Every year, the EU emits 13.4 Mt of CO₂ solely from plastic production, with 99% of all plastics being produced from fossil fuel sources, while those that are produced from renewable sources use food products as feedstocks. In 2019, 29 Mt of plastic waste was collected in Europe. It is estimated that 32% was recycled, 43% was incinerated and 25% was sent to landfill. It has been estimated that life-sciences (biology, medicine, etc.) alone create plastic waste of approximately 5.5 Mt/yr, the majority being disposed of by incineration. The vast majority of this plastic waste is made from fossil fuel sources, though there is a growing interest in the possible use of bioplastics as a viable alternative for single-use lab consumables, such as petri dishes, pipette tips, etc. However, to-date only limited bioplastic replacement examples exist. In this review, common polymers used for labware are discussed, along with examining the possibility of replacing these materials with bioplastics, specifically polylactic acid (PLA). The material properties of PLA are described, along with possible functional improvements dure to additives. Finally, the standards and benchmarks needed for assessing bioplastics produced for labware components are reviewed.

One of the established limitations of metal additive manufacturing (AM) methods, such as selective laser melting (SLM), is the resulting rough surface finish. Laser polishing is one method that can be used to achieve an improved surface finish on AM printed parts. This study is focused on the laser surface polishing of AM parts using CO₂ laser beam irradiation. Despite the fact that several researchers have investigated the traditional abrasive polishing method, there is still a lack of information reporting on the laser surface polishing of metal parts. In this study, AM 316L stainless steel cylindrical samples were polished using CO₂ laser beam irradiation in continuous wave (CW) working mode. Two design of experiment models were developed for the optimization of the input processing parameters by statistical analysis of their effect on the resulting roughness. The processing parameters investigated were the laser beam power, the rotational speed of the sample, the number of laser scan passes, the laser beam focal position, and the percentage overlap of the laser tracks between consecutive passes. The characterization of the measured roughness and the modified layer microstructure was carried out using 3D optical and scanning electron microscopy (SEM). A maximum reduction of the roughness from 10.4 to 2.7 µm was achieved and no significant change in the microstructure phase type and micro-hardness was observed.

Laser-Powder Bed Fusion (L-PBF) of metallic parts is a highly multivariate process. An understanding of powder feedstock properties is critical to ensure part quality. In this paper, a detailed examination of two commercial stainless steel 316L powders produced using the gas atomization process is presented. In particular, the effects of the powder properties (particle size and shape) on the powder rheology were examined. The results presented suggest that the powder properties strongly influence the powder rheology and are important factors in the selection of suitable powder for use in an additive manufacturing (AM) process. Both of the powders exhibited a strong correlation between the particle size and shape parameters and the powder rheology. Optical microscope images of melt pools of parts printed using the powders in an L-PBF machine are presented, which demonstrated further the significance of the powder morphology parameters on resulting part microstructures.

The roughness of a material’s surface is a significant factor affecting the absorption of energy when scanned with laser beam radiation. It is a robust variable affecting the entire laser process cost and the appropriate levels for the laser processing parameters, such as the power applied. It is thus an important factor for many processes, such as laser cutting, welding, roughening, and polishing. As such, an examination of the effect of roughness on laser absorption is desirable to determine how input parameters, such as power, must be adjusted when working with different roughness and the potential power savings of roughening samples, or eliminating polishing or finishing steps, before laser processing. In this study, a comparison of the effect of the surface roughness of flat 316L stainless steel and aluminum samples on the thermal energy absorbed in laser processing was investigated. The aim was to characterize the effect and identify the potential energy savings. Samples were processed as received and either polished or roughened, such that there were five different roughness levels for each material. Individual carbon dioxide laser shots were applied with large unprocessed gaps in order to allow clear investigation of the crater depth dimensions. The width, length, and depth of the craters were measured by both scanning electron microscope and three-dimensional microscope, with larger dimensions indicating a greater absorption of the laser energy. The expected outcome of the study was confirmed, finding a noticeable improvement in the absorbed energy on the rougher surfaces for both materials, with a saving of ∼62 % in the laser power applied when the aluminum surface roughness increased from 2.4 μm to 7.03 μm.