Chapter 1 Drawing office management and organization Every article used in our day-to-day lives will probably 7 Dimension figures have been produced as a result of solutions to a sequence 8 Relative importance of dimensions of operations and considerations, namely: 9 Indication of materials on drawings 10 Various degrees of finish 1 Conception 11 Screw threads 2 Design and analysis 12 Flats and squares 3 Manufacture 13 Tapers 4 Verification 14 Abbreviations for drawings. 5 Disposal. There were also five figures illustrating: The initial stage will commence when an original marketable idea is seen to have a possible course of 1 Method of projection development. The concept will probably be viewed 2 Types of line from an artistic and a technological perspective. 3 Views and sections The appearance and visual aspects of a product are 4 Screw threads very important in creating an acceptable good first 5 Tapers. impression. The technologist faces the problem of producing First angle projection was used for the illustrations a sound, practical, safe design, which complies with and the publication was printed on A5 sheets of paper. the initial specification and can be produced at an During the early days of the industrial revolution economical cost. manufacturers simply compared and copied component During every stage of development there are many dimensions to match those used on the prototype. progress records to be maintained and kept up to date However, with the introduction of quantity production so that reference to the complete history is available to where components were required to be made at different responsible employees. factory sites, measurement by more precise means was For many years various types of drawings, sketches essential. Individual manufacturers developed their own and paintings have been used to convey ideas and standard methods. Clearly, for the benefit of industry information. A good recognizable picture will often in general a National Standard was vital. Later the remove ambiguity when discussing a project and assist more comprehensive British Standard of Limits and in overcoming a possible language barrier. Fits was introduced. There are two clear aspects, which British Standards are listed in the British Standards are necessary to be considered in the specification of Catalogue and the earliest relevant Engineering component drawings: Standards date back to 1903. Standards were developed to establish suitable dimensions for a range of sizes of 1 The drawing shows the dimensions for the metal bars, sheets, nuts, bolts, flanges, etc. following component in three planes. Dimensions of the the Industrial Revolution and used by the Engineering manufactured component need to be verified because Industry. The first British Standard for Engineering some variation of size in each of the three planes Drawing Office Practice published in September 1927 (length, breadth and thickness) will be unavoidable. only contained 14 clauses as follows: The Designers contribution is to provide a Characteristics Specification, which in current jargon 1 Sizes of drawings and tracings, and widths of is defined as the ‘Design Intent Measurand’. tracing cloth and paper 2 The metrologist produces a ‘Characteristics 2 Position of drawing number, date and name Evaluation’ which is simply the Measured Value. 3 Indication of scale 4 Method of projection The drawing office is generally regarded as the heart 5 Types of line and writing of any manufacturing organization. Products, 6 Colour of lines components, ideas, layouts, or schemes which may be 2 Manual of Engineering Drawing presented by a designer in the form of rough freehand (e) quality control and inspection, sketches, may be developed stage by stage into working (f) updating, modification, and reissuing of drawings by the draughtsman. There is generally very drawings. little constructive work which can be done by other 2 Company standards Many drawing offices use departments within the firm without an approved their own standard methods which arise from drawing of some form being available. The drawing is satisfactory past experience of a particular product the universal means of communication. or process. Also, particular styles may be retained Drawings are made to an accepted standard, and in for easy identification, e.g. certain prestige cars this country, is BS 8888, containing normative and can be recognized easily since some individual informative references to international standards. These details, in principle, are common to all models. standards are acknowledged and accepted throughout 3 Standards for dimensioning Interchangeability and the world. quality are controlled by the application of practical The contents of the drawing are themselves, where limits, fits and geometrical tolerances. applicable, in agreement with separate standards relating 4 Material standards Physical and chemical to materials, dimensions, processes, etc. Larger properties and non-destructive testing methods must organizations employ standards engineers who ensure be borne in mind. Note must also be taken of that products conform to British and also international preferred sizes, stock sizes, and availability of rod, standards where necessary. Good design is often the bar, tube, plate, sheet, nuts, bolts, rivets, etc. and product of teamwork where detailed consideration is other bought-out items. given to the aesthetic, economic, ergonomic and 5 Draughting standards and codes of practice technical aspects of a given problem. It is therefore Drawings must conform to accepted standards, but necessary to impose the appropriate standards at the components are sometimes required which in design stage, since all manufacturing instructions addition must conform to certain local requirements originate from this point. or specific regulations, for example relating to safety A perfect drawing communicates an exact when operating in certain environments or requirement, or specification, which cannot be conditions. Assemblies may be required to be misinterpreted and which may form part of a legal flameproof, gastight, waterproof, or resistant to contract between supplier and user. corrosive