Sykes, Richard

English

Loughborough University Library: Open Journals

IT IN D&TWith pneumatics playing an increasinglyimportant role in industry, and the design andtechnology curriculum in process of revision,now is a good time to re-examine the place ofpneumatics in design and technology.Pneumatics has been rather a shadowypresence in the design and technologycurriculum documents published over the lastfour years, its inclusion or lack of it beingsomething of an indicator of each document'scommitment to control technology. Theoriginal order makes only a passing referenceto pupils knowing that mechanisms can beincorporated within pneumatic systems,whereas the proposals published in December1992 (the fold-out) at the height of the BluePeter technology debate go so far as to specifythat pupils be taught the use of a detailed list ofpneumatic components.So what really is the place of pneumatics indesign and technology? This article sets out toexplore this issue by looking at threeinterlinked areas: the place of pneumatics incontrol technology in the world outside school,the current use of pneumatics in schools inKS3 and KS4, and, to begin with, the part ithas played in the development of the subject ofdesign and technology.New LightonPneumaticsTechnical Writer,Economatics (Education) LtdSmall-scale industrial pneumatics integrate easily with construction kits likeFischertechnik for prototyping project ideas; they operate at safe lowpressures, suitable for the classroom• Control TechnologyA significant factor in the development fromcraft subjects into CDT was the SchoolsCouncil Project Technology scheme which waspublished in the Control Technology books in1974. It is interesting now to see how this firstattempt to frame a whole field of scientific andengineering activity into a school subject, dealtwith pneumatics. Alongside sections onstructures and electronics was a central sectionon the control of movement: electricalswitching to control the source of rotarymovement - an electric motor, and valves tocontrol the source of linear movement - apneumatic cylinder. Both were presented asbeing of equal importance.The growth of control technology led to asecond Schools Council project, ModularCourses in Technology, in the early eighties.This created the model of GCSE technology asa general core with a choice of specialistmodules. In this rather fragmented approach,pupils experienced pneumatics only if it wasone of the modules chosen by their school. It isworth comparing this model with a paralleldevelopment, the Scottish Standard GradeTechnological Studies syllabus, which haspneumatics as one of its core subjects; theothers being mechanisms, electronics andtechnology in manufacture with the emphasison integration of all four.Another interesting comparison is that betweenthe uncertain place of pneumatics in the ordersfor England and Wales, and the more positiveview taken in the equivalent order for NorthernIreland in which pupils both at KS3 and KS4are to be taught to use pneumatic cylinders andvalves in circuits to achieve desired effects. Itwould appear that curriculum developers inScotland and Northern Ireland have a vision oftechnology that embraces more of the nature ofcontrol technology as it exists outside schools.• The World Outside SchoolIn the world of control technology outsideschool, the design engineer has a choice ofthree basic types of actuator - electrical,pneumatic and hydraulic - to provide forceand movement. Each has its strengths andweaknesses and each is appropriate forparticular purposes. It is likely that all threewould be accompanied by an electronic controlsystem that is either hard wired orprogrammable.IT IN D&TThis animated head, madeas part of an NCET project incontrol technology, showshow pneumatics can beintegrated with computercontrol in a design and makeprojectOver the last ten years, major advances inpneumatics technology have meant that it isincreasingly favoured over electrical andhydraulic systems. New designs of valves andcylinders have brought greater efficiency;electronic control has increased accuracy andspeed of response; and miniaturisation hasmeant that a pneumatic system now occupies aquarter of the space it would have needed tenyears ago.The majority of automated manufacturingprocesses, especially in industries such asplastics, furniture, food and clothing makeextensive use of pneumatics because it is clean,safe, lightweight and cost-effective. Apneumatic system compares favourably withelectrical and hydraulic equivalents when itcomes to maintenance, durability and cost ofmanufacture. The automotive industry ismaking increasing use of pneumatics, not onlyin manufacturing processes, but in on-boardsystems such as suspension and centrallocking. The new clutchless car makes use of apneumatic gear selection system. In the fastdeveloping world of theme park thrill rides,pneumatic systems are used to fix safetyharnesses in place and to fire the passengervehicle at high speed into the looping ride.The growth of the pneumatics industry isindicated by the fact that in excess of £80m arenow spent annually on pneumatic componentsin the UK, compared with some £50m tenyears ago. In the same period, the hydraulicsindustry has suffered something like atwenty-five per cent reduction.• Classroom ExperienceTalking to teachers about their reasons forincluding pneumatics in their design andtechnology work, three ideas emerge:i) It has to be included if pupils are to begiven a complete and balanced experienceof control technology as it exists in theworld outside school.ii) It opens up the range of possible designand make projects for pupils, andgenerates new project ideas.iii) It makes an ideal vehicle for teachingideas about systems and control.In the words of one teacher: 'For me, systemsand control work should be built aroundpneumatics because of its immediacy andsimplicity, and the way it motivates pupils. Inhalf an hour they can learn something, use itand get a real sense of achievement'. This istrue across the full ability range. For theteacher, trouble-shooting is much simpler thanwith, say, electronics. There are fewerpossibilities for error, you can see what ishappening, and altering a circuit is simply amatter of reconnecting pipes to push fittings,rather than desoldering components.