Annals of ”Dunarea de Jos” University of Galati, Fascicle V, Technologies in machine building

A PRODUCT DEVELOPMENT PROCESS AND ITS MANAGEMENT. AN ENGINEERING STUDENT LABORATORY

Maria Neagu — Fri, 22 Mar 2024 00:00:00 +0200

This paper reveals the project management techniques and methods that the engineering student could develop as an exercise as well as a proof of the complete understanding of a product development steps. The process of vehicle development is used as an example. The Pert diagram, the probabilities and the minimum costs calculation, the human resources management and the risk management analysis are presented.

A PRODUCT DEVELOPMENT USING THE ROBUST DESIGN CONCEPT AND THE TAGUCHI METHOD

Maria Neagu — Fri, 22 Mar 2024 00:00:00 +0200

The robust design of a new product is exemplified in this paper as an exercise that every engineering student could do for a better understanding of the DFSS (²Design For Six Sigma²) process. The design of a new paper binder is presented through several steps that make the process easy to follow and to understand by the student. Both classical mathematical pursuit and modern technology are presented as viable ways of solving the problem.

FINITE ELEMENT ANALYSIS OF A LONGITUDINAL TRANSMISSION SYSTEM

Valentin Amorțila, Costel Humelnicu, Mădălina Rus, Silvia Vereșiu — Fri, 22 Mar 2024 00:00:00 +0200

This paper addresses how a longitudinal transmission system of a car could be analyzed using Autodesk Inventor software. The longitudinal transmission, also known as a driveshaft or cardan shaft, is a system used in rear-wheel-drive or all-wheel-drive vehicles where power is transmitted from the engine to the rear axle or to both axles. During the operation of the longitudinal transmission, various loads can lead to the wear and tear of the universal joints, resulting in failures or even the destruction of the system. To prevent these issues, we considered it necessary to analyze the modelled driveshaft using Inventor based on von Mises stresses and the safety factor. The material used in this study is cast steel with the following properties: Mass Density 7.85 g/cm³, Yield Strength 250 MPa, Ultimate Tensile Strength 300 MPa, and Young's Modulus 210 GPa. The results obtained for different angles of inclination of the universal joint axes lead to the conclusion that the positioning of the driveshaft significantly influences the durability of the longitudinal transmission system.

ANALYSIS OF THE BRAKE CALIPER POSITIONING IN VEHICLES

Valentin Amorțilă, Constantin Georgescu, Cristian Munteniță — Fri, 22 Mar 2024 00:00:00 +0200

This paper aims to analyze the positioning of the brake caliper on vehicles, considering the most common situations, namely in front of or behind the brake disc. The positioning of the brake caliper on cars depends on the design and configuration of the brake system specific to each vehicle model. This positioning is determined by the engineers and designers responsible for the vehicle's safety, considering factors such as chassis geometry, weight distribution, desired braking performance, and other relevant technical factors. Generally, the brake caliper is located near the brake disc so that it can apply the necessary pressure to efficiently stop the wheels. Typically, in the case of disc brake systems, the brake caliper is positioned in front of the wheel, near the brake disc. There are cases where the positioning is behind the disc. Starting from this controversy, we considered it opportune to analyze the two cases on a stand that replicates the brake system. Thus, the two situations were analyzed using pressures of 2, 4, and 6 bars in the brake pipe. The variations in brake disc temperatures and braking distances were determined for each case to conclude the positioning of the caliper. The decision regarding the placement of the brake caliper in front of or behind the wheel is made by the vehicle manufacturer based on technical specifications and the desired performance of the brake system.

THE INFLUENCE OF A FLY-WHEEL IN A ROTOR-BEARING SYSTEM ON ITS CRITICAL SPEEDS

Doina Boazu — Fri, 22 Mar 2024 00:00:00 +0200

The paper highlights the influence of the presence of a fly-wheel on a rotor-bearing system in the removal of the critical speed in a rotational speed interval. The stiffness of the bearings and the damping introduced by them, the gyroscopic effect on the system elements are taken into account. The quantification of the dynamic influence of the fly-wheel is carried out with the help of Campbell diagrams in the finite element analysis program Ansys Workbench, taking into account gyroscopic effects.

QUALITY ASPECTS IN THE WELDING OF SOME ELEMENTS OF MICRO-MOTORS IN AUTOMOTIVE AND HOUSEHOLD APPLIANCES INDUSTRY

Nicușor Baroiu, Daniela Mâncilă, Marius Corneliu Gheonea, Virgil Gabriel Teodor — Fri, 22 Mar 2024 00:00:00 +0200

In the automotive and household appliances industry, there is a permanent concern to find fast and efficient welding methods and technologies, pressure welding being one of the usual joining methods, due to the minimum qualification requirements, cheap equipment, ease of control, high speed of operation, repeatability and suitability for automation or robotization for inclusion in high production assembly lines. In the paper, quality aspects are described in spot welding of some elements of micro-motors in the automotive industry and household appliances by using tools that allow highlighting the fact that the process is controllable from a statistical point of view, concerning two micro-motors from the production flow.

EXPERIMENTAL DETERMINATION OF TORQUE FOR THE DRILLING OF AL7SIMG ALLOY

Virgil Gabriel Teodor, Răzvan Sebastian Crăciun — Fri, 22 Mar 2024 00:00:00 +0200

The productivity of a machining process is closely related to the value of the cutting force. For the calculation of the cutting forces, a series of models have been developed to allow the determination of these forces according to the machined material and the specific conditions in which the process is carried out. Usually, for a better approximation of the value of the cutting force, the unitary specific cutting force is used, which depends on the machined material. For common materials, the values of specific unitary cutting forces are presented in the specialized literature, but for less frequently used materials, for example, those with reduced machining properties, the respective values are difficult, sometimes impossible to find. In this paper, determining the unitary specific cutting force for an aluminium alloy with a high silicon content is intended, recognized as difficult to machine. The determination of the value of this force is done starting from the measured values of the torsional moment at the drills.

CONTROL OF DEVIATIONS FROM CIRCULARITY WHEN DRILLING POLYMERIC MATERIALS

Fri, 22 Mar 2024 00:00:00 +0200

Polymeric materials represent synthetic macromolecular products, from which objects of various shapes can be manufactured, through mechanical or thermal processing. These materials are used in various industries due to their versatility and ability to adapt to various applications. The paper presents an analysis of deviations from circularity in the drilling process of three types of polymeric materials: PA6 (polyamide), PEHD (high-density polyethylene) and POMC (polyacetal). The main purpose of this analysis is to evaluate and measure the deviations from circularity in the drilled plates using specific drills on the EMCO MILL 55 CNC machine and the precise determination of these deviations is realized with the help of the Sinowon 3D measuring machine. In the context of the processing of polymeric materials, both technical performance criteria and their associated factors in drilling operations are examined. In the study, two types of helical drills were used, with two rectilinear cutting edges, having different diameters, Ø8 mm and Ø10 mm, made of high-speed steel.

TRANSNATIONAL PARTNER MEETING OF THE PROJECT "STEM FOR INCLUSIVE SCHOOLS"

Virgil Gabriel Teodor — Fri, 22 Mar 2024 00:00:00 +0200

The first transnational meeting of the partners of the Erasmus+ project KA220-NW-23-30-151162.