Mechanical engineering topics

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1 Technická angličtina pro střední průmyslové školy se zaměřením na elektrotechniku a strojírenství Mechanical engineering topics reg. č. CZ.1.07/1.1.04/ str. 45 z 97

2 Materials used in engineering TALKING POINTS What materials do you know? What was the first material used by man? What material is used in aerospace industry? Name materials which you can find in a car. PRE-READING Exercise 1 Fill in the table below. MATERIAL OBJECT MATERIAL OBJECT wood stone steel aluminum copper glass gold iron rubber tyre, plastic Exercise 2 In the periodic table find the English equivalents to the Czech elements below. cín - zinek - železo - měď - hliník - uhlík - křemík - titan - READING MATERIALS USED IN ENGINEERING When you create something there are many different material types to choose from. In this article we will focus on material engineering. The materials used in engineering are grouped roughly into two categories: Metallic and Non-metallic. NON-METALLIC MATERIALS The remarkable nonmetallic materials are plastics, ceramics, corundum, etc. reg. č. CZ.1.07/1.1.04/ str. 46 z 97

3 METALLIC MATERIALS The most used metallic materials are steel and cast iron, aluminum and its alloys, copper and its alloy, tin, zinc, lead, wolfram, titanium. Metal is not only used for productions components but also for working and shaping of products. Furthermore, they are widely used as connecting material, making plating and as alloyed elements for steel. The best known materials in engineering are steel and cast iron. They are manufactured by mixing iron and carbon in a specific ratio. Steel contains carbon up to 2 % and cast iron more than 2%. Steel grades are classified by many standard organizations, based on the composition and the physical properties of the metal. Steel that contains less than 0,8% carbon is called hypoeutectoid and any steel with more than 0,8% carbon content is hypereutectoid. Higher carbon content increases hardness and strength and improves hardenability. The physical properties of steel include high strength, low weight, durability, flexibility, electrical conduction and corrosive and oxidation resistance. These properties of steel can be changed by adding certain alloys like chromium, nickel, manganese, molybdenum, wolfram and other elements. For example chromium can reduce corrosion resistance of steel and manganese soften the steel structure and thus increases the solidity. Properties of metal materials can be purposely influenced by heat treatment. Steel often requires heat treatment to obtain improved properties (e.g. increasing hardness or strength) or to neutralize negative effects resulting from previous manufacturing processes (e.g. removing internal stresses generated by fabrication processes). Heat treatment is the process of controlled heating and cooling of metals to alter their physical ad mechanical properties. There are various heat treatment Cast iron is an alloy of iron (more than 95% by weight) and other elements. The main alloying elements are carbon and silicon. Cast irons contain appreciable amounts of silicon, normally 0,3 to 4% and the amount of carbon in cast irons is 2.1 to 4%. Cast iron tends to be brittle, except for malleable cast irons. With its low melting point, good fluidity, castability, excellent machinability, resistance to deformation, and wear resistance, cast irons have become an engineering material. Cast irons which are used the most are grey cast iron and malleable cast iron. Aluminum, another significant material, is remarkable for its ability to reset corrosion, light weight and for the metal s low density. It is the most widely used non-ferrous metal. Structural components made from aluminum and its alloys are important especially in aerospace industry but also in other areas of transportation and building. Thanks to new methods of machining of aluminum alloys, steel constructions are replaced by aluminum alloys nowadays. However, aluminum alloy has to meet the requirements for solidity. The most popular aluminum alloy is duralumin because of its light weight and strength. reg. č. CZ.1.07/1.1.04/ str. 47 z 97

