|SCIENTIFIC DISCIPLINARY SECTOR||ING-IND/15|
|MODULES||This unit is a module of:|
The course provides the basic knowledge, according to ISO standards, for the correct interpretation and understanding of technical drawings and for drafting, using a CAD software, mechanical components with geometry description and all further information (tolerances, processes, materials, etc.) necessary for their implementation (tolerances, processes, materials, etc.).
The purpose of the teaching is to introduce the student to the industrial drawing which is a universal visual language that conveys the way something works or how it is built. It will be explained that technical drawings may include two-dimensional (orthogonal) plans, sections and elevations or may include three-dimensional or exploded projections. They can be drawn to scale by hand or prepared using CAD (Computer Aided Design) software. To convey the precise meaning of the information, it will be clarified that technical drawings include dimensions, annotations and symbols which, to ensure their concise and unambiguous meaning, must be consistent with industry standards; furthermore, information on technical specifications included in technical drawings should never be duplicated as this can become contradictory and confusing.
Attendance to lectures, participation in computer classroom activities and individual study will allow the student to:
• learn the general aspects of the design
• acquire the technical terminology used in the design
• master the methods of representing real objects through orthogonal projections and with the use of sections according to the European ISO method
• correctly indicate the dimensions, dimensional tolerances and geometric and microgeometric tolerances
• knowing how to express couplings between pieces with clearance or interference in the shaft basis or hole basis system, identifying the correct position and tolerance class
• know and master the CAD tools for the creation of graphic primitives, their manipulation and modification and for the designation of dimensions, tolerances and machining
• create two-dimensional A4 tables with a CAD software in which mechanical parts are represented with the technical specifications necessary for their manufacturing
The course consists of lectures and exercises in the computer room.
The lessons introduce the UNI ISO standard for the representation of objects in an unambiguous manner and the indication of dimensions, dimensional, geometric and microgeometric tolerances. Furthermore, they present the terminology and basic rules for industrial technical drawing with the appropriate symbology to indicate threads, gear wheels, bearings, etc. The principle of maximum material and the need for envelope are also illustrated as exceptions to the principle of independence between dimensional and geometric tolerances.
The exercises are meant to explain the commands of a CAD software for the creation of A4 drawings in which a mechanical part is represented according to the European orthogonal projections method. In order to facilitate the learning of the representation methods of 2D drawings on the computer, the students, who can work in pairs, are assigned themes that they develop independently. The idea is to exploit the techniques of learn by doing and learn by trial and error. The teacher guides and assists the students without interfering with their reasoning and about half an hour before the end of the exercise asks students who wish to show their work to the whole class so that errors are highlighted and corrected in real time.
EU Machinery Directive and Italian D.Lgs. 81/2008.
Outlook on Design for Assembly and Manufacturing.
Standardisation: National and International standards. Drawings types. Representation of the shape and size of a mechanical part: the graphic model. Orthogonal projections, sections, dimensioning and relative rules. Overview on other types of projections (axonometric, trimetric, slanted). Tolerances: dimensional, geometrical, surface finishing tolerances. Matings: base-shaft, base-hole systems. Maximum material condition. Envelope principle. Threads. Classes of bolts and nuts. Bearings: types, mounting systems, simplified representation. Gaskets. Devices for dismountable mechanical joining (keys, tapered keys, pins, transversal pins, set-screws, “Seeger” rings, toothed matings) and for fixed assembly (riveting, welding, graving). Guidelines for the shape of mechanical parts in relation to the process used to build them.
Practice: practice will be done in computer classroom by using the CAD software Microstation.
Office hours: The teacher is available for the students at the end of each lesson or via a MS Teams meeting.
LUCIA CASSETTARI (President)
ROBERTO RAZZOLI (President)
GIOVANNI BERSELLI (President Substitute)
All class schedules are posted on the EasyAcademy portal.
The exam is divided into 2 tests:
A graphical computer test, which involves the execution of a constructive design using the 2D CAD MICROSTATION v8i. The graphic test takes place in the computer room (duration of the test: 2 hours) and the result of the test must be ≥ 18/30.
A quiz (30 questions to be answered in 45 minutes using the Safe Exam Browser tool), which is an assessment of the theoretical knowledge indicated in the course program.
N.B. The written test, if sufficient, is valid for the whole solar year. The quiz can be taken in any official appeal.
It is mandatory to apply for the test using the online mode (from the University portal services to students), AT LEAST 5 DAYS BEFORE the start of the test.
Within the assigned term, the drawing must be saved as a PDF file and uploaded along with the DGN file onto Aulaweb.
It is possible to consult books and / or manuals.
The results will be given on Aulaweb.
The quiz if not passed (or rejected) does not cancel the written test score. The positive results obtained in the graphic tests are valid for a calendar year.
The final grade is the average of the quiz and written test score.
Files containing the sheets in A4 and A3 format and the Microstation seed file settings are available on Aulaweb.
Upon delivery of the written test, the evaluation of any previous test is lost.
The examination procedures, its preparation and the degree of deepining of each topic will be illustrated during the lessons and reported on Aulaweb.
The written examination consists in the realization of a 2D table with dimensions and tolerances of a mechanical part of which a three-dimensional representation is provided. The student must be able to represent the proposed object unambiguously, maintaining its proportions, according to the European method of orthogonal projections; must provide the minimum number of views necessary to guarantee the workable realization of the piece; he or she will have to arrange the dimensions in sufficient and not redundant manner and to indicate the tolerances according to the required specifications in the examination text. He or she must be able to use the appropriate styles and line weights; must be able to designate a coupling in the hole-basis or shaft-basis system.
The quiz will focus on the topics covered during the lectures and has the purpose of assessing not only if the student has reached an adequate level of knowledge, but also if he or she has acquired the ability to deal with logical problems that will be posed during the quiz.