The paper presents the process of modeling a rocket engine nozzle and the manufacturing method of a nozzle intended for use in micro-rocket propulsion systems. The proposed design–technological solution enables the fabrication of a rocket engine component with reduced mass through the application of a structure that allows optimization of the cooling process during flight. Designs incorporating conformal cooling channels make it possible to reduce weight while maintaining high performance, equal to or at least comparable with that of conventionally used designs manufactured using traditional subtractive methods. The presented solution is based on additive manufacturing technologies.

The first part of the research presented in this article, related to the geometric accuracy of models made using four specific additive manufacturing methods: Material Extrusion Modeling (MEM), es on the accuracy of rectangular and cylindrical models. For this purpose, research models were developed containing cylindrical and rectangular solids and holes in the dimensional range 0.1-10 mm. Based on the results, it was found that DMLS models are characterized by the highest geometric accuracy.

This article presents a strength analysis of selected polymer materials ABS (acrylonitrile butadiene styrene), PLA (polylactic acid), HABS (hard acrylonitrile butadiene styrene), HIPS (high-impact polystyrene), PC/ABS (acrylonitrile butadiene styrene with polycarbonate), and S&S (strong and soft)) used in the FFF method based on a static tensile test. Standardized type 1A specimens with varying filling densities of the internal grid structure were tested, specifically at densities of 13%, 15%, 20%, 65%, 80%, and fully filled. Additionally, the fractures of the samples following the strength tests were examined and described.

The article presents the course and results of research aimed at assessing the strength and practical usability of a furniture hinge additively manufactured from thermoplastic material. The research activities included: development of design assumptions, adoption of target geometry, creation of a 3D-CAD model, preliminary strength analysis in the FEM environment, prototype manufacturing using FFF method with thermoplastic material (pet-g), and conducting tests under conditions similar to real ones. The hinge geometry was based on typical market-available design solutions, while considering the specifics of the adopted manufacturing method. Strength analysis via FEM was conducted on the 3D-CAD model, allowing estimation of stress values and determination of the suitability of the developed geometry for testing on a real model. Subsequently, research models were produced using FFF technology with various infill patterns: linear 30%, hexagonal 30%, linear 60%, hexagonal 60%, and solid 100%. Bench tests were conducted to determine the maximum load-bearing capacity of the hinge under perpendicular loading to the axis and to assess hinge wear under conditions simulating real-life door usage. The results revealed that the hinge with solid infill safely carried a load of 160 kg without damage, while the hinge with hexagonal 30% infill exhibited the lowest load-bearing capacity, failing at 85 kg. To determine the hinge's durability, the clearance at two reference points on the doors was measured.

Broadly, understood additive manufacturing techniques expand the spectrum of production of machine parts that are used in various types of devices. However, the requirements to ensure dimensional and shape accuracy require the determination of appropriate material allowances or clearances to enable correct assembly. For the above reasons, the study presents an analysis of the impact of the assumed geometry modifications on the possibility of assembling a splined connection manufactured using selected AM techniques. The work focused on the analysis of changes in geometry resulting from the technology used. Using the Atos II Triple Scan optical measurement system and Gom Inspect software, the possibility of installation was determined for four variants of the splined shaft connection geometry, resulting from the technologies used.

Durability of polymer (PCTG, ABS, PLA) chain gears with a modular chain obtained by 3D printing (FFF - Fused Filament Fabrication) was tested under static and dynamic conditions. An analysis was performed using finite element modeling (FEM). The PLA gear showed the highest tensile strength, and the PCTG gear the lowest. However, in dynamic conditions (rotational speed 750 min-1), the ABS gear was characterized by the smallest deformation and the longest operating time. Chain links were damaged at the point of connection during both static and dynamic tensile tests. Probably the surface of the hole where the chain links were joined was not smooth enough, which could lead to their damage.

