Tolerancing of Mechanical Systems


Global and integrated vision of dimensional and geometric characteristics of a product in terms of function, production and inspection:

i) Preparation of mechanical design of the simple and complex products for manufacturing and assembly, through proper specification of their key-characteristics represented by tolerances (dimensional and geometrical).

ii) Preparation of industrialization of products to reduce cost and time.

iii) Preparation of dimensional and geometric control.

General characterization





Responsible teacher

António José Freire Mourão


Weekly - 4

Total - 62

Teaching language



It is desirable that students take the following subjects:

- Mechanical Engineering Drawing;

- Introduction to Technology and Mechanical Processes;

- Foundry and Welding Technologies;

- Mechanical Behaviour of Materials;

- Solid Mechanics I and II;

- Cutting Technologies;

- Design Theory and Methodologies;

- Metal Forming Technology;

- Machine Design


Several documents prepared by the professor.

ANSELMETTI Bernard, “Tolérancement Volume 2: Méthode de cotation fonctionnelle“ Hermès – Lavoisier, 2003.

ANSELMETTI Bernard, “Tolérancement Volume 3: Cotation de fabrication et métrologie“ Hermès – Lavoisier, 2003 .

Thomas J. Drozda (Editor), Tool and Manufacturing Engineers Handbook – Vol 1: Machining, Society of Manufacturing Engineers, 1983.

Edward Roth, Integrated product design and manufacturing using GD&T, Marcel Dekker, 2003.

Lowell W. Foster, Geo-Metrics IIIm – The metric application of geometric tolerancing techniques, Addison-Wesley Publishing Company, Inc., 1994

Teaching method

Presentation of theoretical contents followed by analysis of real problems and resolution of project cases, in an environment involving teacher and students.

Evaluation method

A test and a project.

The project is carried out in groups (3 elements) and will have a presentation, with discussion.

The frequency is given by the realization of the project.

Final classification:

CF = 40% of test grade + 60% of project grade

You will have to take the exam if CF < 10 values, and in this case:

Final grade = 40% of the exam grade + 60% of the project grade

Subject matter

1. Functional dimensioning and geometrical tolerancing - Problem of functional dimensioning. Survey of functional requirements. Chains of functional dimensions. Analysis and synthesis of tolerances with worst-case and statistical models. Geometric tolerancing. Sequence of the datum. Material conditions. Calculation of geometric tolerances. The hierarchy of subassemblies in the assembly.

2. Dimensioning and tolerancing to the operations of manufacturing and assembly - Manufacturing specifications. Allocation of tolerances. Modelling the areas of dispersion. Dimensions transfer from design to manufacturing. Manufacturing simulation. Defining intermediate stages. Indicators of processes capabilities. Design principles of fixturing and clamping systems for machining.

3. Measuring and control - Principles and methods of measuring. Metrology equipment. Design of functional gages. Coordinate metrology.


Programs where the course is taught: