(1) Background: With the ever-increasing number of polymer materials and limited data on polymer gear calculations, designers are often required to perform extensive experimental testing in order to establish reliable operational data for specific gear applications. This research investigates the potential of a Polyvinyldene fluoride (PVDF) polymer material in gear applications, considering various loading conditions and different types of gear transmission configurations, including both self-mated mesh and steel/PVDF mesh. (2) Methods: PVDF gear samples were tested on a specially designed test rig that enables active torque control and temperature monitoring in order to obtain the necessary design parameters and failure modes. Each test for certain load conditions was repeated five times, and to fully investigate the potential of PVDF gear samples, comparative testing was performed for Polyoxymethylene (POM) gear. (3) Results: Tribological compatibility, tooth load capacity, and lifespan assessment, along with the types of failure, which, for some configurations, include several types of failures, such as wear and melting, were determined. Temperature monitoring data were used to estimate the coefficient of friction at the tooth contact of analyzed gear pairs, while optical methods were used to determine a wear coefficient. (4) Conclusions: The tribological compatibility of polymer gear pairs needs to be established in order to design a gear pair for a specific application. PVDF gear samples mated with steel gear showed similar lifespan properties compared to POM samples. Temperature monitoring and optical methods serve as a basis for the determination of the design parameters. PVDF is an appropriate material to use in gear applications, considering its comparable properties with POM. The particular significance of this research is reflected in the establishment of the design parameters of PVDF gear, as well as in the analysis of the potential of the PVDF material in gear applications, which gives exceptional significance to the current knowledge on polymer gears, considering that the PVDF material has not previously been analyzed in gear applications.

: Modern technologies are essential parts of Industry 4.0. From automation, robotics, digitalization and additive manufacturing (3D printing) up to 3D scanning and reverse engineering. 3D scanning has a wide range of usage in today product development and design processes. This paper will present several real case studies of 3D scanning in reverse engineering andnew product development and design processes. Paper explores importance of 3D scanning technology, as integral part of Industry 4.0. Seven case studies are explored in more detail. Five of these case studies are realized in Laboratory for Product development and design at University of Sarajevo – Faculty of mechanical engineering as a part of the projects realized in cooperation with several companies from Bosnia and Herzegovina, while two of them are realized in Protodevs company in Sarajevo. Artec Eva 3D scanner and Artec Studio software were used for most of the presented case studies.

The aim of this work is to investigate the impact of geometry on the mechanical stability of characteristic structural solutions of plates for internal bone fixation using the finite element method (FEM). Based on the realistic construction of plates for internal bone fixation, 3D geometric and FEM models were formed, and then structural analysis was carried out in the CAD/CAE system CATIA V5. Five different types of plates for internal bone fixa - tion were tested under two types of loads: axial pressure and torque in the case of application to the femur. During the structural analysis, stresses and displacements were monitored at characteristic points of the structure. The most attention was paid to the relative displacements of the bone model fragments, because the stiffness of the plates for the internal fixation of the bone was determined based on them. At the end of the paper, the results of all analyzed plates are presented, their mutual comparison as well as the conclusion in which, based on everything done, it was stated which plate would be the most favorable solution for a given case of bone fracture.

This study performed a mechanical stability analysis for the impact of axial pressure on an Ultra X external unilateral fixation device applied to a tibia with an open fracture. The real construction of the fixation device was used to create a 3D geometric model using a Finite Element Method (FEM) model, which was made to perform structural analysis in the CATIA V5 (Computer Aided Three-dimensional Interactive Application) CAD/CAE system. Specific stresses and displacements were observed at points of interest using structural analysis. The focus was on the relative displacements of the proximal and distal bone segments in the fracture zone. These displacements were used to calculate the stiffnesses of the bone in the fracture zone and the fixation device itself. The results obtained provide the necessary information regarding the stability of the Ultra X fixation device.

