Additive manufacturing in recent years has become one of the fastest growing technologies.
The increasing availability of 3D printing devices means that every year more and more
devices of this type are found in the homes of ordinary people. Unfortunately, air pollution is
formed during the process. Their main types include Ultra Fine Particles (UFP) and Volatile
Compounds (VOC). In the event of air flow restriction, these substances can accumulate in
the room and then enter the organisms of people staying there. The article presents the
main substances that have been identified in various studies available in literature. Health
aspects and potential threats related to inhalation of substances contained in dusts and gases
generated during the process are shown, taking into account the division into individual types
of printing materials. The article also presents the differences between the research results
for 3d printing from individual plastics among different authors and describes possible causes
of discrepancies.
The paper presents the properties of plastics under the trade names of PMMA and Midas, and of Formowax, Romocast 305 and Romocast 930 casting waxes. Their effect on the quality of foundry patterns used in the manufacture of ceramic moulds for precision casting is also discussed. From the selected materials for foundry patterns, samples were made for testing using the following methods: (i) 3D printing in the case of plastics, and (ii) conventional method based on tooling in the form of metal moulds (dies) in the case of casting waxes.
The most important physico-mechanical properties of materials for foundry patterns were determined, i.e. linear shrinkage, softening temperature, relative elongation and coefficient of thermal linear expansion. Bending tests were carried out on samples of patterns printed and made in metal moulds, including determination of the surface roughness of patterns.
After the process of melting out patterns from the cavities of ceramic moulds in an autoclave, the degree of their melting out was visually assessed (i.e. the residues from pattern removal were evaluated). The ash content after burning out of foundry patterns was also determined. The conducted tests allowed comparing the important parameters of materials used for foundry patterns and assessing the suitability of selected plastics as a material for foundry patterns used in the manufacture of high-quality precision castings.
Investment casting combined with the additive manufacturing technology enables production of the thin-walled elements, that are geometrically complex, precise and can be easy commercialized. This paper presents design of aluminium alloy honeycombs, which are characterized with light structure, internal parallel oriented channels and suitable stiffness. Based on 3D printed pattern the mould was prepared from standard ceramic material subjected subsequently to appropriate heat treatment. Into created mould cavity with intricate and susceptible structure molten AC 44200 aluminium alloy was poured under low pressure. Properly designed gating system and selected process parameters enabled to limit the shrinkage voids, porosities and misruns. Compression examination performed in two directions showed different mechanisms of cell deformation. Characteristic plateau region of stress-strain curves allowed to determine absorbed energy per unit volume, which was 485 or 402 J/mm3 depending on load direction. Elaborated technology will be applied for the production of honeycomb based elements designated for energy absorption capability.
The anatomy of the human temporal bone is complex and, therefore, poses unique challenges for students. Furthermore, temporal bones are frequently damaged from handling in educational settings due to their inherent fragility. This report details the production of a durable physical replica of the adult human temporal bone, manufactured using 3D printing technology. The physical replica was printed from a highly accurate virtual 3D model generated from CT scans of an isolated temporal bone. Both the virtual and physical 3D models accurately reproduced the surface anatomy of the temporal bone. Therefore, virtual and physical 3D models of the temporal bone can be used for educational purposes in order to supplant the use of damaged or otherwise fragile human temporal bones.
The paper presents an innovative method of creating the layered castings. The innovation relies on application the 3D printing insert obtaining in SLM (selective laser melting) method. This type of scaffold insert made from pure Ti powder, was placed into mould cavity directly before pouring by grey cast iron. In result of used method was obtained grey cast iron casting with surface layer reinforced by titanium carbides. In range of studies were carried out metallographic researches using light microscope and scanning electron microscope, microhardness measurements and abrasive wear resistance. On the basis of obtaining results was stated that there is a possibility of reinforcing surface layer of the grey cast iron casting by using 3D printing scaffold insert in the method of mould cavity preparation. Moreover there was a local increase in hardness and abrasive wear resistance in spite of the precipitation of titanium carbides in surface layer of grey cast iron. While the usable properties of composite surface layer obtained in result of use of the method presented in the paper, strongly depend of dimensions of scaffold insert, mainly parameters Re and Ri.
The densification behavior of H13 tool steel powder by dual speed laser scanning strategy have been characterized for selective laser melting process, one of powder bed fusion based metal 3d printing. Under limited given laser power, the laser re-melting increases the relative density and hardness of H13 tool steel with closing pores. The single melt-pool analysis shows that the pores are located on top area of melt pool when the scanning speed is over 400 mm/s while the low scanning speed of 200 mm/s generates pores beneath the melt pool in the form of keyhole mode with the high energy input from the laser. With the second laser scanning, the pores on top area of melt pools are efficiently closed with proper dual combination of scan speed. However pores located beneath the melt pools could not be removed by second laser scanning. When each layer of 3d printing are re-melted, the relative density and hardness are improved for most dual combination of scanning. Among the scan speed combination, the 600 mm/s by 400 mm/s leads to the highest relative density, 99.94 % with hardness of 53.5 HRC. This densification characterization with H13 tool steel laser re-melting can be efficiently applied for tool steel component manufacturing via metal 3d printing.