Introduction to Precision Engineering

INTRODUCTION TO
PRECISION
ENGINEERING
Prepared by:
Gregorio, Seth G.
Hindap, Jerome F.
Magbanua, Shembelle G.

WHEN DOES PRECISION ENGINEERING
STARTS?
Precision engineering was first published in January 1979; since 1986 it has
also been known to many of its readers as the Journal of the American Society of
Precision Engineering. Now with effect from 2000, it assumes a new look,
proudly proclaiming itself the Journal of the International Societies of Precision
Engineering and nanotechnology.

WHAT IS PRECISION ENGINEERING?
Precision engineering is a subdiscipline of electrical engineering, software
engineering, electronics engineering, mechanical engineering, and optical
engineering concerned with designing machines, fixtures, and other
structures that have exceptionally low tolerances, are repeatable, and are
stable over time.
It is defined as painstaking attention to detail and requires knowledge of a
wide variety of measurement, fabrication and control issues.
Increasing the precision-the accuracy and repeatability of a mechanism or
process is critical to our country’s competitive position in the world of high
technology

It is the discipline of designing a machine or instrument so it can
maintain, measure, or move to position of follow a path with a level
of accuracy.
It is also the body of knowledge, wisdom and techniques used to
design such a machine or instrument itself.
It is the design and building of complicated tools and instruments
whose parts must be exactly right in size and position.

PRECISION METROLOGY
Precision Metrology (a.k.a Dimensional Metrology) is the science of calibration of equipments and
using physical measurement equipment to quantify the dimensions from and of any given object (etc.
size, length, angle, distance). The end goal of precision metrology will be to achieve a high level of
competency in the 4 following aspects of measurements:
Aspects Definition
Accuracy The degree of exactness which the measurements
corresponds to the real dimensions of the part.
Precision The ability of the measurement to be consistently
reproduced
Reliability The consistency of accurate results over consecutive
measurements over time from the equipment
Traceability The ongoing validations that the measurements
correspond to the real dimensions of the part

PURPOSES OF PRECISION ENGINEERING
There are a few terms that you must first become familiar with so you can understand what
precision engineering is all about.
▪ The first term is dimension, which basically means any physical factor that can be
measured. This all includes speed, humidity, temperature, space, distance and so on.
▪ The second term is low tolerance which is used in engineering a lot. This refers to being
unable to function if one of these dimensions is changed or altered in any way.
▪ The last term that is used is overall stability, which as you guessed it, means that the whole
engineering design is highly tolerant.

PURPOSE AND PERFORMANCE
Performance of a precision machine or instruments is usually expressed in terms
of accuracy of the output while subject to a certain constraints such as weight or
a harsh operating environment.
For example: A CNC mill – accuracy is the deviation of machine surfaces from
theoretically perfect for.
Performance may also be defined in many ways that are more complex function
of the arrangement of and interaction between the machine or instrument’s
components.

SUBDISCIPLINES OF PRECISION ENGINEERING
Precision machine design - is typically concerned with using energy to
produce a useful action or output with great precision, such as machining a
part.
Optomechanical engineering - is typically concerned with holding optical
elements in precise locations without distorting their optical surfaces. Motion
can be involved either as an active function – such as in an optical zoom
mechanism – or as passive compensation – such as in a lens that uses
materials with different coefficients of thermal expansion to compensate for
changes in focus with temperature (a form of a thermalization).

DIFFERENT FACTORS OF PRECISION
ENGINEERING
1. Accuracy
▪ Accuracy is the most important in precision engineering
▪ CNC milling and turning milling machines however have helped to maintain a
good level of accuracy
2. Precision
▪ Precision is all about having a system that can repeat or reproduce
measurements in unchanged conditions so that you're able to get the same
result.

3. Predictability And Control
▪ Each product is worked on with the same tools, by the same
program in the same conditions so that the predictability and
precision engineering can be closely maintained.
4. Quality
▪ In precision engineering company needs to make sure that the
quality is always high and that things are done right first time every
time.

Accuracy in measurement describes how closely the
measurement from your system matches the actual or true
measurement of the thing being measured.
Precision in measurement describes how well a
measurement system will return the same measure; that is its
Repeatability.

THE PRECISION ENGINEERING
FOCUSES ON MANY AREAS
Research
Design
Development
Manufacture and measurement of high accuracy components and
systems.

