In industry and in particular in the field of mechanical engineering, technical drawing is the language that engineers use in order to define, detail and communicate their design and manufacturing choices. In accordance with its rules, defined by standardized conventions and methods of graphic representation, technical drawings contain manufacturing and testing information of machines and related mechanical components.
The course aims at providing students with the basic knowledge, according to ISO standards, for the correct interpretation, understanding and execution of technical drawings via CAD software, with particular reference to the components used in the nautical industry (description of geometry, tolerances, processes, materials, etc.). In addition, it shows the symbolic representations of the main structural elements, providing indications for the correct selection of components.
The teaching aims to provide fundamental elements on the graphic representation using orthogonal projections , sections and units . Introducing the use of the computer to create models and drawings with special practical applications .
Basic introduction to general industrial aspects
Methods of representation and orthogonal projections In-depth study of some particularly interesting topics for the mechanical engineer
Sections, dimensioning, micro / macro geometric tolerances bolt and welded connections
Basic knowledge of how a computer works and of Windows® operating system.
The course consist in 13 frontal lessons that covers the whole program of the course, usually held in the first paret of the weekly timetable oof the course. The second part consist in a practice session using the CAD tool MICROSTATION V8i. Each exercise consist in a technical drawing to be made usign orthogonal projection method. The solution of the proposed exercise is presented the next lesson. All the exercises carried out in the classroom are indicated with the letter A, for a total of 7 exercises (A1-A7). The exercises carried out in classroom represent an essential part of the overall course and can be downloaded directly from the course web page (www.aulaweb.unige.it). The course also comprises seven exercises (D1-D7) to be independently carried out at home (similarly to the exercises carried out in the classroom). The homework exercises can be downloaded directly from the course web page (www.aulaweb.unige.it)
1. Introduction
- General: purpose of technical drawings. Drawing tools. Standards. Formats and sheet folding (UNI EN ISO 5457 and UNI 938). Representation scales. Basic geometric constructions.
- Projections: Projection Methods (UNI EN ISO 5456). Orthogonal projections. True form: rotations and reversals. Planar sections of solids.
- Axonometric projections: isometric orthogonal projections: isometric, dimetric and trimetric; Unified applications and orthogonal axonometric projections.
2. Standards for technical drawing
- Technical product documentation (UNI EN ISO 3098)
- General principles of representation: basic conventions for lines. Fundamental conventions and applications for construction lines. Lines used in mechanical and industrial engineering drawings.
- Views and Sections (UNI ISO 128 and UNI 3972): fundamental conventions for views. Fundamental conventions for cuts and sections. Views and sections in mechanical and industrial engineering drawings. General conventions for surface representation in case of sections and cuts. Lines for the material representation in sectioned parts.
- Dimensioning and selection of reference (UNI EN ISO 1119 and 3040, UNI ISO 129): General principles. dimensioning and related rules. Special conventions. Conical elements. Series of taper and cone angles.
3. Technical Drawings and Manufacturing Technologies
- Elements of Material and Machining Technologies.
4. Tolerances and surface roughness
- Tolerances: normal numbers; the ISO system of tolerances, tolerances and deviations, fundamental tolerances, fundamental deviations; Hole-based and shaft-based coupling systems; selection of tolerances; deviations for dimensions without indication within machined parts; series of tolerated dimensions.
- Surface roughness: Definition, measurement of roughness, general design rules; considerations on the surface finish: roughness and machining, roughness and tolerances; indication of the roughness on technical drawings.
5. Connection between components
- Fasteners: Unified threads; threaded connections (screws, studs, nuts, bolts); connections through screws; devices against loosening; examples of applications.
- Permanent connections: nails and rivets; welded connections; representation of welds and graphic related symbols; examples and applications.
6. The computer aided drafting
- 2D CAD - MICROSTATION V8i:CAD workstation; generation of geometries; properties of elements and their modification; auxiliary functions; generation of the drawings; dimensioning.
Recommended texts
Consultation texts
Ricevimento: Students may contact the professor by e-mail to ask an appointment.
DIEGO TORAZZA (President)
GIOVANNI BERSELLI
https://corsi.unige.it/8721/p/studenti-orario
The exams is divided in 2 parts: the final grade is the average rating of the oral and graphical exam tests.
1. Written session It is compulsory to register using the on-line tool (from the University portal - Student Services), at least 5 days before the test. Students can be divided in groups one group in the morning and one in the afternoon. If the total number of students is very high the exam will be carried out over two days. Each students will receive a mail the day before exam with his date/time. The test consist in a technical drawing of a component by using the 2D CAD MICROSTATION V8i using a personal computer. Within the prescribed exam timing (3 hours), the drawing must be saved on a USB memory support in .dgn format and given to the teacher. It is possible to bring along handouts and / or manual. Results will be published on Aulaweb. The written test is valid for the entire calendar year. The related oral exam may be seated in any official exam date. When the solution of the graphical test is handed in, any evaluation potentially achieved in previous exam session is lost.
2. Oral session The outcome of the written sessionj must be ≥ 18/30. It is mandatory to register online (https://servizionline.unige.it/studenti), 5 DAYS IN ADVANCE. Each enrolled student will then receive an email warning, reporting time and date of the oral test. In this session the student have to answer 3 questions about the theoretical part of the course, as well as a discussion of the drarings D1-D7 to be handed in before the oral test. The exercises performed at home (drawings D1-D7) must be delivered during the oral exam (preferably printed or, alternatively, in .dgn format on a USB stick). The exercises performed on A3 format can be printed on A4-size sheets, by imposing a scale 1: 1.4 within the Print window of Microstation. A negative result on the oral examination does not imply that the (eventually) positive mark on the graphical test will be lost.
The written exam will assess the ability to draw in orthogonal projections and to dimension according to regulations (including geometric tolerances and roughness) an object assigned in axonometry. The oral exam will allow to verify the knowledge of the theoretical topics. The evaluation parameters concern the ability to read and interpret the regulations, as well as to apply them correctly during the drawing.
Ask the professor for other information not included in the teaching schedule.