attack, and detailed specifications from Engineering drawings can be produced to a good the user may be applicable. professional standard if the following points are 6 Standard parts are sometimes manufactured in observed: quantity by a company, and are used in several different assemblies. The use of standard parts (a) the types of lines used must be of uniform reduces an unnecessary variety of materials and thickness and density; basically similar components. (b) eliminate fancy printing, shading and associated 7 Standards for costs The draughtsman is often artistry; required to compare costs where different methods (c) include on the drawing only the information which of manufacture are available. A component could is required to ensure accurate clear com- possible be made by forging, by casting, or by munication; fabricating and welding, and a decision as to which (d) use only standard symbols and abbreviations; method to use must be made. The draughtsman (e) ensure that the drawing is correctly dimensioned must obviously be well aware of the manufacturing (adequately but not over-dimensioned) with no facilities and capacity offered by his own company, unnecessary details. the costs involved when different techniques of Remember that care and consideration given to small production are employed, and also an idea of the details make a big contribution towards perfection, likely costs when work is sub-contracted to specialist but that perfection itself is no small thing. An accurate, manufacturers, since this alternative often proves well delineated engineering drawing can give the an economic proposition. draughtsman responsible considerable pride and job 8 Data sheets Tables of sizes, performance graphs, satisfaction. and conversion charts are of considerable assistance The field of activity of the draughtsman may involve to the design draughtsman. the use, or an appreciation, of the following topics. Figure 1.1 shows the main sources of work flowing 1 Company communications Most companies have into a typical industrial drawing office. The drawing their own systems which have been developed over office provides a service to each of these sources of a period of time for the following: supply, and the work involved can be classified as (a) internal paperwork, follows. (b) numbering of drawings and contracts, (c) coding of parts and assemblies, 1 Engineering The engineering departments are (d) production planning for component manufac- engaged on ture, (a) current production; Drawing office management and organization 3 (f) drawings resulting from value analysis and Engineering works’ suggestions. Figure 1.2 shows the organization in a typical drawing office. The function of the chief draughtsman is to take overall control of the services provided by the office. The chief draughtsman receives all work coming Drawing into the drawing office, which he examines and Sales Service office distributes to the appropriate section leader. The section leader is responsible for a team of draughtsmen of various grades. When work is completed, the section leader then passes the drawings to the checking section. The standards section scrutinizes the drawings to ensure that the appropriate standards have been incorporated. Manufacturing All schedules, equipment lists and routine clerical work units is normally performed by technical clerks. Completed work for approval by the chief draughtsman is returned Fig. 1.1 via the section leader. Since drawings may be produced manually, or by electronic methods, suitable storage, retrieval and (b) development; duplication arrangements are necessary. Systems in (c) research; common use include: (d) manufacturing techniques, which may include a study of metallurgy, heat-treatment, strength (a) filing by hand into cabinets the original master of materials and manufacturing processes: drawings, in numerical order, for individual (e) advanced project planning; components or contracts; (f) field testing of products. (b) microfilming and the production of microfiche; 2 Sales This department covers all aspects of (c) computer storage. marketing existing products and market research for future products. The drawing office may receive The preservation and security of original documents is work in connection with of paramount importance in industry. It is not normal (a) general arrangement and outline drawings for prospective customers; Chief (b) illustrations, charts and graphs for technical draughtsman publications; (c) modifications to production units to suit customers’ particular requirements; (d) application and installation diagrams; (e) feasibility investigations. Section leaders 3 Service The service department provides a reliable, prompt and efficient after-sales service to the Technical customer. The drawing office receives work Designers clerks Finished drawings associated with (a) maintenance tools and equipment; Senior Standards (b) service kits for overhauls; draughtsmen section (c) modifications to production parts resulting from field experience; Draughtsmen Checkers (d) service manuals. 4 Manufacturing units Briefly, these cover all departments involved in producing the finished end- Trainees product. The drawing office must supply charts, drawings, schedules, etc. as follows: (a) working drawings of all the company’s Drawing office library products; (b) drawings of jigs and fixtures associated with Reprographic section manufacture; (c) plant-layout and maintenance drawings; (d) modification drawings required to aid Manufacturing units Sales Service Development production; (e) reissued drawings for updated equipment; Fig. 1.2 4 Manual of Engineering Drawing practice to permit originals to leave the drawing office. perform a much more effective role in the design process A drawing may take a draughtsman several weeks to and many examples of its ability follow—but it will develop and complete and therefore has considerable not do the work on its own. The input by the value. The reprographic staff will distribute copies which draughtsman needs to follow the same standards applied are relatively inexpensive for further planning, in the manual method and this fact is often not production