WHY PRECISION ENGINEERING?
 Improve Product Performance
 Accuracy
 Reliability
 Improved Life
 Safety
 Increase Manufacturability
▪ Automatic Assembly
 Lower Costs
▪ Circuit Integration
 Advance Science and Technology

Design and Production System
▪ Lifecycle Engineering, Product and Process Modeling, Design Theory,
CAD/CAM/CAE, Rapid prototyping , Automated & Intelligent System, and
Production Management
Precision Machining
▪ Cutting, Abrasive machining, injection molding and etc.
Mechatronics
▪ Micro machines, Intelligent robots, Information Instruments, Precision
positioning, Machine tool & tooling, Intelligent control, Mechanism & mechanical
elements, etc.

THE PRECISION ENGINEERING TOOLBOX
INCLUDES:
▪ Design Methodology
▪ Error budgeting
▪ Uncertainty analysis
▪ Metrology
▪ Calibration/error compensation
▪ Precision controls and actuators and sensor

THE PRECISION ENGINEERING TOOLBOX
Precision engineering is also a body of knowledge, wisdom, and techniques that
has been developed, tested, and proven over time to be able to achieve these
objectives.
Examples of these principles and techniques include:he deterministic
principlematic constraint
 The Deterministic Principle
 Kinematic Constraint
 Counter Principles

THE DETERMINISTIC PRINCIPLE
Machines and instruments obey cause-and-effect relationships. With enough
information about the system and the environment (and enough time and money in
the project plan), we can calculate the effects of various loads and effects and
compensate for them in the design and operation of the machine. This knowledge can
be applied in the form of error models; error budgets; and error mapping and
compensation.

KINEMATIC CONSTRAINTS
Precisely and repeatedly locating one rigid body relative to another
using no more than six points of contact, without inducing distortion
and allowing precision motion in the remaining (6 – N) degrees of
freedom.

COUNTER PRINCIPLES
A theoretically perfectly symmetrical, perfectly formed, perfectly rigid machine has an
elegance that one should not aspire to in engineering. All that perfection costs money.
Sometimes, the most cost-effective solution is to introduce imperfection. Given the
impossibility of achieving a perfectly formed, perfectly rigid machine, it may be better to
introduce a small amount of controlled compliance into a system, in such a way that it
will relieve stresses while minimally impacting performance.

PRECISION ENGINEERING - JOURNAL OF THE
INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND
NANOTECHNOLOGY
 Study and practice of high accuracy engineering, metrology, and manufacturing.
 The journal takes an integrated approach to all subjects related to research, design,
manufacture, performance validation, and application of high precision machines,
instruments, and components, including fundamental and applied research and
development in manufacturing processes, fabrication technology, and advanced
measurement science.
 The scope includes precision-engineered systems and supporting metrology over
the full range of length scales, from atom-based nanotechnology and advanced
lithographic technology to large-scale systems, including optical and radio
telescopes and macro metrology.

It includes the analysis and design of components as well as machines and
instruments.
The analysis of components includes modeling, simulation and prototype
behavior.
Elements of research are:
▪ structural loop components
▪ bearing behavior
▪ driving system
▪ guiding elements
▪ probing systems

Important research activities are:
 structural loop design including materials
 thermal loop design
 static behavior analysis (FEM)
 dynamic analysis and simulation of machine-elements and electro-mechanical servo system
 design and validation of precision machinery prototypes:
o single point diamond turning machines
o high precision measuring machines
o high precision probing systems

DETERMINISTIC DESIGN
Everything has a cost, and everything performs (to at least some
degree)
Successful projects keep a close watch on budgets (time, money,
performance)
Do not be shy about taking all the performance you can get for the
same cost!

DESIGN PROCESS
Follow a design process to develop an idea in steps from:
 First Step:
Evaluate the resources that are available
 Second Step:
Carefully study the problem and make sure you have a clear understanding of what needs to
be done and what are the constraints (rules, limits)
 Third Step:
Start by creating possible strategies using words, analysis, and simple diagrams
 Fourth Step:
Create concepts to implement the best strategies, using words, analysis, and sketches

 Fifth Step:
Develop modules, using words, analysis, sketches, and solid models
 Sixth step:
Develop components, using words, detailed analysis, sketches, and solid models
 Seventh Step:
Detailed engineering & manufacturing review
 Eighth Step:
Detailed drawings
 Ninth Step:
Build, test, modify...
 Tenth Step:
Fully document

TWO CONTENT LAYOUT WITH TABLE
▪ First bullet point here
▪ Second bullet point here
▪ Third bullet point here
Class Group 1 Group 2
Class 1 82 95
Class 2 76 88
Class 3 84 90

TWO CONTENT LAYOUT WITH
SMARTART
▪ First bullet point here
▪ Second bullet point here
▪ Third bullet point here
Task
Description
Step 3
Task
Description
Step 2
Task
Description
Step 1

Introduction to Precision Engineering

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