4 Another material used in engineering is copper. Copper is malleable and ductile metal and is a good conductor of both heat and electricity. It is used mostly for making of electrical cables and in building industry as sheet copper. Copper is too soft in comparison to steel, so it is often incorporated in numerous alloys. They have higher resistance to corrosion and are often used in production of engineering components. The common copper alloys are brass and bronze. Brass is a yellow alloy of copper with zinc and bronze is an alloy of copper with tin. The highest strength-to-weight ratio of any metal has titanium, sometimes called space age metal. It has a low density and is strong, lustrous, and corrosion-resistant (also to sea water). Therefore, titanium and its alloys are used in aerospace, marine and automobile industry. Properties of metals can be changed by plating which is surface-covering where a metal is deposited on a conductive surface. Metals can be plated for several purposes, especially for increasing corrosion resistance, but also to improve adhesion, to alter conductivity, to harden, to reduce friction, etc. For example zinc plating, tin plating, chromium plating, etc. VOCABULARY ability - schopnost above - nad accommodate vyhovovat, odpovídat actually ve skutečnosti amount - množství appreciable - patrný, zjevný article - článek based on - založený na basically - v podstatě best-known - nejznámější classify - (roz)třídit certain určitý coarse - hrubý common - běný content - obsah deciding - rozhodující depending on - závisející na e.g. - např. etc. - atd. especially - obzvlášť fluid - tekutina, kapalina focus - zaměřit (se) furthermore - kromě toho, dale ještě grade - stupeň, třída, kvalita group into - seskupit however - ale, avšak in comparison to - ve srovnání s inner - vnitřní like - jako meet the requirements - splňovat požadavky mine - těžit on the contrary - naopak poorly špatně, chabě previous - předcházející property - vlastnost purpose - účel purposely - záměrně rapidly rychle, náhle ratio - poměr recycle - recyklovat reprocess znovu zpracovat remarkable - významný roughly asi, zhruba several - několik specific - určitý suitable - vhodný significa nt - významný therefore - proto thus tudíž, tak upper horní, vyšší various různý, různorodý widely obecně, velmi reg. č. CZ.1.07/1.1.04/ str. 48 z 97

5 TECHNICAL TERMINOLOGY adhesion - přilnavost annealing - žíhání austenite - austenit brittle - křehký castability - slévatelnost combustible - vznětlivý component - součástka composition - složení conduction vodivost, vedení conductive - vodivý conductor - vodič cooling - (o)chlazení corrosive resistance - odolný proti korozi covering - kryt, potah density - hustota ductile - kujný, tažný durable - odolný durability - odolnost duralumin - dural element - prvek engineering - strojírenství fabrication - výroba, zhotovení ferrous - železný, železitý flexibility - pružnost fluidity - slévatelnost, tekutost friction - tření hardening - kalení heating - ohřívání heat treatment - tepelné zpracování hardness - tvrdost hypoeutectoid - hypoeutektoidní hypereutectoid - hypereutektoidní industry - průmysl - aerospace - letecký - automobile - automobilový - marine - námořní internal stresses - vnitřní pnutí lustrous - lesklý, třpytivý machinability - obrábitelnost, opracovatelnost machining - obrábění malleable - kujný, tvárný martensite - martenzit melting point bod tání metallic - kovový pearlite - perlit plating - pokovování production - výroba resistance - odolnost solidity - pevnost strength - síla, pevnost surface povrch transparent - průhledný wear resistance - odolnost proti opotřebení weight - váha VERBS add - přidat alter - změnit anneal - žíhat bend - ohýbat, ohnout connect - spojit contain - obsahovat create - (vy)tvořit deposit - položit determine - určovat differ - lišit se follow - následovat generate - vytvářet harden - kalit heat-treat tepelně zpracovat improve - zlepšit include - zahrnovat, obsahovat increase - zvýšit incorporate - zahrnout, začlenit influence - ovlivnit involve -zahrnovat, obsahovat machine - opracovat strojem maintain - udržet, zachovat manufacture - vyrobit, zhotovit obtain - získat, obdržet plate - pokovit punch - uhodit reduce - zmenšit, omezit replace - nahradit require - požadovat shape - obrábět, tvarovat soften - změknout tend - tíhnout k, být náchylný use - používat, užít weld - svařovat MATERIALS, ELEMENTS alloy - slitina reg. č. CZ.1.07/1.1.04/ str. 49 z 97

6 aluminum - brass - mosaz bronze - bronz carbon - cast iron - litina charcoal dřevěné uhlí ceramic - keramika chromium - chrom coal uhlí concrete beton copper - corundum - korund gold zlato iron - lead - olovo manganese - mangan molybdenum - molybden nickel - nikl ore ruda paper papír plastic umělá hmota, plast ruber guma sheet copper měděný plech silicon - steel - ocel stone kámen tin - titanium - wolfram - wolfram wood dřevo zinc - SPEAKING Exercise 1 Answer the questions. Exercise 2 1. Which metallic and non-metallic materials do you know? 2. What physical properties of steel do you remember? 3. What is heat treatment? 4. Why is steel heat-treated? 5. What do you know about cast iron? 6. Where is aluminum used and why? 7. Which 2 well-known copper alloys do you know? 8. Why is titanium called space age metal? 9. Why are metals plated? 10. What metals are good for plating? Decide whether the statements below are true or false 1. T / F Steel is an alloy. 2. T / F Steel that contains less than 0,8% carbon is called hypereutectoid. 3. T / F Aluminum is the most widely used ferrous metal. 4. T / F Heat treatment is the process of controlled cooling of metals 5. T / F Cast iron is an alloy of iron, silicon, carbon and other elements 6. T / F Steel is not often recycled because it loses its physical properties 7. T / F Copper is an electrical conductor. 8. T / F Brass is an alloy of copper with tin. 9. T / F Aluminum is used in aerospace industry because of its nice silver colour. 10. T / F Copper is softer than steel. VOCABULARY REVISION Exercise 1 Write down as many words as you can remember. (at least 3) reg. č. CZ.1.07/1.1.04/ str. 50 z 97

7 1 metallic material 2 non-metallic material 3 conductive 4 solid 5 corrosion-resistant Exercise 2 What are the properties of the following materials. conductive brittle corrosion-resistant malleable durable ductile solid ferrous lustrous light adhesive soft flexible 1. steel - 2. aluminum - 3. copper - 4. cast iron - 5. plastic - Exercise 3 Match the English and Czech words. 1. adhesion pružnost 2. castability pevnost 3. conduction odolnost 4. density žíhání 5. solidity přilnavost 6. machining vodivost 7. durability kalení 8. flexibility hustota 9. hardening slévatelnost 10. annealing obrábění reg. č. CZ.1.07/1.1.04/ str. 51 z 97

8 Exercise 4 Match the materials in the table with the definitions. Copper Tin Zinc Gold Iron Aluminum Steel A silver-coloured metal, light in weight, used for making cooking equipments, aircraft parts A very strong hard metal made iron, used for making vehicles, tools, knives, machinery, etc. A soft, red-brown metal through which heat passes easily, used in electrical equipment and to make coins. A soft white metal often combined with other metals or applied as a protective covering for iron and steel. A bluish-white metal used in a production of other metals and for covering iron, wire, A precious yellow metal used for making coins, ornaments, jewellery, etc. A common, very hard metal, used to make steel. Itn is also found in blood and in all living things REVIEW 1. Describe heat treatment. 2. Have you ever seen heat treatment? Where? 3. Name some metals that you know and give examples where you can use them. 4. What tool do you need when you heat-treat steel? reg. č. CZ.1.07/1.1.04/ str. 52 z 97

