8.  APPLICATION OF THE COMPUTER SYSTEM IN DESIGN ENGINEERING

    The  following  shows  the  possible  areas  where computer systems can
    perform design engineering.

    1) Storage and Retrieval of Design Data

    Manual storage and retrieval of design data are very time consuming and
    ineffective.   Data is generally scattered in books, drawings, letters,
    notes, catalogues, standards, data sheets, contracts, surveys,  reports
    and  on  microfilms.   Few designers can cope with such a heterogeneous
    collection.  The usual practice is therefore to limit the range of data
    sources that are consulted, which in turn may lead to the uniformity of
    products and to the neglect of  new  effective  components,  materials,
    methods, processes or tools.

    It  is  technically feasible to increase considerably the effectiveness
    of this activity by storing all design data in a computer database  and
    providing  a  fast  access  to every item whenever required, and in the
    format which is the most suitable for the situation at hand.

    2) Generation of Tentative Design Solutions

    Traditionally tentative  solutions  to  critical  design  problems  are
    created  by  senior designers and are described as they are created, on
    sheets of  paper  using  the  language  of  sketches,  rough  diagrams,
    mathematical expressions and short explanatory notes.

    These   outlines   of   solutions,   accompanied   by  generous  verbal
    explanations and elaborations are then  translated  by  draughtsmen  or
    technicians  into  formal  drawings, full diagrams, product description
    sheets, prototypes etc.  For less critical areas the  two-stage  design
    process is not normally necessary.

    The  creation  of solutions and the preliminary evaluations follow each
    other in a rapid succession throughout this creative design stage.  The
    process  seems  to be so efficient and ergonomically well-adjusted that
    some researchers deny any possibility of its  improvement.   This  view
    however, is not correct.  Many improvements are possible, including the
    following:-

    a) The quality of the visual feedback to designers may be  considerably
    improved by the use of interactive colour graphics terminals.

    b)  Modern  man-machine interfaces offer rapid editing facilities which
    designers may use for preliminary error elimination.

    c) Machines are very effective at rapid checking of tentative solutions
    for  mutual  compatibility  and  consistency.   This  further  improves
    preliminary error elimination.

    d) Voice input facilities offer the designer the possibility of  adding
    verbal comments to his output during the process of creation.

    e)  Half-baked  ideas  and exploratory thoughts may be entered into the
    machine and stored in the designer's private files in the the  form  of
    sketches, diagrams or comments for later browsing.

    f) Rapid retrieval and display of previous designs, relevant guidelines
    etc.  from the database may stimulate the designer when his inspiration
    is about to disappear.

    It  is  now  feasible to construct intelligent, knowledge-based systems
    which can help designers to use pattern recognition or heuristics as  a
    strategy  for  the  creation  of  complex,  tentative design solutions.
    These solutions can be evaluated later using conventional CAD programs.
    An advanced intelligent system is able to:-

    a) store design constraints and requirements;

    b)  elicit from an expert designer a large number of design rules based
    on his/her experience;

    c) apply these rules and requirements/constraints  to  a  given  design
    problem and to generate a set of tentative design solutions;

    d)  request  from  the  designer  additional  information  whenever the
    knowledge stored in the system proves to be inadequate;

    e) explain to the user which rules have been used and in  which  order,
    for the purpose of creating design solutions;

    f)  learn  from  its  experience  and  rearrange its own knowledge base
    accordingly.

    3) Evaluation

    The idea is to enter a tentative configuration, layout and/or shape  of
    a  future  product  into  a computer and then use its considerable data
    processing capabilities for the purposes of:-

    a) predicting various aspects of product performance by  simulation  or
    mathematical analysis;

    b) comparing the predicted and specified performances;

    c)  modifying  the  product  model  with a view to eliminating observed
    errors;

    d)  repeating  the  whole  cycle  until  all  aspects  of  the  product
    performance are satisfactory and

    e)  repeating  the  whole  cycle  with  radically  different  tentative
    solutions until the best solution emerges.

    4) Communication Links with Other Functions

    Design is only a constituent activity of a complex process of planning,
    marketing,  purchasing,  storing, manufacturing, testing, installation,
    maintenance of product.  The two major  tasks  of  computer  technology
    are:-

    a)  to  provide  aids  for collecting, storing, processing, retrieving,
    distributing and utilising  information  needed  for  each  constituent
    activity of this process;

    b)  to  provide  the means for communication of information between the
    various constituent activities.

