International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This contribution deals with the study of cut surface after the abrasive water jet application on the material Maraging Steel MS-1, prepared in the form of 3D printing method Direct Metal Laser Sintering. The aim of the study is to point out the morphology of the cut plane under the use of various technological parameters, like feed rate of machining and abrasive mass flow at the constant cut pressure. For the track morphology monitoring after the abrasive water jet application, scanning electron microscope SEM MIRA 3, f. Tescan, was used. For the identification of observed particles stabbed in the cut track, chemical composition EDX analysis was used.

Today, 3D printing is available not only for industrial, semi-professional use, but also for hobbies and schools. Therefore, students TUL make full use of 3D printing within the subject Project Management. One of the topics they address is use of 3D printing for a textile product. They are looking for an answer to the question: How to 3d printing technology use for made a textile product?

The most important areas of the industry, need products with short development stages. Additive manufacturing (AM) techniques, as Fused Deposition Modelling (FDM), are an integrated solution to the overall conception and product development cycles; the same competition is based on the development of new products with technological features, design and functional solutions in the shortest time. In this paper are discussed different process parameters for fused deposition modelling that affects the parts quality by using a low-cost 3D printer machine in order to produce an industrial product. The process parameters taken into the analysis, resulted effective in improving final parts quality.

The preparation of XRF tablets with small amounts of samples produced from various synthesis is a challenging operation. Zeolites and other types of samples with minimal volumes are frequently provided for analysis by X-ray fluorescence spectroscopy. Here we present three types of holders made of PLA (polylactic acid) using commercially available 3D printing technology. The employed material is a bioactive thermoplastic aliphatic polyester extracted from renewable resources and is biodegradable. The holders have reduced diameters of the measured area and can accommodate powders, sheets or solid state samples. The holders are basically three-dimensional plastic models that can be designed and printed based on the provided sample. They are low cost and can be easily applied in practice. The design of the first type of holders is targeting powder samples, allowing the reduction of the required amount from 5-10 g per sample to 1 g. The second type of holders aimed the XRF analyses of textile like materials while the third type of design aimed metal alloys. Examples of the use of the holders are the analyses of coins (here 2 leva is shown) and textile samples containing different metals (e.g. zinc).

With the rise of additive manufacturing (AM) technologies, a numerous limitations in conventional manufacturing have been circumvented. Additive manufacturing uses layer-by-layer fabrication of three-dimensional physical models directly from a computeraided design (CAD) model. The CAD design is transformed into horizontal cross-section layers that are stacked together in physical space until the physical model is completed. This process can be used to directly manufacture tools for injection molding or for an y other technology that requires a specific cavity shape to produce a part. This is referred to as Rapid Tooling (RT) and one of the up and coming
AM technologies is the resin based stereolithography (SLA).
An increasing number of companies are starting to develop desktop machines that utilize this technology and their low cost an d high speed changes the design workflow. As a printing technology, SLA creates parts with a smooth surface finish which is ideal for applications such as investment casting for developing jewelry or rapid tooling for injection molding.
The development of rapid tools using SLA usually requires more rigid materials which can withstand higher temperatures and stresses and part models that need to have more accurate dimensions in order for a precise part to be produced from that specific tool. Even though models created by SLA have more isotropic characteristics compared to other 3D printing technologies, there are still some variations linked to the process parameters. This paper covers how orientation of the model on the build plate impacts the pa rt accuracy and the tensile strength of the models. The effects of different post-processing procedures after SLA printing are also taken into consideration, since most resins need to be UV cured after 3D printing in order to achieve maximum mechanical strength.
This paper gives designers and engineers better understanding on the final properties of the models and the tolerances that have to be taken into consideration when designing parts intended to be manufactured via SLA 3D printing.

In the paper consider materials for the rapid prototyping (RP) of experimental samples of filtering materials with an orthotropic structure based on woven nets (FMWN) assembled together with test-form and with using of 3D printing. RP made it possible to reduce the labor intensity of the process, primarily by eliminating the operation of sealing samples when using a traditional test form, as well as making the test form and the samples themselves. The data obtained allowed us to conclude that the use of 3D-printing is promising in further work for the manufacture of test form for studying the properties of filtering materials.