and other uses. A library section will understood by managers hoping to purchase CAD and maintain and operate whatever archive arrangements obtain immediate answers to design enquiries. The are in operation. A large amount of drawing office draughtsman needs the same technical appreciation as work comes from continuous product development and before plus additional computing skills to use the varied modification so easy access to past designs and rapid software programs which can be purchased. information retrieval is essential. To introduce CAD an organization must set out clear objectives which are appropriate to their present and future requirements and Fig. 1.3 includes aspects of Engineering drawing policy which could appear in such plans. The following need consideration: practices (a) CAD management roles; The comments so far refer to drawing offices in general (b) creation, training and maintenance of capable and typical organizational arrangements which are likely CAD operators; to be found within the engineering industry. Good (c) CAD awareness of design project team members communication by the use of drawings of quality relies in addition to their leaders; on ensuring that they conform to established standards. (d) the flow of work through the system and the BS 5070, Parts 1, 3 and 4 dealing with engineering selecting of suitable types of project; diagram drawing practice, is a companion standard to (e) associated documentation; BS 8888 and caters for the same industries; it provides (f) possible changes to production methods; recommendations on a wide variety of engineering (g) needs involving the customer; diagrams. Commonly, as a diagram can be called a (h) system needs relating to planning, security and ‘drawing’ and a drawing can be called a ‘diagram’, it upgrading; is useful to summarize the difference in the scopes of (i) CAD library and database (Storage of drawings, these standards. BS 8888 covers what are commonly symbols, etc.) and archive procedures. accepted to be drawings that define shape, size and form. BS 5070 Parts 1, 3 and 4 covers diagrams that Many similar aspects will be appropriate in particular are normally associated with flow of some sort, and applications but good intentions are not sufficient. It is which relate components (usually indicated by symbols) necessary to quantify objectives and provide dates, functionally one to another by the use of lines, but do deadlines, numbers, individual responsibilities and not depict their shape, size or form; neither may they budgets which are achievable if people are to be in general indicate actual connections or locations. stretched and given incentive after full consultation. Therefore, any drawing or diagram, whether Present lines of communication will probably need to produced manually or on computer aided draughting be modified to accommodate CAD, and planning equipment, must conform to established standards and integration is vital. A possible approach here is the will then be of a satisfactory quality for commercial appointment of a CAD Director with the ultimate understanding, use and transmission by electronic and responsibility for CAD technology assisted by a Systems microfilming techniques. All of the examples which Manager and an Applications Manager. follow conform to the appropriate standards. Feedback Drawing practice and the Company application. computer (CAD: Computer Design, manufactu- ring, sales and service aided draughting and Company Organization Implementation and communication design) computer strategy and policy for 5 year term and methods systems for all users Hardware The computer has made a far bigger impact on drawing office practices than just being able to mimic the Software traditional manual drawing board and tee square Performance technique. However, it depends on drawing office monitoring Resources requirements and if only single, small, two dimensional and control drawings and sketches are occasionally required, then there may be no need for change. CAD can however Fig. 1.3 General computer policy relationships Drawing office management and organization 5 A CAD Director has the task of setting and however, demanded more specific and precise implementing objectives and needs to be in a position specifications. to define binding policy and direct financial resources. A national form of draughting presentation was He will monitor progress. A Systems Manager has the needed to promote a common understanding of the role of managing the computer hardware, the software objectives and in September 1927, BS 308 came to and the associated data. Company records and designs fruition, as the recognized National Code of Practice are its most valuable asset. All aspects of security are for Engineering Drawing. the responsibility of the Systems Manager. Security The initial issue was A5-size and contained only 14 details are dealt with in the next chapter. The clauses. Dimensioning was covered in four paragraphs Applications Manager is responsible for day to day and tolerancing in only one. The recommendations operations on the CAD system and the steady flow of were based on just two example drawings. The recom- work through the equipment. He will probably organize mended projection was first angle. training for operators in the necessary computer skills. Both of these managers need to liaise with the design Revisions project leaders to provide and maintain a draughting facility which is capable of increasing productivity to The life span of BS 308 was 73 years and five revisions a considerable degree. were made. The first in December 1943, followed by Figure 1.4 shows the probable position of the CAD others in 1953, 1964, 1972 and 1985. The 1972 revision Director in the management structure. His department was a major one, with the introduction of three separate will be providers of computer services to all other parts replacing the single document: computer users within the company. The fifth (1985) revision replaced the Imperial Managing Director standard with a Metric edition. BS 308 was finally withdrawn and replaced by BS 8888 in 2000. The revisions were necessary to keep Manufacturing Chief Finance CAD