    9.  BENEFITS THAT CAN BE OBTAINED FROM A CAPM SYSTEM

    In view of the high competition for good quality and reliability  of  a
    product,  a  company  is  usually willing to invest in CAPM to help its
    business.  However, selection of a cost-effective system  is  not  easy
    and  the  benefits  which  can  be obtained are usually transparent and
    vague.  Below is a list to show some of the  possible  benefits  to  be
    gained from such a system:-

    1) Completion of orders on time;

    2) Ability to quote and maintain competitive delivery date;

    3)  Reduction  in  the level of working capital tied up in stock levels
    and work-in-progress;

    4) Maintaining high plant utilisation;

    5) Reduction of investment in capital equipment by more effective  work
    loading;

    6) Increasing profitability;

    7) Providing data for strategic planning;

    8) Reducing the amount of paperwork;

    9) Improving reliability and quality;

    10) Improving documentation;

    11) Improving communication between departments and personnel;

    12) High standards of design;

    13) Having more control on the production line, with minimum cost.

    10.  GENERAL POINTS OF VIEW FOR PLANNING A SYSTEM

    There  are  over  80  computer  manufacturing  companies and over 4,000
    software packages in the U.K.  It seems  difficult  for  a  company  to
    choose  suitable  hardware  and  software systems to implement CAPM.  A
    vague notion that computerisation should be beneficial  is  not  enough
    and   patient   research  into  available  systems,  undertaken  before
    investment is important.  Following are some opinions about designing a
    computer system and buying it.

    While  designing  computer  systems,  the  items  noted below should be
    considered carefully.

    1) Data management functions and data processing procedures  should  be
    as well-specified and as simple as possible.

    2)  Complicated calculations and data manipulation procedures should be
    cost-effective, pragmatic and straightforward.

    3) The basic principle to follow while designing a system should be  to
    divide  the overall, major system to be designed into smaller, feasible
    issues by identifying and specifying them as different  entities.   The
    next  step  is  to  design  a  solution  to  the  issues identified and
    implement them after joining them together  into  a  coherent,  logical
    sequence.   The results can then be output to terminal displays or onto
    paper.  Attention should be paid to the scheduling necessary to produce
    such output on a timely basis.

    4)  In  the  various manufacturing, servicing, operating functions, the
    processing patterns which are  related  to  each  other  should  be  so
    integrated  as  to  enable  them  to  interface  with  each other.  The
    interfacing of different but related computer systems will be more  and
    more in demand in the future.

    5)  The  systems  should be designed so that they degrade gradually and
    recover promptly.  Gradual degradation capabilities  enable  the  large
    computer  complexes  to  share  the load.  Prompt recovery capabilities
    promote the availability of the system.

    While buying the computer hardware and software,  the  following  items
    should be carefully evaluated:-

    1) While choosing the computer hardware,  the  items  to  be  seriously
    considered are:-

    a) its CPU speed;

    b) its compatibility with existing computer equipment;

    c) its reliability;

    d) the peripheral or allied equipment required.

    2) The prices of the hardware/software cannot be ignored.  The study of
    prices should include one time cost, ongoing and hidden costs, not only
    for  the  mere hardware but also for the necessary software, peripheral
    equipment, materials, supplies and the  maintenance  services  offered.
    The  prices  of  the  physical  environment  necessary  and the desired
    security features should also be taken into account.

    3)  While  evaluating  the  software  produced   by   the   vendor   or
    manufacturer,  reference  should  be  made  as  to  how  many  customer
    engineers, program analysts,  systems  engineers  and  other  technical
    persons  the  vendor  not  only  employs  but is also committed to make
    available from time to time for various purposes, such as installation,
    maintenance and support.

    4) While choosing the software, a study should be made as to:-

    a) how well the software functions;

    b) whether it is flexible enough to permit changes and updates that may
    be needed in the future;

    c)  whether  the  software  package  has  experienced  any  outstanding
    problems;   -  such information may be gathered from the vendor and the
    various users or user groups who  have  experience  with  the  software
    package in question.

