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

The basic prerequisite for trouble-free assembly of moving structures is that the assembled structure has as many degrees of freedom as its function requires. In practice, we often encounter cases of statically overdetermined pairs. Designers often use them to increase the rigidity of products. This article describes a way to mitigate the consequences of problematic assembly in sliding pairs, which are often statically overdetermined. The article also addresses an important problem in assembly, which is repeated assembly accuracy, especially when designing assembly lines and automated and robotic systems.

Friction couplings for joining rebar are widely used in civil engineering and mechanical structures, including the construction of high-rise buildings, towers, bridges, overpasses, tunnels, dams, and other infrastructure. These friction couplings are mechanical elements that provide a strong and reliable connection between the components being joined by transferring loads through the friction force generated between the contact surfaces. This force is applied by the geometry of the friction coupling and the installation-induced clamping force. The primary factor governing the proper selection and application of a friction coupling is the cross-sectional diameter of the rebar, as the friction coupling must be designed to withstand the loads encountered under service conditions. In addition, environmental influences, particularly the difference in the coefficients of thermal expansion of the joined materials, represent an important consideration. Another critical factor is the installation process itself, as the performance of the friction coupling depends directly on proper installation. Therefore, comprehensive testing of the installed friction coupling is essential to ensure its reliable performance throughout its service life. This paper presents an original design solution for the development of a friction coupling for joining Ø25 mm rebar, developed through three successive design iterations. The proposed friction coupling is intended to ensure structural integrity under static and dynamic loading, including seismic loading and vibration. An initial prototype design was developed in accordance with the applicable technical standards and validated using the Finite Element Method (FEM) to evaluate its load-bearing capacity under static loading conditions and identify potential stress concentrations. The prototype models were manufactured using the Fused Filament Fabrication (FFF) additive manufacturing process with the support of CAD/CAE systems. The friction coupling was ergonomically designed through mass and shape optimization.

In recent decades, it has become commonplace to automate assembly operations, often linked to production technologies within a single flexible production and assembly system. Assembly has a significant impact on global production, both in terms of its share of the total production cost of assembled products and in terms of the number of people employed in this area. The challenge for scientific and technical intelligence is to rapidly acquire production and assembly know-how to achieve target parameters in the shortest possible time. The use of all machinery and equipment forces people to think about how to use energy in the most efficient way, with the least possible loss, either in terms of money or in terms of energy. Every year the cost of energy increases, whether due to depletion of supplies or climate changes.
Compressed air leaks are a serious problem in many industrial and manufacturing environments. These leaks not only increase operating costs but can also have a negative impact on the environment and the health of workers. Compressed air is the most expensive medium and when all basic costs are included, compressed air is many times more expensive than the equivalent of electricity. Therefore, it is necessary to analyse how to prevent high losses in the industry.

Electronic assembling is strongly automated. In 1980 the use of SMD technology for electronic assembly began on a mass scale. This technology is currently used in more than 90% of the cases. It requires a precise passing of SMD components so that it can assemble with high speed and precision. The technology is hardly applicable for non-standard component such as contact components. In the production of flame detectors by the firm of “UniPOS” non-standard contact components are used. These components have to be positioned and soldered precisely because after that there will be no opportunity for automated assembling of the final products. At first these components were put by hand and they were soldered by SMD technology. This led to a lot of labor expense, a low quality and a lot of rework, which made the products more expensive. By a vibration and a specially created strip for leading and positioning the contact elements conditions for automated SMD assembly were created. This enabled a large decrease in the prime cost of the products and an increase in the productivity of the whole production.

Robot assembling is flexible and it enables a stable and high-quality assembly. It enables a constant improvement and an easy multiplication. This report represents an idea for adding functionalities in a robot complex for assembling flame detectors in the firm “UniPOS” and it analyses the benefits of this. The main aims for a development of the existing robot complex for assembling are: decreasing the production prime cost; reducing the manual labor that is connected to loading components; increasing the use of the robot complex; reducing the cycle time and increasing the productivity of the robot complex; increasing the quality of the manufactured products. The additional functionalities are accomplished in parallel with the main ones in assembling and they are at the expense of running all robots in the complex and their use only for assembling (not for loading the components).

While designing a Cardan coupling it is necessary to assess the assembly-ability of its components as well as to ensure that they do not interfere with each other during normal operation. In practice, this is done by use of prebuilt sample models, where everything is checked by experimenting. The authors share herewith their idea for developing a new approach to designing Cardan couplings, where all operations are performed in an automated way as early as the design stage.