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.

The cooling rate is one of the main tools available to the process engineer by means of which it is possible to influence the crystallisation process. Imposing a desired microstructure on a casting as early as in the casting solidification phase widens significantly the scope of technological options at disposal in the process of aluminium-silicon alloy parts design and application. By changing the cooling rate it is possible to influence the course of the crystallisation process and thus also the material properties of individual microstructure components. In the study reported in this paper it has been found that the increase of cooling rate within the range of solidification temperatures of a complex aluminium-silicon alloy resulted in a decrease of values of the instrumented indentation hardness (H IT ) and the instrumented indentation elastic modulus (E IT ) characterising the intermetallic phase occurring in the form of polygons, rich in aluminium, iron, silicon, manganese, and chromium, containing also copper, nickel, and vanadium. Increased cooling rate resulted in supersaturation of the matrix with alloying elements.

The paper presents results of metallographic examination of faults occurring in the course of founding thin-walled cast-iron castings in furan resin sand molds. A non-conformance of the scab type was Observed on surface of the casting as well as sand buckles and cold shots. Studied the chemical composition by means of a scanning electron microscope in a region of casting defects: microanalysis point and microanalysis surface. Around the observed defects discloses high concentration of oxides of iron, manganese and silicon. A computer simulation of the casting process has been carried out with the objective to establish the cause of occurrence of cold shots on casting surface. The simulation was carried out with the use of NovaFlow & Solid program. We analyzed the flowing metal in the mold cavity. The main reason for the occurrence of casting defects on the surface of the casting was gating system, which caused turbulent flow of metal with a distinctive splash stream of liquid alloy.

The mechanical properties of composites based on polyamide 6 (PA6), polyamide 66 (PA66) and polyphthalamide (PPA) reinforced with fiberglass were tested. Flexural strength, Shore and Rockwell hardness and also notched and without a notch impact strength according to Charpy were determined. The best results of the strength tests were observed for the PA66 composite with 35 wt % fiberglass. The analyzed composite materials can be successfully used in the production of substitutes for machine elements made of metal.

Rapid prototyping is the technology of automatic freeform fabrication of physical objects from virtual CAD (computer aided design) models. For medical objects the models may be created using data from CT, MR or rotational angiography. We descriobe the case of a 83-year-old woman with essential bilateral hearing impairment as the effect of chronic otitis media. An individually fitted hearing aid was produced for the patient using stereolithography technology and vacuum casting based on data obtained during ear CT. Rapid prototyping may help in manufacturing individually adjusted biomedical prostheses, reducing the time of device production and improving its fitting.