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

ROUGHNESS, AMPLITUDE DISTRIBUTION AND BEARING AREA CURVE DURING CNC MACHINING OF Al7SiMg

Nicușor BAROIU — 2025-03-24

The paper analyzes the roughness of surfaces obtained by CNC machining on a
HAAS VF-1 center, using an Al7SiMg type material. The study presents general
notions about microgeometrical precision, roughness parameters and their
influence on the functioning of machine parts, such as wear resistance, corrosion,
adjustments and fatigue limit. In the experiments, three faces of a part called a
hydraulic distributor were processed, using drill, cylindrical-frontal end mill and
frontal end mill tools. The roughness was measured on various surfaces using the
Surtronic SJ-210 Mitutoyo equipment, which provides precise results in numerical
and graphical form. The results include roughness values and graphs for each
analyzed surface, complemented by graphical representations, such as histograms
and distribution function curves. The study also highlights the interaction between
CNC machining parameters and surface quality, providing useful information for
optimizing the machining processes of aluminum alloy materials.

INFLUENCE OF CUTTING PARAMETERS ON THE ROUGHNESS OF MACHINED SURFACES

Virgil Gabriel TEODOR — 2025-03-24

Aluminum-based alloys are increasingly used in the aeronautical, automotive,
defense, etc. industries. This has led to the development of research on the
machinability of these types of materials. Although aluminum is not considered to be
a material characterized by good machinability, there are among its alloys some
that stand out for this quality. This is the case of duralumin 2024 T351, which is an
alloy characterized by good mechanical strength, relatively high hardness and
corrosion resistance. These characteristics, combined with a low density of the
alloy, cause the material to be widely used in the aeronautical, automotive and
defense industries. Among the methods of processing parts made from 2024 T351,
machining is also used. One of the indicators of the quality of this type of processing
is the roughness of the chipped surface. In this paper we aim to identify which of the
parameters of the machining process has a more important influence on the
roughness obtained.

ANALYSIS OF THE DISTRIBUTION OF AXIAL FORCE VALUES IN DRILLING, DEPENDING ON MACHINING PARAMETERS

Virgil Gabriel TEODOR — 2025-03-24

Drilling is one of the most widely used material machining processes, with
applications in various industries such as machinery manufacturing, automotive,
and aerospace. One of the factors that influence the quality and efficiency of the
machining process is maintaining a constant cutting force.
Maintaining the cutting force at a constant level during drilling is essential for
ensuring dimensional precision, surface quality, tool durability, operational
efficiency, and safety. Implementing advanced technologies such as automated
control systems and force monitoring can significantly contribute to process
optimization and risk reduction. This ensures high-quality production with reduced
costs and increased productivity.
In this study, the axial force distribution during the drilling of an aluminum
alloy, 2024 T351, was determined, with measurements conducted for three
combinations of machining parameters. A total of 27 holes were machined using
drill bits with diameters of 6, 8, and 10 mm, cutting speeds of 50, 60, and 70 m/min,
and feed rates of 0.1, 0.25, and 0.4 mm/rev.
The axial force measurement was performed using a Kistler dynamometer
available in the Manufacturing Engineering Department of the Faculty of
Engineering at the “Dunărea de Jos” University of Galați.

OUTSOURCING STRATEGIES IN MANUFACTURING PROCESSES OF BEARING RINGS

Afteni MITICA — 2025-03-24

In the last decades the globalization of businesses has led to new approaches
regarding the usage of resources. Identification of the optimum solution for
resource planning and usage requests some market research. This is necessary to
select, evaluate and qualify the suppliers. An important job in this feasibility
evaluation process is the analysis of the supplier capability to manufacture,
control and delivery the products according to customer specifications. The
integration of the outsourced process in the company flow diagrams requests
analysis and identification of the products and process requirements. This paper
proposes a new method that can be used to integrate the outsourced processes or
phases in the manufacturer management system. A case study to assess the
feasibility of outsourcing as a part of the manufacturing process of components
for the bearings used in railway industry is presented. The study was developed
based on actual data collected from the industry.

COMPARATIVE ANALYSIS OF SURFACE PREPARATION TECHNIQUES IN THE MARITIME INDUSTRY FOR CORROSION PROTECTION

Laurențiu MARDARE — 2025-03-24

This study highlights the importance of abrasive blasting in the maritime
industry for the durability and safety of marine structures. Abrasive blasting is
employed to clean and prepare metal surfaces by removing rust, impurities, and old
coatings, facilitating optimal adhesion of anti-corrosive coatings that protect
against saline corrosion. Eco-friendly abrasives, such as garnet, represent a
sustainable choice, reducing health risks for workers and preventing soil and water
contamination. Additionally, classical abrasive blasting is compared with the use of
rotary abrasive discs, which allow for more precise cleaning control while
minimizing dust and noise.
The analytical methods employed to evaluate the efficiency of the surface
preparation process include adhesion testing, roughness measurement, contact
angle measurement, and optical microscopy. These techniques enable a detailed
assessment of the characteristics of treated surfaces.

"STEM FOR INCLUSIVE SCHOOLS" MEETING – AN IMPORTANT STEP TOWARDS INCLUSIVE EDUCATION

Virgil Gabriel TEODOR — 2025-03-24

Between 25-29 November 2024, the "Dunărea de Jos" University of Galați
hosted the international meeting within the "STEM for Inclusive Schools" project, a
learning, teaching and training activity (LTTA). The event brought together partners
from Romania, Germany, Poland, Portugal and Turkey, with the main aim of
developing transversal skills and promoting inclusive educational practices in the
field of STEM (science, technology, engineering and mathematics)

NUMERICAL REPRESENTATION OF OBJECTS – REPRESENTATION OF 3D BODIES

Răzvan Sebastian CRĂCIUN — 2025-03-24

We are familiar with everything necessary to create the image of a point or a
line in digital environment, we can represent many points in 2D and in 3D. So that
these sets of points projected in a design software can be transformed into somewhat
suggestive images of solid objects, it is necessary to know the order in which certain
points must be joined together by segments or curves, thus suggesting to the
operator constructive surfaces. The information needed to build a body image is
stored in a "database", having a very well-defined ordered structure of numbers and
characters. The structure of the database strongly influences the speed of work, the
required memory of the program, the flexibility of the program, as well as the ease
of writing the program. This paper presents some common ways of organizing data
to generate different types of simple representations in ascending order of
complexity.