9 TALKING POINTS Semi-finished products What would be an ideal job for you? Would you like to be an engineer? What product from your everyday life was made by machining? PRE-READING Exercise 1 Label the shapes with the words below. A) B) C) D) E) I F) G) H) I) J) 1 square 6 Circle 2 triangle 7 I-shape 3 sphere 8 Pentagon 4 cube 9 Rectangle 5 oval 10 U-shape Exercise 2 Multiple-choice quiz. Choose the best answer. 1. LENGTH 4. DENSITY a. délka a. povrch b. hloubka b. hustota c. šířka c. váha 2. BREADTH 5. WEIGHT a. délka a. povrch b. hloubka b. hustota c. šířka c. váha 3. DEPTH 6. SURFACE a. délka a. povrch b. hloubka b. hustota c. šířka c. váha reg. č. CZ.1.07/1.1.04/ str. 53 z 97

10 READING SEMI-FINISHED PRODUCTS You, future engineers, should know what engineering is and what products are made in the process of machining thanks to engineers. Man has always tried to produce things to make his life easier. As years passed the society has progressed and man found new ways of productions. Engineering is the special discipline of designing and manufacturing materials, structures, machines and devices. Engineering components are often made from semi-finished products. Semi-finished products are partly machined shapes that later are manufactured into finished products. A semi-finished product should be as much as possible similar to a finished product. Labour and machines are used to make products and it is long and expensive process. The production becomes cheaper when normalized semi-finished goods are used. They are rough-machined and used more in 1 piece production and 2 short-run production. While unnormalized semi-finished products are often used in series production and 3 mass production. They are often made 4 according to the customer's specifications and therefore they are designed 5 precise with small machining allowance. Normalized semi-finished products: Blanks (blooms, billets, ) 6 Bars (circle, square, I,U-shaped) 7 Plates Strips 8 Pipes Wires Thin-walled profiles Blanks, bars, plates and slabs are produced by hot rolling or cold rolling and can be also calibrated by die drawing. Pipes are made by bending and welding sheets or plates, weldless pipes have to be rolled in a special way or extruded and then die drawn. Die drawing is also used to produce wires. Unnormalized semi-finished products: Castings Forgings Pressings Weldments Cuttings Soldered semi-finished products reg. č. CZ.1.07/1.1.04/ str. 54 z 97

11 VOCABULARY according to the customer s specifications na zakázku as much as possible co nejvíce engineering - strojírenství labour - práce make sth.easier - ulehčit pass - minout progress - pokrok similar - podobný society - společnost precise - přesný thanks to - díky therefore - proto use - používat while - zatímco customer - zákazník TECHNICAL TERMINOLOGY bend ohnout, ohžbag billet - sochor blank - předvalek bloom blok calibrate - kalibrovat casting - odlitek component součástka, součást cutting - odřezek device - zařízení die drawing tažení průvlaky extrude - protlačovat forging výkovek goods - zboží machine stroj - vyrobit, obrábět strojem - machining - obrábění machining allowance - přídavek na obrábění manufacture - vyrobit mass production - hromadná výroba (un)normalized - (ne)normalizované piece production kusová výroba pipe - trubka plate - plech pressing výlisek production - výroba rolling - válcování - hot rolling válcování za tepla - cold rolling válcování za studen rough-machined hrubě obráběný sheet - plech soldered semi-finished product - pájený polotovar series production sériová výroba strip - pás semi-finished products - polotovary shape - tvar short-run production - hromadná výroba thin-walled profile tenkostěnný profil weld - svářet weldless pipe bezešvé trubky weldment - svarek wire - drát SPEAKING Exercise 1 Answer the questions. 1. What is engineering? 2. Why are semi-finished products used? 3. Can you name any normalized semi-finished products? 4. Can you name and unnormalized semi-finished products? Exercise 2 Decide whether the statements below are true or false. 1. T / F Engineers design and manufacture materials, structures, machines, T / F Blanks, bars, plates and slabs are produced by hot rolling. 3. T / F Normalized semi-finished products are used in mass production. 4. T / F Die drawing is also used to produce bars. reg. č. CZ.1.07/1.1.04/ str. 55 z 97