This paper presents a comparative analysis of the biomechanical characteristics of an external fixator with a frame made of two different materials (stainless steel and composite material) during anterior–posterior bending. Before the test itself, two representative configurations of the Sarafix fixator were selected for application on the lower leg and upper extremities under the designations B50 and C50, which are most widely used in orthopedic practice. The examination of the biomechanical characteristics of the external fixator was carried out using the structural analysis of the construction performance of the Sarafix fixator using the finite element method, the results of which were verified through experimental tests. The developed experimental and FEM models study the movement of the fracture crack and enable the determination of the stiffness of structural designs as well as the control of the generated stresses at the characteristic locations of the fixator. The results show that the fixator with a carbon frame has lower stresses at critical points in the construction compared to the fixator with a steel frame, in the amount of up to 49% (at the measuring point MT+) or up to 46% (at the measuring point MT−) for both fixture test configurations. The fixator with a carbon frame has greater displacements at the fracture site compared to the fixator with a steel frame, in the amount of up to 45% (for configuration B50) or up to 31% (for configuration C50). The stiffness of the structure for both test configurations of the fixator is lower in the fixator with a carbon frame compared to the fixator with a steel frame by up to 27%. Based on the findings of this study, we can conclude that a fixator with a steel frame has better biomechanical characteristics compared to a carbon frame.

Analysis of mechanical properties of external unilateral fixation device „ Ultra X “, in the case of torque load, is presented in this paper. Fixation device is applied on lower leg in the case of unstable fracture. Computer aided design (CAD) model and finite element model (FEM) are developed according to the dimensions and material properties of real fixation device. In the next step principal stress and deformation analysis is performed in CATIA V5 software. During numerical analysis values of stresses at critical places are monitored and analyzed. In addi - tion, values of displacements are measured on important places on fixation device and bone fracture. Using values of displacements at the place of bone fracture, stiffness of the fracture is calculated. The same methodology is used to calculate stiffness of the fixation device. Using obtained results, several conclusions about the mechanical properties of the fixation device “Ultra X” are formulated at the end of the paper.

This article explores a possibility to improve mathematical teaching by using 3D printing technology. The question is whether it is possible to use low cost additive manufacturing technology to develop and manufacture real physical prototypes of complex mathematical surfaces and volumes and on that way improve mathematics education. Five mathematical problems were chosen as case studies. Visualization of this problems was done using professor hand drawing, using computer visualization and using development and manufacturing of real physical prototypes. To find out how much better is understanding of these problems, survey with 57 students is carried out. Results showed significant improvements of understanding and better visualization of selected mathematical problems.

In this research, an analysis of the mechanical behaviour for the Orthofix external fixation device under the impact of torque was performed. Research considers application of the Orthofix device on the tibia bone for the case of unstable fracture. 3D (Three Dimensional) model of the Orthofix device was created in the CATIA (Computer Aided Three-Dimensional Interactive Application) software, based on the real device construction. Structural analysis was used to monitor and analyse the stress magnitudes on the specific areas of the fixation device and fracture. With usage of the interfragmentary displacement data for the bone fragments, degrees of stiffness are introduced for the fracture and fixation device. Obtained results are used to specify the mechanical behaviour of the Orthofix fixation device.

The use of digital teaching resources became widespread and very helpful during the COVID‐19 pandemic as an alternative to a traditional course with cadavers. Technologies such as augmented reality (AR), virtual reality (VR), 3D models, video lectures and other online resources enable three‐dimensional visualization of the anatomical structures and allow students to learn more interactively. The aim of this study was to compare students' performance in the traditional anatomical courses in teaching neuroanatomy and technology‐based learning methods such as video lectures, 3D models and 3D printed specimens. Four groups of first‐year students of Veterinary Faculty established for the practical classes during the academic year 2021/2022 took part in this research. The total number of students participating in this research was 72. Each group attended separately the theoretical lecture with a demonstration based on a different technique; the control group used formalized specimens, while the three experimental groups used video lectures, 3D models and 3D printed specimens, respectively. Subsequently, all groups completed the same questionnaire testing their short‐term memory of the neuroanatomical structures. After four weeks students were tested for their long‐term memory of the neuroanatomy lecture with the follow‐up test containing an identical list of questions. The test scores using video lectures and 3D printed models were significantly higher compared with the group that learned in the traditional way. This study suggests that alternative approaches such as technology‐based digital methods can facilitate memorization of anatomical terms and structures in a more interactive and sensory engaging way of learning.