Additional manufacturing (AM), commonly known as 3D printing, exists for 40 years, still evolving and improving. AM has gained great popularity in modern industries due to many advantages concerning conventional manufacturing technologies. Consequently, AM is one of nine pillars of the currently dominating industry trend – Industry 4.0. Initially, AM was mostly used for making models. Now, objects made by AM technologies, often are physical parts ready to be used as final products or to be installed as parts of assemblies in more complex systems. Because of that, in more applications, the mechanical properties of these parts have to be known for the purpose to determine load carrying capacity essential for their functionality. Mechanical properties are being tested using appropriate methods, specimens, and equipment. In order to obtain comparable and evaluable test results, the test procedures and means should be s tandardized. Therefore, there was a need to develop standards for testing materials used for AM. International standardization in the field of AM started 10 years ago. The international body for standardization ISO developed and published a certain number of standards, but this is just beginning. This paper discusses aspects of AM standardization in the field of testing the mechanical properties of materials for 3D printing using fused deposition modelling (FDM). As an illustration of the standard application, specimens were prepared for testing the tensile properties of plastic materials widely used in AM: PLA, PETG and ABS+.

In the presented paper is examined the need for digitalization of cultural and historical sites. Approaches for 3D digitalization by using 3D scanners and photogrammetry are presented. A 3D printing of digitalized objects is accomplished. The photogrammetry method is examined and used as a possible solution for the digitalization and creation of 3D models. The models can be explored by visually impaired people. A monument from the Cultural and Historical site of Bulgaria is 3D digitalized and 3D printed by using a drone, photogrammetry software, and 3D printer.

A personalized approach to printing individual shoes is possible due to the availability of laser scanning of the feet and professional interpretation of the results. Based on preliminary diagnostics of the condition of the musculoskeletal system in areas of high pressure in the feet, it is possible to identify problems associated with pain in the joints of the lower extremities and lumbosacral, abnormalities and asymmetries of their structure. It is also possible to timely relieve ankle, knee, femoral joints, lumbosacral spine, correct posture and gait, reduce joint pain, prevent surgery on joints of the lower extremities and lumbosacral spine, monitor the dynamics of changes in the rehabilitation period.
The task of effective prevention and early diagnosis of problems of the musculoskeletal system can be solved with the targeted popularization of individual shoes and orthopedic insoles among the population, as well as its accessibility thanks to additive technologies, databases of parametric digital models, an established production and technological cycle and a flexible client-oriented service , including protocols for remote and virtual interaction between production and the end user.
However, shoes printed on a 3-D printer, so far, are not attractive to consumers or manufacturers. Mass production of shoes is still much faster and cheaper, although initially it was assumed that the introduction of additive technologies will significantly reduce the cost and time costs, but so far this has not happened for several reasons. In our country, there is a shortage of specialists in digital technologies, 3Dmodeling and printing. In addition, as elsewhere in the world, equipment for fast 3D printing has a very high cost and only giants such as Adidas or Nike can create real production of printed products. However, it is a matter of time. The area of additive technologies is attracting more and more medium and small firms, individual designers, because 3D printing allows you to achieve unexpected and revolutionary results, as well as provide customized solutions at an affordable price.

This paper covers the advanced Additive Manufacturing (AM) techniques used to fabricate prostethic and orthotic devices. It reviews the available literature and summarizes the advances in medicine, computing and engineering that have led to the development of currently available prostheses. Some of the open-source bionic hands and other available prosthesis are shown, as well as the technologies and materials which are used to manufacture the parts. Since prototyping, combined with the possibility for easy maintenance and repair, is very attractive for prosthesis design, as a conclusion we summarize and discuss some of the key areas that could lead to improvements in bionic limb functionality and use.

Two tasks are enumerated: a task of hardening spheres with a radius of 50 nm and a task of crystallization – the underlying kinetic equation of formation of new phases. These tasks are rational bridges for multi-scale approach.
There is an opportunity to create additive production with traditional machines and technologies in the field of anti-pressure casting

Technological developments are fast and at industry level we have fourth industrial revolution going on. More and more new
technologies are being applied to production to make it more efficient and more competitive. In order for new technologies to be better implemented and for the end user to be able to apply them to their industry, it is necessary for educational institutions to accompany the rapid development of technology and apply these new technologies in curricula.