• School-Industry LinksOne of the purposes of school-industry links isto give pupils awareness and understanding ofindustry. Where this involves factory visitsteachers find that, for pupils who are familiarwith pneumatics, the array of modernmachinery is far less intimidating and oftenserves to stimulate project ideas such aspneumatically-operated pick and place devicesor systems for moving material on and offconveyors. Pneumatics is particularly useful inprojects that involve pupils' own small scalemanufacture. Chip making and can crushingfor recycling are popular projects; moreenterprising ones include printing tickets forIT IN D&TFig. 1:When compressed air isreleased into a cylinder, thepiston rod moves, providinglinear force and movementlocal events and manufacturing plastic beltsusing pneumatics to stamp holes and insertrivets for buckles.The use of pneumatics in the areas of leisureand animation is also reflected in schoolprojects. One pupil's advertisement for a tyrecompany featured an animated arm pumpingup an inflating tyre. At another school, a groupof pupils have produced an animated version ofthe Three Little Pigs complete withpneumatically-operated collapsing house and awolf who huffs and puffs by means of apneumatic cylinder.• KS3 Systems and ControlProjects such as these tend to be done in KS4,but pneumatics is also used extensively in KS3and is highly relevant to the latest draftproposals for design and technology in that itmakes tangible many of the key elements ofsystems and control specified at this level; i.e.pupils should be taught to use devices thatcontrol and transmit energy; to interconnectmechanisms to achieve different kinds ofmovement; to know that systems have inputs,processes and outputs; and to incorporatefeedback in their systems.The idea of a compressor as a device that usesa pump to compress air into a reservoir iseasily explained to any pupil who has everpumped up a bicycle tyre. The pneumaticcylinder is an eminently simple device fortransmitting energy (see Figure 1). Pressing thebutton on a control valve and seeing a pistonrod move as a result provides a clear practicaldemonstration of the concept of input andoutput. Once this is understood, theintroduction of another valve as a second inputclarifies the idea of AND and OR logicfunctions. Adding a flow restrictor to controlthe speed of the piston rod, or a reservoir togive a time delay provides further examples ofprocess. Alternatively, the input of a systemcould be the linear movement provided by acylinder, the process a series of linkages orother mechanisms, and the output a movementor number of movements on, for example, ananimated face.In pneumatic systems, the need for feedback inthe form of proof of position is easilyunderstood. In the system shown in Figure 2,cylinder A pushes a container under a hopperand cylinder B tips the hopper so that itscontents pour into the container. It is clearlyimportant that a feedback loop is built into thesystem so that cylinder B will not tip untilthere is proof that cy linder A has pushed thecontainer into position. Proof of position canbe achieved using just pneumatic components,but this kind of control of cylinders inconjunction with sensors provides a naturalprogression into integrating pneumatics withelectronic or computer control systems, whichis what schools tend to do in KS4.Fig. 2: The need for proof of positionfeedbackIT IN D&T• Equipping for PneumaticsEquipping to teach pneumatics need not beeither costly or complicated. A pneumaticsworkstation comprises a number of basiccomponents, a firm base to fix them to, and asource of compr~ssed air. As a beginning, thiscould be a small mobile compressor whichwould supply one or two workstations used forteacher demonstrating and practical work bygroups of pupils as part of a circus of systemsand control activities. Schools equipping forpneum~tics with whole classes would look toprovide five to ten workstations supplied by alarge fixed compressor with an airline installedaround the workshop, preferably inside servicetmnking alongside the low voltage electricitysupply. This obviously represents a substantialinvestment but has the advantage that, once setup, the resource lasts for years with noadditional cost other than the occasional coil ofpipe.Whatever the future of pneumatics in designand technology curriculum orders andsyllabuses, two points are clear. The increasingIK.S4lift.SOJiJJ~CORE • TEXTILESFOOD· GRAPHICSWith over 60 design assignments in eachpack, these are packed full of interestingcase studies. All are appropriate for the fullrange of post 14 courses including GCSETechnology, Design and Technology, GCSEspecialist extensions and GNVQ's. Mixedability and SEN supported.t6t1(iewu!loty~New from Old - Teach basic textile skillswith limited resources and time! It showspupils how to design make patterns,machine decorate and much more!TV Food - This pack encourages pupils tolook at foods around the world and uses themedia to bring recipes and cultures to life! Afun activity with technological potential.Pupil Planners . These planners areproduced in a lively, easy to fill in format toget pupils motivated about recording theirthoughts and decisions.number of teachers who use pneumatics find itto be an excellent way to teach systems andcontrol, and any coverage of modern controltechnology without it is simply incomplete.• ReferencesDENI, Curriculum (Programmes of Study andAttainment Target in Technology and Design)Order (Northern Ireland) 1992, HMSO, 1992Economatics,Airways: a Course in Pneumatics,Economatics,1994Fox, G. J. and Marshall D. E, ControlTechnology, Hodder and Stoughton, 1974NCC, Technology for Ages 5 to 16 (1992), NCC,1992NCC, Technology in the National Curriculum,HMSO,1990Patient, P. and Pickup, R., Modular Courses inTechnology -Pneumatics, Oliver and Boyd, 1983SCAA, Design and Technology in the NationalCurriculum Draft Proposals, SCAA, 1994Scottish Examination Board, Standard GradeArrangements in Technological Studies, SEB,1988"INNOVATIVE MATERIALS"Resource News, THERE, Spring 1994wrHtTOtK/-Food Technology at Work(available autumn '94)This new exciting pack uses the working characteristics andproperties of food for design. Each project has its own worksheetsenabling the busy teacher to teach food technology at its best.Sensory analysis, quality control and products and applications areall dealt with in a pupil and teacher friendly way.Designing with Food: SandwichesUsing the theme of Sandwiches pupils are introduced to foodproduct development. Pupils develop transferable D&T skills whilstthey: design with food, research to identify market opportunities,plan and carry out their production task and use sensory analysistechniques to test their ideas.SEND OFFICIAL ORDERICHEQUETO:Technopacks (ref:DA9), PO BOX 216,EPSOM, SURREY KT19 9YHAll packs are £14.95 each.Order 5 packs and choose another free!• FREE catalogue available·See us at the D&T Exhibition Stand H06

New Light on Pneumatics

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New Light on Pneumatics

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