Analysis of mechanical stability for external fixation device Orthofix in the case of anterior-posterior bending is carried out in this paper. Device is applied to the lower leg for the case of unstable fracture. Real device is mea sured and 3D CAD model is developed. CAD model is used for numerical structural stress analysis which is car ried out using CATIA V5 software. Results for displacements are obtained for selected critical places on the device and for the place of fracture. In addition, values of principal and von Misses stresses are obtained and analyzed. Using obtained results, conclusions about mechanical stability of device are formulated.

The paper analyzes the stiffness of the Orthofix external fixation system at axial pressure load, applied to the lower leg in case of an unstable fracture. Based on the actual construction of the Orthofix fixator, its 3D model was formed, and then a structural analysis was performed in the CATIA V5 software system. The aim of this paper is to investigate the mechanical properties of Orthofix fixator. FEM analysis of the fixator revealed displacements at characteristic points of the structure and fractures. During the FEM analysis, it is possible to change the load values, all with the aim of obtaining the best possible information about the behavior of the fixator during installation and use by the patient. Based on the results obtained from the FEM analysis, it can be concluded that the Orthofix fixative shows very good stiffness, but also that it can be improved by using newer materials, such as composite or some alloys of titanium and aluminum.

The paper explores importance of rapid prototyping technology, as an important part of Industry 4.0, in product development and design process. Current state of this technology is explored in detail, with special focus of places and processes where this technology plays important role inside Industry 4.0. Paper answers several questionssuch as: does this technology have its future inside Industry 4.0, is this technology integral part of Industry 4.0 or just one aspect, has the time come to call this technology rapid manufacturing (of final products) instead of rapid prototyping (of prototypes)?Industry 4.0 implies rapid prototyping of final products, not only its prototypes. Main representative of rapid prototyping technology is additive manufacturing. Today, additive manufacturing technologies do not only serve for prototyping. They are becoming increasingly used for manufacturing of final fully functional products. Product development and design process inside Industry 4.0 must be adopted to new market demands which implies fast development and design and fast manufacturing. The time from initial concept design to the final product manufacturing must be as short as possible. The paper provides answers to the above stated questions. In addition, real examples of product development and design of prototypes and real fully functional products are presented, with a special focus on products and prototypes developed in Bosnia and Herzegovina.

U radu je obrađena tematika uloge tehnologija brze izrade prototipova u procesu razvoja i dizajna proizvoda. Kroz rad se pokušava staviti akcenat na trenutno stanje tehnologija brze izrade prototipova u sklopu Industrije 4.0. Da li tehnologije brze izrade prototipova imaju svoje mjesto u Industriji 4.0, da li su one osnova ove industrije ili samo jedan njen aspekt? Da li ih još uvijek možemo zvati tehnologijama brze izrade prototipova ili je vrijeme da ih zovemo tehnologije brze izrade proizvoda? Industrija 4.0 podrazumijeva brzu izradu proizvoda, a ne samo njihovih prototipova. Glavni predstavnik tehnologija brze izrade prototipova su aditivne tehnologije. Aditivne tehnologije prestale su da budu tehnologije kojima se izrađuju samo prototipovi, ove tehnologije se danas uveliko koriste i za izradu potpuno funkcionalnih proizvoda. Industrija 4.0 traži da se razvoj i dizajn proizvoda prilagodi novim rapidnim zahtjevima tržišta gdje se teži smanjenju vremena razvoja i dizajna uz istovremeno ubrzavanje proizvodnje, a sve sa ciljem da se u što kraćem vremenu dođe do finalnog proizvoda. U radu su dati odgovori na gore navedena pitanja i prezentovani praktični primjeri razvoja i dizajna prototipova i gotovih proizvoda uz upotrebu aditivnih tehnologija sa akcentom na proizvode razvijene, dizajnirane i izrađene u Bosni i Hercegovini.