12 VOCABULARY REVISION Exercise 1 Find the synonyms in the article and translate them. a) accurate b) tube c) quantity production d) rod e) short-run production f) small-lot production g) per order h) sheet Exercise 3 Are these products normalized or unnormalized? weldments pipes blanks castings forgings wires cuttings reg. č. CZ.1.07/1.1.04/ str. 56 z 97

13 Exercise 4 Solve the crossword B 14 2 H D 16 9 E 3 C 15 8 G 17 6 F A Solution: A B C D E F G H ACROSS 1. svarky 2. odřezky 3. výkovky 4. zboží 5. tyče 6. plechy 7. výlisky 8. trubky 9. předvalky DOWN 11. dráty 12. válcování 13. polotovar 14. tenkostěnný profil 15. pás 16. bloky 17. odlitky reg. č. CZ.1.07/1.1.04/ str. 57 z 97

14 TALKING POINTS Machining 1 You know what is machine? What do you think that machining is? What is CNC machine? What is the hardest material in the world? What is it used for? PRE-READING Exercise 1 READING Without a dictionary, try to translate the following words into Czech. workpiece thermal process - deviation high-speed steel - electro-erosion machining - water-jet - MACHINING 1 Machining is the process of removing material from a workpiece to achieve desired shape and size. The material is cut by sharp cutting tools (such as lathes, milling machines and drill presses) into the form of chips, sometimes called also swarf. Machining is a precise procedure compared to forming, molding and casting and therefore it is necessary where high degree tolerances on dimensions and high-quality finished products are required. A finished product would be a workpiece that meets the specifications set out by engineering drawings. A lot of factors play an important role to achieve the desired product, e.g. tool size, tool shape, level of contact with the tool, the depth of the cuts and also relative motion. During machining process a relative motion is produced between the tool and the workpiece. The primary motion is called cutting speed and the secondary motion is called feed. The cutting speed of the machine is the rotation of the workpiece against the tool. Feed is the distance of tool travel during one revolution of the part. The type of material to be cut is a deciding factor when determining the correct speed and feed rate. Machinist also has to keep in mind that a machining allowance on specific parts of a given workpiece is needed. Unlike a tolerance, which is an unplanned deviation, machining allowance is planed deviation. Machining has to be viewed as a system consisting of the machine the tool the workpiece but also as a group of manufacturing operations. There are two categories of machining, traditional and nontraditional. The machining operations that use single- or multi-point cutting tools (each with a clearly defined geometry) to remove material in the form of chips are traditional methods. They include turning, milling, dribling, planning, grinding, honing, loping, etc.. Whereas the use of chemical, thermal, or electrical processes to machine a workpiece and remove material is nontraditional method. Nontraditional machining includes a wide range of operations used for special purposes, e.g. laser, waterjet and electro-erosion machining. reg. č. CZ.1.07/1.1.04/ str. 58 z 97