    5)  While selecting the computer hardware and software it is worthwhile
    realising that very large investments were required in the past for not
    only  the computer on-line systems but also the batch systems.  So many
    organisations could not afford  such  trouble  and  expense.   However,
    recent  years have seen a gradual decline in such expenses required for
    both computer  hardware  and  software,  for  both  batch  and  on-line
    systems.   This  has  resulted  in  an  environment where more and more
    organisations are willing and able to make  the  necessary  investments
    not only for batch processing systems but also for on-line and realtime
    systems.  The recent explosion in the use of smaller computers mini and
    microcomputers,  has  added  to the stimulus.  However, there are still
    many small organisations which may not  be  able  to  develop  in-house
    software systems.

    As  mentioned in the previous sections a conceptional automated factory
    is an integrated four tier structure,  however  it  is  not  absolutely
    necessary  to  do all the re-organising work at the same time.  Usually
    the work is started  at  linking  the  existing,  stand-alone  personal
    computers together and employing more multiuser computers.

    The   next   section   will   concentrate  mainly  on  the  end  user's
    microcomputer.

    11.  SELECTION PROCEDURE FOR AN END USER'S MICROCOMPUTER SYSTEM

    Although  the  details  for  different  applications  will  vary,   the
    selection  process  can,  in  effect,  be  broken  down into just a few
    decisions.  In terms of hardware, the choice lies between  8-,  16-  or
    32-bit systems.  It has already been noted that the 8-bit system, while
    often considered obsolete, has years of useful life  remaining  in  the
    right  situation.  If considerable expansion of the system is envisaged
    however, or if the workload involves  large  numbers  of  transactions,
    then a 16- or 32-bit machine will probably be the better choice.

    The  second  major  hardware  parameter  to  be determined concerns the
    method and amount of mass storage.  The standard floppy disk,  even  in
    its  most  advanced  form,  offers  only around 1 Mbyte of store.  If a
    large inventory of stock, for example, has to be recorded, this  figure
    can  soon be exceeded.  Of course, work can be broken down into smaller
    parcels, but the result can be seemingly endless changes of disk.   The
    alternative, the Winchester disk offers capacities of back-up store for
    archive purposes when needed.

    The final key hardware choice  concerns  the  printer.   The  essential
    choice  here lies between a relatively low-cost matrix printer offering
    reasonable speed but limited quality, and a daisy wheel  printer  which
    offers high quality at a speed which is directly related to price.  The
    decision  will  depend  on  the  use  made  of  any  printout.    Where
    correspondence quality is required, there will be no alternative to the
    daisy wheel.  In many cases, the  near-letter  quality  of  the  better
    matrix printer will prove adequate.

    The  hardware  will  largely  condition the choice of operating system.
    Usually an 8-bit system implies that the operating system will be  CP/M
    (although  Apple, Tandy and Commodore have their own operating systems,
    CP/M is available as an extra on a special hardware card).  CP/M offers
    the  advantage  of  a  large, existing library of application software.
    There are also 16-bit versions of CP/M but in this case the most likely
    choice  will  be MS/DOS.  Ready made application of software for MS/DOS
    is still limited, although increasing rapidly.

    One last option is  Unix.   This  is  currently  the  most  fashionable
    operating  system  among computer experts and is being widely promoted.
    However it is not necessarily the most suitable system for the newcomer
    to computing and a significant body of opinion in the US (including IDC
    analysts) does not expect it to become the dominant system.   Unix  has
    clear  advantages,  in  terms  of  its portability between machines and
    certain more sophisticated features, but it is far from  user-friendly.
    It is best suited to large microcomputer installations.

    12.  END USER'S MICROCOMPUTER

    In  hardware  terms,  a  modern  computer  can serve a great variety of
    purposes.  The same combination of processor,  memory,  control  cards,
    keyboard  and  display  can  be  an intelligent terminal, a stand-alone
    computer,  an  enquiry  station  a  word  processor  or  a   management
    workstation.   It  could  even  be all of them or any mix of them.  Any
    computing device is, to a large extent, what the user wants  it  to  be
    and  its  application is largely determined by the controlling software
    and associated equipment.

    The  present  microcomputer  generation  can  be  summarised  in  three
    categories,

    1)  Single  board  computer:  this kind of computer is derived from the
    intelligent terminal and is largely used for  shop-floor  applications.
    The  existing problem is to integrate different bus systems such as IBM
    PC bus, STD bus,  Multi-bus  and  VME  bus.   However,  some  interface
    systems  have  been  developed to connect them together.  For instance,
    the IEEE488 bus has allowed PCs  and  PC-  compatibles  to  perform  as
    measurement  system  workstations.  The chief advantage of this type of
    machine is its flexibility for future expansion of  a  production  line
    since other peripheral equipment can be added if necessary.