Purpose Manufacturing of products loaded with torque in an incremental process should take into account the strength in relation to the internal structure of the details. Incremental processes allow for obtaining various internal structures, both in the production process itself and as a result of designing a three-dimensional computer-aided design model with programmable strength. Finite element analysis (FEA) is often used in the modeling process, especially in the area of topological optimization. There is a lack of data for numerical simulation processes, especially for the design of products loaded with torque and manufactured additive manufacturing (AM). The purpose of this study is to present the influence of the internal structure of samples produced in the material extrusion (MEX) technology on the tested parameters in the process of unidirectional torsion and to present the practical application of the obtained results on the example of a spline connection. Design/methodology/approach The work involved a process of unidirectional torsion of samples with different internal structures, produced in the MEX technology. The obtained results allowed for the FEA of the spline connection, which was compared with the test of unidirectional torsion of the connection. Findings The performance of the unidirectional torsion test and the obtained results allowed us to determine the influence of the internal structure and its density on the achieved values of the tested parameters of the analyzed prototype materials. The performed FEA of the spline connection reflects the deformation of the produced connection in the unidirectional torsion test. Originality/value There are no standards for the torsional strength of elements manufactured from polymeric materials using MEX methods, which is why the industry often does not use these methods due to the need to spend time on research, which is associated with high costs. In addition, the industry is vary of unknown solutions and limits their use. Therefore, it is important to determine, among others, the strength parameters of components manufactured using incremental methods, including MEX, so that they can be widely used because of their great potential and thus gain trust among the recipient market. In addition, taking into account the different densities of the applied filling structure of the samples made of six prototype materials commonly available from manufacturers allowed us to determine its effect on the torsional strength. The presented work can be the basis for constructors dealing with the design of elements manufactured in the MEX technology in terms of torsional strength. The obtained results also complement the existing material base in the FEA software and perform the strength analysis before the actual details are made to verify the existing irregularities that affect the strength of the details. The analysis of unidirectional torsion made it possible to supplement the material cards, which often refer to unprocessed material, e.g. in MEX processes.

The paper presents an analysis of selected design solutions for spur gears with reduced weight, in which the results obtained are compared to a solid gear without modifications. The reduction of the weight of the gears is of particular importance, among others in the automotive and aviation industries, where it reduces energy consumption, and thus CO2 emissions. It is also important to remember to maintain the required strength parameters when reducing the mass of the gear. This article focuses on the analysis of deformation and stress due to a given load on the considered weight-reduced gears. The values of the obtained static analysis results of the reduced-weight gears were also compared to the base gear.

The article presents the place of 3D printing in the manufacturing and operational process. It analyzes selected incremental technologies in the product life cycle. It describes selected processes for testing the properties of materials used in 3D printing, including accelerated aging tests and simulation of operating conditions. Areas of application of 3D printing were defined, starting from design and prototype development through manufacturing of technological tools and finally finished products. Design criteria of additivelymanufactured elements in relation to the exploitation process are discussed. A methodology for the development of 3D-CAD models of manufactured elements, software processing of data and data storage format for manufacturing products and spare parts is presented. The assumptions of repair procedures based on the production of spare parts by means of 3D printing in relation to data circulation compatible with the idea of Industry 4.0 structure have been adopted.

The geometrical accuracy of injection-molded gears made of PA6, PA66 and PPA filled with glass fiber (30, 35 and 50%) were investigated. Using the AMI software, the injection mold cavity and the injection point distribution were simulated and the orientation of the glass fibers in the product was determined. The low accuracy class of injection-molded gears may indicate the need to optimize the injection process, which will be the subject of further research.

Designing and manufacturing of aeronautic bevel gearboxes is a complicated and time-consuming process. This is due to the high quality requirements to the aviation industry products and the complex kinematic of the machining process. So far, in practice, this process has required a series of research and prototypes testing. The development, has been made in the field of Computer Aided Design systems, allows increasing use in design process and carry out the necessary research in the CAD environment. This approach simplifies and accelerates the aeronautic bevel gearboxes design process. The study presents process of gears solid models generating and carrying out simulate of cooperation bevel gearbox in the CAD environment. Solid models has been prepared by the solid machining simulation, while the performed analyzes are used to determine temporary tooth bearings, summary tooth bearing and motion graphs.

Purpose The purpose of this paper is to present the methodology for manufacturing of aircraft transmission gears using incremental method of rapid prototyping (RP) – direct metal laser sintering (DMLS). The production of prototypes from metallic powders using described system allows the execution of final elements of complex structures with additional economic impacts. Design/methodology/approach The paper describes the use of selective laser sintering method (DMLS) by EOS Company. Whole chain of production of prototype is presented with the addition of geometric accuracy measurements by blue light laser device. Findings Presented in the research analysis of SLS/SLM technologies as rapid manufacturing systems shows that they can be applied in the production of prototypes used in the manufacturing process of gears for propulsion systems in aviation industry. Also, very important is the geometrical accuracy of gear prototypes produced by incremental methods. It determines subsequent treatment steps for aircraft propulsion system gears. Practical Implications The use of RP techniques as an alternative for conventionally used manufacturing method has mainly an economic impact related to the cost of time-consuming process and amount of defected elements appearing in serial production. Originality/value This paper presents possibility to use RP – DMLS system – for propulsion elements of aircraft structure. This research is original because of the complex description of the whole chain of manufacturing process. Additionally, geometrical accuracy measurement methodology by blue light presented with the RP method of manufacturing gives the research a unique characteristic.