15 Cutting tool is a device used to remove the unwanted material from a given workpiece. Different materials can be used for cutting tools but they must have the following properties: high hardness (higher than a workpiece), heat and wear resistance, bending strength, toughness and thermal stability. There are only few materials used for cutting tools: High-speed steel This material is the least-expensive and shortest-lived. Indexable carbide These tools are more expensive than steel but they last longer, and can be run much faster. They are used in the long run. Ceramic It is a cheap tool material which can cut almost any metal but it is very brittle Diamond It is the hardest known material and is suitable for machining very hard materials such as ceramics. Cubic boron nitride CBN has been developed as an alternative to diamond for machining ferrous materials and unlike diamond it is thermally stable. During the machining process it is also important to study the chip formation because it affects the surface finish, temperature, cutting forces, tool life and dimensional tolerance. Understanding the chip formation will allow us to determine the machining speeds, feed rates and depth of cuts for efficient machining. The quality of a workpiece and cutting conditions influence the properties of chips. The chips can be classified into three types 1. Discontinuous or segmental chips 2. Continuous chips 3. Continuous chips with built-up edge VOCABULARY affect ovlivnit allow dovolit classify (roz)třídit (do skupin) conditions podmínky defined definovaný degree stupeň, míra depth hloubka desired - požadovaný device zařízení, přístroj distance vzdálenost efficient výkoný following - následující formation tvorba given daný level úroveň, stupeň motion pohyb necessary nutný precise přesný primary primární properties vlastnosti purpose účel range škála, rejstřík rate poměr / rychlost relative paralelní revolution otáčka, obrátka rotation otočení shape tvar sharp ostrý size velikost surface povrch understanding porozumění unwanted nechtěný TECHNICAL TERMINOLOGY bending strength pevnost v ohybu casting lití ceramic keramika cubic boron nitride kubický nitrid bóru cutting force řezná síla cutting speed řezná rychlost cutting tool řezný nástroj deviation odchylka diamond diamant dimension rozmě drilling vrtání drilling press sloupová vrtačka engineering drawing technický výkres feed posuv feed rate velikost posuvu forming tváření grinding broušení hardness tvrdost heat resistance odolnost proti žáru honing honování chip tříska indexable carbide slinutý karbid lapping lapování lathe soustruh machine stroj, obrábět machining obrábění milling - frézování milling machine - fréza moulding strojové matricování multi-point tool reg. č. CZ.1.07/1.1.04/ str. 59 z 97

16 planning - hoblování single-point tool swarf - třísky thermal stability tepelná stálost toughness tuhost, pevnost travel (tech.) pohyb, posun turning soustružení wear resistance odolnost proti opotřebení workpiece obrobek VERBS achieve dosáhnout determine určit include obsahovat, zahrnovat meet specifications splňovat přesné stanovení play an important role hrát důležitou roli remove odstranit require vyžadovat set out rozvrhnout, vytýčit view posuzovat, vidět SPEAKING Exercise 1 Exercise 2 Answer the questions. 1. What is machining? 2. What is more precise machining or forming? 3. What machining deviations are mentioned in the article? Which one is the unplanned? 4. What traditional machining methods do you remember? 5. What nontraditional machining methods do you remember? 6. Why is chip formation important? Decide whether the statements below are true or false, according to what you read in the article. 1. T / F The depth of the cuts plays an important role to achieve the desired product. 2. T / F The primary motion is called cutting feed and the secondary motion is speed. 3. T / F Machining is the system consisting of the workpiece, the tool and the machine. 4. T / F Traditional machining uses cutting tools to remove material in the form of chips 5. T / F Water-jet machining and laser machining are used for special purposes. 6. T / F There are a few types of chips, e.g. continuous chip, discontinuous chip, etc. VOCABULARY REVISION Exercise 1 Translate the words on the right and complete the table. All the words in the table are ing ending! 1 ing - Soustružení 2 ing - Frézování 3 ing - Tváření reg. č. CZ.1.07/1.1.04/ str. 60 z 97

17 4 hon ing - Honování 5 ing - Vrtání 6 ing - Obrábění 7 ing - Broušení 8 ing - Hoblování 9 ing - Řezání 10 ing - Lapování Exercise 2 Match the words on the left with the definitions on the right. 1. Workpiece 2. Chip 3. Nontraditional machining 4. Single-point tool 5. Traditional machining 6. Multi-point tool a) The group of machining operations that use single- or multi-point tools to remove material in the form of chips. b) A part that is being worked on during manufacturing. c) An unwanted piece of metal that is removed from a workpiece. d) A machining tool that has two or more cutting edges. e) A machining tool that has one cutting edge. f) The use of chemical, thermal, or electrical processes to machine a workpiece and remove material. reg. č. CZ.1.07/1.1.04/ str. 61 z 97

