Computer Numerical Control

Code:

EM0045

Acronym:

CNC

Keywords
Classification	Keyword
OFICIAL	Automation

Instance: 2007/2008 - 1S

Active?	Yes
Responsible unit:	Automation, Instrumentation and Control Section
Course/CS Responsible:	Master in Mechanical Engineering

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
MIEM	14	Syllabus since 2006/2007	5	-	6	56	160

Teaching language

Portuguese

Objectives

Background:
The CNC technology is a fundamental technology of the modern factories mainly in the manufacturing industry. So it is essential for a mechanical engineer specialized in the automation area to be familiar with this technology, its potential, its applications and how to programme and operate it. This unit aims to prepare the students to be able to recognize the suitability of applying the CNC technology to specific industrial processes as well as to prepare them to design and implement CNC based control systems.

Specific Aims:
To provide the students with the necessary tools so they can be able to understand, design and implement flexible manufacturing equipments based on CNC technology, integrate CNC technology with other production systems as well as with Computer Aided Design and Computer Aided Manufacturing Systems.

Previous knowledge:
Technical Design for mechanical engineering – Mechanical technical design.
Systems dynamics – Automatic control.
Design of mechanical structures – Structures design and dimensioning.
Computer Aided Design and Computer Aided Manufacturing – Computer Aided Design and Manufacturing.
Sensors, transducers and instrumentation – Electricity and instrumentation.
Programmable Logic Controllers - Industrial computing.

Percentual Distribution:
Scientific component (establishes and develops scientific bases) – 30%
Technological component (apply to design and process operation) - 70%

Learning outcomes:
Knowledge and Understanding – recognize the specific attributes of the CNC technology and in what conditions and requirements it is suitable as a computerized control systems.
Engineering Analysis – Analysis and formal specification of the requirements of any practical application of a CNC system.
Engineering Design – Design of the mechanical systems as well as of the CNC solution for a particular situation in which this type of technology is the most suitable.
Investigations – Seek for the most suitable components and solutions available in the market for building a tailor made mechanical and control system.
Engineering Practice – Implement CNC based control systems.

Program

Fundamentals of Numerical Control; CNC technology as a building block of FMS; CNC technology vs mass production systems; trends.
Industrial applications of CNC technology.
Architecture of the CNC; building blocks; functional blocks; interface level; processing level; process control level; axis control.
Point to point control; Contouring control; Adaptive control.
Generation of tool trajectory: reference systems; resolution; systematic and variable errors; Errors compensation. Tolerance of trajectory.
Design of CNC machines and manufacturing systems: typical architectures; movements; rotating and linear axis; automatic tool change systems; automatic part load/unload systems; tool monitoring systems; tool dimension measuring systems; tool wear measuring; tool breakage detection.
Structure of NC language; ISO codes; Computer Aided NC programming; Generation of NC programs using CAD/CAM systems; Trends; Examples of NC programming.
Integration of CNC with other systems at the information exchange level control level.
Criteria for assessment and comparison of CNC equipments; Performance evaluation.

Mandatory literature

Thyer, G. E.; Computer numerical control of machine tools, N. ISBN: 0-7506-0119-1
HMT Limited; Mechatronics and machine tools, N. ISBN: 0-07-134634-1

Complementary Bibliography

Leatham-Jones, Barry; Introduction to computer numerical control, N. ISBN: 0-582-29040-6
Sava, Michael; Computer numerical control programming, N. ISBN: 0-13-156084-0

Teaching methods and learning activities

Room classes to expose concepts and give information regarding CNC technology.
Elaboration of solutions for case studies concerning practical applications of CNC technology.
Laboratory classes to practice the use, parameterisation and set up of CNC as a control system of a 3-axis equipment.
Demonstration of existing CNC equipments for machining, grinding, erosion, and sheet metal forming.

Evaluation Type

Distributed evaluation with final exam

Assessment Components

Description	Type	Time (hours)	Weight (%)	End date
Subject Classes	Participação presencial	56,00
	Total:	-	0,00

Eligibility for exams

75% of presences registered on the taught classes.

Calculation formula of final grade

- 60% final written exam
- 40% continuous evaluation based on the results of the case studies.

Examinations or Special Assignments

Propose solutions for three case studies.

Special assessment (TE, DA, ...)

Written exam.

Classification improvement

This will be done accordingly to the General Evaluation Rules of FEUP.

Observations

Language of instruction: Portuguese