abreast of technological innovations. Manager Engineer Manager Director As manufactured products became more sophisticated Chief and complex, the progress and development of Draughtsman Applications Systems manufacturing and verification techniques accelerated. Manager Manager Advances in the electronics industry ensured more applications in manufacturing with a very high degree Fig. 1.4 of sophistication. Much progress was also made since that single paragraph in the original 1927 version relating to tolerancing, together with the four paragraphs Why introduce BS 8888 and the two examples covering dimensioning. Geo- and withdraw BS 308? metrical tolerancing was not referred to at all in early versions. The subject gained prominence during the 1960s, especially when it was realized that a symbolic For 73 years, BS 308 was a highly regarded drawing characterization would assist in the understanding of office practice document. Why the change and what the subject by users and replace the use of lengthy was behind the decision to withdraw BS 308 and replace notes relating to geometric controls. it with BS 8888? This activity was addressed by the major revision in 1972 with the publication of Part 3, devoted entirely A drawing standard to the dimensioning of geometric tolerancing. From time immemorial, drawings have been the medium used to convey ideas and intentions. Hence the adage The replacement of BS 308 that ‘a picture is worth a thousand words’. No need for language, the picture tells it all. In recent years there Formerly, the Chief Designer and the drawing office has, unfortunately, developed another opinion since set, and were responsible for, company manufacturing CAD appeared on the scene, that there is no need for standards and procedures, for other disciples to follow. a draughtsman now as the computer does it all. The This practice gradually eroded away because of the truth of the matter is that the computer is able to extend advancement of progressive and sophisticated the range of work undertaken by the draughtsman and techniques in the manufacturing and verification fields. is really a very willing slave. The evolution of the Increasing commercial pressure for Design for Industrial Revolution required the ‘pictures’ to be more Manufacture and Design for Inspection, created the detailed. In the pre-mass-production era, manufacture demand for equal status. During the period separate was based on ‘matched fits’, with the assistance of standards were gradually developed for design, verbal communication. The advent of mass production manufacture and measurement. Each discipline utilized 6 Manual of Engineering Drawing similar terms but often with slightly different Basic differences interpretations despite their apparent commonality. The fundamental differences between BS 308 and BS An urgent need to harmonize the meaning of these 8888 are: terms was recognized by ISO. An international meeting in 1989 formed a Joint Harmonization Group. • The title: Technical product documentation (TPD) The Danish Standards Association funded a project Specification for defining, specifying and graphically to bring all design, measurement, and metrology representing products. standards together using definitions common to all, • Confirmation of the conventional use of the comma but with appendices for each discipline. as the decimal marker. A full ISO committee (ISO/TC 213) was formed, • BS 308 was a Code of Practice, a guidance document. with the Danish being responsible for the secretariat. BS 8888 is essentially an applications specification, The task allocated to this very vibrant committee providing a route map to 106 ISO standards. The progressed considerably, with many new international operative word is ‘specification’. BS 8888 carried standards being published. forward and contains a significant number of valuable A major happening that would affect the future of clauses contained in BS 308, which, at present, is BS 308 was the UK’s agreement in 1993 with the not in any ISO documentation. European Standards Authority (CEN), whereby BSI • BS 8888 is capable of accommodating significant would withdraw standards relating to technical drawing technical changes, known to be in development, plus in favour of the implemented ISO standards covering the facility to accommodate future additions and the same subject. Initially, BSI systematically withdrew changes. various clauses of BS 308 as the relevant ISO Standards • With 106 related ISO standards, BS 8888 has a were introduced. much broader field of application than its predecessor PD 308 was introduced in June 1996 as a guidance and its 30 related ISO standards. document to assist the transition from BS 308 to the • BS 8888 provides common understanding, and implementation of ISO drawing standards. In 1999, as acceptance between the designer and the metrologist was the case in 1927, major decisions were deemed of ‘uncertainty’. These are caused by differences necessary, and the following were made: between the Design Intent Measurand (Char- acteristics Specification) and the Measured Value • To transfer the United Kingdom totally to the ISO (Characteristics Evaluation) of the actual Standards base. manufactured part. • To prepare an applications standard to serve as both • BS 8888 is a uniform source of reference and will a specification for specifying and graphically be regularly updated to keep abreast of developments representing products, and as a route map to the as new international standards are finalized and ISO Standards. implemented. • To withdraw BS 308. • It will capture any fundamental changes and will From this positive commitment, BS 8888 was created reflect moves towards an integrated system for and published on 15 August 2000. definition, manufacture and verification. The complete comprehensive title of BS 8888 is: • BS 8888 links each standard to the appropriate stage of the design process and lays the foundations for BS 8888. Technical product documentation (TPD). future development. Specification for defining, specifying and graphically representing products. BS 8888 will be revised every two years.
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