18 Exercise 3 Translate the words on the right and fill in the crossword. 1 1 tříska 2 2 tuhost, pevnost 3 3 lití 4 4 soustruh 5 5 obrobek 6 6 tvrdost 7 7 broušení 8 8 Hloubka 9 9 Účel vlastnost obsahovat, zahrnovat REVIEW 1. What is machining? 2. There are 2 categories of machining, which ones? Give examples! 3. What material of cutting tools do you remember? 4. Why is chip formation important? reg. č. CZ.1.07/1.1.04/ str. 62 z 97

19 Machining 2 TALKING POINT What is machining? READING MACHINING 2 Machining is a very important process in today s engineering and manufacturing practice. There are two basic methods of machining, conventional and non-conventional., sometimes also referred to as traditional and untraditional. CONVENTIONAL PROCESSES They are based on removing material in the form of chips by using a wedge shaped tool which is harder than a workpiece. The conventional processes are turning, milling, drilling, broaching, planing and slotting or finishing operations honing, lapping, superfining, grinding,... Turning is one of the most basic machining operations used to produce cylindrical components. The main rotating cutting motion is done by a workpiece, while feed and infeed is done by a tool. Turning is performed on a machine called a lathe (the process is controlled manually) or on a modern computer numerical controlled (CNC) machine (the process is controlled by computer). When turning, the workpiece is held and rotated around a horizontal axis while being formed to size and shape by a cutting tool, called a turning tool. The turning tool is stationary, single-point and parallel to the surface. The workpiece is mounted in a chuck, collet or faceplate. Typical examples of the products made by turning process include internal or external cylindrical components or threads. The lathe can be also used for other machining operation like drilling or boring. Milling is a machining process for producing parts having flat, angular or curved shapes like grooves, helixes, geared wheelss, etc. In the milling process, the cutting motion is carried out by a rotating tool while feed and infeed is done by a workpiece in three perpendicular directions vertical, longitudinal or crosswise. The workpiece is commonly held in a vise or similar device clamped to a table, that can move, and fed against a rotating multiple-tooth tool known as the milling cutter. Drilling is a machining process of making cylindrical holes and it is extensively used because most of components have one or more holes in them. The cutting motion and feed is performed by a rotating tool while the infeed is given by the radius of a drill. The drilling operation can be carried out on a drilling machine but a lathe can be used for drilling as well. The tool used for making holes is called a drill. The workpiece remains stationary and the drill is rotated as well as fed into the workpiece. The vertical motion of the drill is the feed in drilling operations. There are various finishing operations used for enlarging an existing hole and to achieve greater accuracy of the diameter of a hole, e.g. boring, counterboring, countersinking or reaming. Finish machining operations are grinding, honing, lapping, and superfinishing. They are used to improve surface finish (by removing scratches or machine marks), abrade hard materials and increase geometric form of a surface. reg. č. CZ.1.07/1.1.04/ str. 63 z 97

