygen content was measured by the inert gas fusion technique. Flowability was measured by the dynamic angle of repose (AoR) technique (Van den Eynde et al, 2018).…”

Influence of Carbon Nanoparticle Addition (and Impurities) on Selective Laser Melting of Pure Copper

“…This expression assumes zero transmission and it is a reliable assumption in the case of opaque materials, such as copper powder. The flowability was evaluated while using the dynamic angle of repose (AoR) technique [28]. In this technique, a transparent cylindrical drum with a diameter and length of 55 mm and 15 mm, respectively, is half-filled with the powder.…”

Modification of Electrical and Mechanical Properties of Selective Laser‐Melted CuCr0.3 Alloy Using Carbon Nanoparticles

“…All the optical absorption measurements were carried for wavelengths in the range of 400–1400 nm, with an interval of 2 nm and in the reflectance mode. The optical absorption (%) was calculated using the formula “optical absorption (%) = 100 – reflection (%).” Powder flowability was measured using a standard Hall flow test according to the ASTM B213 norm and using a dynamic angle of repose (AoR) test . A powder with an average angle below 40° is defined as good flowable, in the dynamic AoR technique.…”