The multi-beam selective laser forming system is a new type of powder bed laser forming equipment that is different from single-laser selective laser melting (SLM) printers. It is a new generation for a metal powder material moulding process that has high efficiency, large size and batch manufacturing. It is a new development of a powder bed laser forming process trend. In this paper, the microstructure and tensile properties of both the multi-laser-formed AlSi10Mg isolated and overlap areas are studied to ensure that the parts can achieve perfect seamless splicing and to identify whether the parts in different regions have the same performance. It was discovered that as the number of scans increases, the depth and width of the melt pool and microscopic grain structure in the overlap zone increase. The preferential crystallite growth orientation reaches the (200) plane. A small amount of smooth surface appeared at the fracture of the overlap area of the two scans, the dimples were reduced and the structure became larger, resulting in a decrease in tensile properties.

Topology optimisation is an effective approach to design extreme lightweight components. However, most of the resulted optimum lightweight components usually have complex structures which cannot be produced successfully by traditional manufacturing processes. Selective laser melting is one of the additive manufacturing processes. It shows powerful capacity in the manufacturing of metal components with complex structures. Therefore, the combination of topology optimisation and selective laser melting shows a promising prospect for metal components. However, support structures were usually introduced during the selective laser melting manufacturing process, which resulted to some disadvantages, for example, the support structures are generally difficult to remove from the original components because it is difficult to clamping and machining. Therefore, a design method was proposed in this study, named lightweight and support-free design method, the detailed design process and advantages were presented. In the design process, topology optimisation was applied to realise lightweight design, and support-free design process was developed to meet the support-free requirement. Finally, as a case, a cross-beam component was designed using the proposed method, and the final model was produced successfully using selective laser melting process. The case study result verified that the proposed design method is effective to design lightweight and support-free industrial metal components for SLM process.

CuCrZr alloy has the advantages of good electrical conductivity, thermal conductivity, high hardness, crack resistance and high softening temperature. It is extensively used in important fields such as rail transit, aerospace, thermonuclear fusion and electronic information. Due to its high melting point, reflectivity, thermal conductivity, etc., it is more difficult to manufacture by selective laser melting (SLM). In this work, the effect of SLM process parameters on the characteristics of CuCrZr samples, such as relative density, hardness and tensile properties, has been investigated using orthogonal experiment method. The experimental results show that laser power is the main factor affecting the properties of the alloy. The tensile strength of the alloy increases with an increase in laser power; it first increases and then decreases with an increase in scanning speed. The optimal combination of process parameters in this paper is as follows: laser power is 240 W, scanning speed is 750 mm/s and scanning spacing is 0.07 mm. The relative density, ultimate tensile strength and hardness of the alloy fabricated by best SLM process parameters was 98.79%, 347 MPa, 133.9 HV, respectively.

Multi-laser beam selective laser melting (SLM) technology based on a powder bed has been used to manufacture AlSi10Mg samples. The AlSi10Mg alloy was used as research material to systematically study the performance consistency of both the laser overlap areas and the isolated areas of the multi-laser beam SLM manufactured parts. The microstructures and mechanical properties of all isolated and overlap processing areas were compared under optimized process parameters. It was discovered that there is a raised platform at the junction of the overlap areas and the isolated areas of the multi-laser SLM samples. The roughness is significantly reduced after two scans. However, the surface roughness of the samples is highest after four scans. As the number of laser scans increases, the relative density of the overlap areas of the samples improves, and there is no significant change in hardness. The tensile properties of the tensile samples are poor when the overlap area width is 0, 0.1, or 0.2 mm. When the widths of the overlap areas are equal to or greater than 0.3 mm, there is no significant difference in the tensile strength between the overlap and the isolated areas.

In this paper, the compression behavior of a triply minimal periodic surface (Shwartz Diamond) fabricated by selective laser melting (SLM) under different loading rates was studied. A quasi-static strain rate of 2.22 × 10⁻³/s was tested using a universal testing machine, and a strain rate of 650/s was tested by Hopkinson pressure bar (SHPB). The results showed that the yield stress of all structures increased under dynamic load, and the DIF of sheet structure was higher than that of the skeleton structure, among which the DIF of GSHD was the largest and most sensitive to strain rate. However, the normalized SEA of USHD was the highest.