\chapter{Embodiment Design}
In the previous two chapters different devices that perform the requirement were
derived by using the morphological chart idea.  The concepts are sketched not
in great detail but in a way that present the major functions that compose the
device. These concepts were then
evaluated based on three different stages.  The first stage was to subject the
concepts to the specification table, if it pass the demands then a feasibility
test is conducted.  If the concept passes the first two stages then it will be
subjected to relative evaluation based on the Pugh method.  
In this stage of the design process the design team starts what could be called
 the embodiment design stage.  The word embody means to to give something a
 a tangible expression.  This chapter
discusses the presentation of the concept (s) that pass the evaluation criteria. 
The idea of presenting the information by drawing was introduced when different
concepts were generated from the morphological chart.  The sketches to present
the concepts are not detailed they are enough to demonstrate the combination of
the different function mechanisms that produce the concept.  The figure down
shows four conceptual sketches of a device that removes leaves from lawns.


\begin{figure}[h]
\vspace{5in}
\caption{Conceptual Sketches}
\end{figure}
 

It should be reemphasized that the design process is an iterative process, which
means that if additional refinements were found necessary after the skeleton
sketches or while in the evaluation stage
 the designer should iterate back to the concept phase and possibly generate new
 concepts. The drawback of this process it takes time, but that should be
 implanted in the scheduling of events.
 
 In the word of engineers information need to be passed by drawings.  Analysis,
 manufacturing and assembly of the product is based on drawings.  The following
 section discusses the type of drawings that are required by the designing
 team.


\section{Product Drawings}
In the design process drawings may be used to serve the following objectives 
\begin{enumerate}
\item Drawings are the proffered form of data communications in the world of
engineers.  
\item Drawings are used to communicate ideas between the designers and between designers and
manufacturing personnel 
\item Drawings simulate the operation the product
\item Drawings are used to check for the completeness of the product
\end{enumerate}


There different types of drawings that can be used at different levels, these
are
\begin{enumerate}
\item {\bf Sketches (Layout Drawing):}Sketches are generated during the conceptualization stage of the design process.
Different mechanisms of each function or sub-function are first sketched.  These
sketches are then used to build devices. 
 These sketches are serves the purpose of presenting the completeness of the
 device. These sketches are a working document that
supports the development of the major components and their relations.  
They are made to scale, but only the important dimensions are shown in the
layout.  Tolerances are usually not shown unless they are critical.  This form
of drawing is needed in the analysis.  When an individual component is analyzed
a sketch that present the relation of this part with it surrounding is often
called Free Body Diagram {\bf FBD}.
\item {\bf Detail Drawings:}  As the product evolves a detail of individual
components develop.  A typical detail drawing is shown in the figure
\ref{detail}
\begin{figure}[h]
\vspace{6in}
\caption{Typical Detail Drawing}
\label{detail}
\end{figure}
The important characteristics of a detail drawing includes
\begin{enumerate}
\item All dimensions must be tolerances
\item Materials and manufacturing detail must be clear and in specific language
\end{enumerate}
These drawings are made using a CAD system such as ProE.   
\item {\bf Assembly Drawings:} The goal of the assembly drawing is to show how
components fit together.  Figure \ref{assem} shows a typical assembly drawing.An assembly drawing has the following characteristics
\begin{figure}[h]
\vspace{6in}
\caption{Typical Assembly Drawing}
\label{assem}
\end{figure}
\begin{enumerate}
\item Each component is identified with a number referenced to a list of all
components
\item Necessary detailed views are included to explain information that is not
clear in other views

\end{enumerate}

\end{enumerate}

\section{Bill of Material}
The bill of material is an index of the parts were used in the product.  A
typical bill of material is shown in Table below.  
\begin{figure}[h]
\vspace{2in}

\end{figure}
The following 
information should be on a bill of material
\begin{enumerate}
\item The item number: This is a key to the components on the assembly drawing
\item The part number:  This is a number used throughout the purchasing,
manufacturing and assembly system to identify the component.  The item number
is a specific index to the assembly drawing, the part number is an index to the
company system.
\item The quantity needed in the assembly
\item The name and description of the component
\item The material from which the component is made
\item The source of the component
\item The cost of the individual component.  This part will be kept for the
design team. 
\end{enumerate}

\section{Prototype}
  
The experiment phase of the engineering design  requires transofrmation of the paper
drwaings into hardware constructed and tested to verfiy the concept workability.

There are three construction techniques that are available for the designers, namely
\begin{enumerate}
\item {\bf Mock-up}: is generally constructed to scale from plastics, wood,
cardboard and so forth to give the designer a feel for his design.  It is often used
to check the clearance, assembly techniques, manufacturing consideration and
apperance.  This is the least expensive technique, realtively easy to produce 
 and can be used as a tool in
selling the idea to clients or manegement.  A solid models in CAD system can often
replace the moke-up.  Moke-ups are usually refered to as a proof of concept
prototype.

\item {\bf Model} : which relates the
physical behavior of the system through mathematical similitudes.   The modeling is
usually refered to proof of product prototype. There are
different
types of models used to predict behavior of  a real system
\begin{enumerate}
\item {\bf True} is an exact gemoetric reproduction of the real system, built to
scale and satisfy all retrections imposed by the design parameters
\item {\bf Adequate} construted to test specific characteristics of the design and
is not intended to yield information concerning the total design
\item {bf Distorted} Purposly violates one or more design conditions.  This
violation is foten required when it is difficult or impossible to satisfy the
specific conditions due to time, material or physical  characteristics and it is
felt that reliable information can be obtained through the distrotion.
\end{enumerate}
\item {\bf Prototype}: is the most expensive technique and the one producing the
greatest amount of usfeul information.  The prototype is constructed, full scale
working physical suystem.  The prototypes can be comprehensive or focused.  A
comprehensive prototype corresponds to a full scale, fully operational version of
the whole product. An example of the comprehensive prototype is the beta prototype given
to customers in order to identify any remaining design flaws beofre committing to
production.  In contrast to comprehensive prototypes, focused prototype coresspond
to one or few of the product elements.  Examples of focused prototypes include foam
models to explor different forms of a product. 
\end{enumerate}
  