    2)  Single User Computer:  this type of computer is usually standalone,
    providing support for a range  of  executive  activities:-  information
    handling,   data   retrieval,   display,   access  to  remote  computer
    facilities, 'what if' solutions and some clerical tasks.   At  present,
    most  of these machines have added more facilities such as, 'window and
    mouse', so that their activity can  be  extended  to  communicate  with
    other PCs and thus serve more people by sharing the same database.

    A  wide  range  of  products can be found on the market.  However, IBM-
    compatibility  is  stressed  since  a  wide  range  of   software   and
    information are available.

    3)  Multi-user  computer:   this  type of machine can usually support 6
    users, but some supermicros can  even  support  up  to  32  users.   At
    present  as  far  as integration is concerned, there is an argument for
    either connecting PCs by networks or using a multi-user computer.   The
    latter  as  well  as being cheap for specific purposes such as computer
    aided design/  computer  aided  manufacturing,  is  also  suitable  for
    manipulating large scale data entry and large databases.

    13.    OPTIONS   OF   HARDWARE   FOR   MICROCOMPUTERS  AMONGST  VARIOUS
    MANUFACTURERS

    With up to 600 systems claimed to be suitable  for  business  use,  the
    microcomputer  purchaser  is  spoilt for choice.  However many of these
    systems and their manufacturers will not be around in a few years time.
    The  failure rate in the microcomputer industry is and will continue to
    be, high so the buying process  is  partly  a  matter  of  picking  the
    probable survivors.

    Micros are essentially very similar to each other, relying on a limited
    range of parts, the organisation of which determines  the  architecture
    of  the  system.   The  Z80  chip is used in the vast majority of 8-bit
    computers;  the Intel 8080 series is the most common 16-bit chip.  Even
    when  it  comes  to  packaging,  the  options are limited, so that most
    microcomputers tend to be nearly the same as makes no difference.  This
    is  particularly  true  of the machines of the mainframe manufacturers,
    which in many cases buy out their microcomputers and  package  them  to
    match the rest of their range.

    14.  SOFTWARE FOR CAPM MICROCOMPUTER SYSTEMS

    There  is  a  wide  range  of  CAPM  software  packages  available  for
    microcomputer systems.  However their prices are varied.  The  cost  of
    the  software  package  is  largely  dependent on the requirements of a
    factory.  Typically, a system may consist  of  the  following  software
    packages:-

    1) Work-in-progress - #680 to #800

    2) Scheduling - #400 to #800

    3) Shop documentation - #350 to #975

    4) Job costing - #150 to #2500

    5) Material list - #150 to #400

    6) Stock control - #295 to #800

    7) Bill of material - #200 to #1000

    8) Material requirements planning - #300 to #600

    9) Purchase order processing - #300 to #800

    10) Sales order processing - #200 to #800


    CONCLUSION

    The  integrated  CAPM system for an automated manufacturing company has
    been discussed.  It  is  a  four-tier  structure:-  workstation  level,
    supervisory  level, planning processing level and corporate information
    processing level.  The functional areas of each tier and between  tiers
    are  linked  together  to  achieve  a  complete integration.  Computing
    systems to complement the CAPM systems are basically the  mainframe  or
    minicomputer  as  a  control  database  console  and  the microcomputer
    networks systems as the end user's fingertip  intelligent  workstation.
    Since  the  end  user's  micro  system  is usually a starting point for
    re-organising the current system, more details about it have  been  put
    into the report.

    It  was  found  that  there  were  plenty  of  computing  manufacturing
    companies.   Their  products   were   mainly   divisible   into   three
    categories:-   single   board   computers,  single-user  computers  and
    multiuser computers.  The start-up costs for a small micro  system  and
    medium system are around #5450 and #30,875 respectively.

    Other  topics  included  in  the  report  were  'What is CAPM?' and the
    background for the boom of CAPM.

    Although a  list  of  benefits  has  been  included,  it  seems  to  be
    insufficient  and should contain more potential benefits that computers
    can contribute.

    As a conclusion, the focal points of a computer system which implements
    CAPM  are cost-effectiveness and the need of a manufacturing company to
    allow for both short and long-term expansion.