20 NON-CONVENTIONAL PROCESSES Conventional machining of some alloys into complex shapes is difficult, time-consuming and sometimes impossible. These advanced alloys are very hard, high-strength, temperature-resistant or too brittle. To overcome these problems, non-conventional operations are used. They are characterized by utilizing some form of energy for metal machining instead of a traditional tool. They can be broadly classified according to the type of energy employed, e.g. water jet, ultrasonic, electron-beam, laser-beam, plasma-beam, chemical cutting, etc. These non-conventional processes play an important role in modern manufacturing industries, especially, in aircraft, aerospace and nuclear industries or tool and die making industry. VOCABULARY abrade brousit, obrušovat accuracy - přesnost achieve - dosáhnout angular - hranatý axis - osa chip - tříska chuck - sklíčidlo clamp - upínat collet - kleština component - součástka crosswise - příčný curved zakřivený, ohntý cutting motion řezný pohyb cylindrical - válcový device zařízení, přístroj diameter - průměr drill - vrták drilling machine - vrtačka enlarge rozšířit, zvětšit extensively - značně faceplate lícní upínací deska feed - posuv feed dávkovat, podávat geared wheel ozubené kolo groove - drážka hold - držet hole - díra horizontal - vodorovný important - důležitý improve- zlepšit increase - zvýšit infeed - přísuv lathe - soustruh longitudinal - podélný mark stopa, značka milling cutter - fréza motion - pohyb mount upevnit, přimontovat multiple-tooth - mnohozubý parallel - rovnoběžný perform - vykonávat perpendicular - kolmý radius dosah, poloměr působnosti refer týkat se, vztahovat se remain - zůstat remove - odstranit rotate točit, otáčet se scratch škrábanec, rýha shape - tvar single-point- jednobodový size - velikost helix - šroubovice stationary - nehybný surface - povrch thread - závit tool - nástroj utilize - využít vertical - svislý vise - svěrák wedge - klín TECHNICAL TERMINOLOGY Boring - vyvrtávání Broaching - protahování Conventional - konvenční Drilling vrtání Finishing dokončovací operace, konečná úprava Grinding - broušení Honing - honování Lapping - lapování Milling - frézování Non-conventional - nekonvenční Planning - hoblování Reaming vystružování Recessing - zahlubování Slotting - obrážení Superfinishing - superfinišování Turning - soustružen SPEAKING Exercise 1 Answer the questions. 1. What is the diference between conventional and non-conventional processes? 2. What do we call the machine used in turning? 3. What operations can be done on a lathe? 4. What device is used during milling to hold the workpiece? reg. č. CZ.1.07/1.1.04/ str. 64 z 97

21 5. What is the name of the machining operation used for making holes? 6. What finishing processes do you know and why are they employed? 7. Name some non-conventional processes. Exercise 2 Decide whether the statements below are true or false. 1. T / F Turning, drilling and laser-beam machining are conventional machining processes. 2. T / F Products made by turning include internal cylindrical components or threads. 3. T / F In conventional processes, a tool is used to cut material, whereas in non-conventional processes, some form of energy is used to remove material. 4. T / F Drilling is a process for producing flat, angular or curved shaped components. 5. T / F Conventional machining of some alloys into complex shapes is not easy and sometimes not possible. VOCABULARY REVISION Exercise 1 Correct the spelling planning miling honning dificcult engeniring proces metod acuraccy britle laser-beem Exercise 2 MACHINE Fill in the table. Turning Milling Drilling Broaching broaching machine Planning Slotting TOOL Grinding Exercise 3 Fill in the table. Cutting motion Feed Infeed Turning workpiece tool tool Milling tool workpiece Drilling tool given by a radius of a drill Broaching tool Tool reg. č. CZ.1.07/1.1.04/ str. 65 z 97

22 Planning, Slotting workpiece tool Grinding tool tool Exercise 4 Translate the following article into English SOUSTRUŽENÍ Soustružení je nejjednodušší a nejužívanější způsob obrábění. Je to obráběcí metoda používaná pro zhotovení válcových ploch, většinou jednobřitým nástrojem. Stroje se nazývají soustruhy. Soustruhy používáme nejen k soustružení, ale taky k vrtání nebo vyvrtávání. Exercise 5 Choose one conventional machining operation and describe it in 3-5 sentences. You can use vocabulary from exercise 2 and 3. reg. č. CZ.1.07/1.1.04/ str. 66 z 97

23 Exercise 6 Solve the puzzle. W K H O N I N G M R O F L I S E O C D E E F N I N A G I A N P N R U E E R S L O O T C E P T I D K H S P E F E E D U S H P E N G P C O L L E T O I R G T I R D N I E N B O A H U I N I A N N L I E L L D A T N N D I R L G A E D C O N V E N T I O N A L L L E N E H P M I L L I N G A I R I M I S U R F A C E H N G A C H I N R E G N I M A E R S G R O O V E G sklíčidlo C konvenční C upínací vložka C vrtání D posuv F tvar,forma F broušení G drážka G honování H díra H vnitřní I přísuv I lapování L soustruh stroj metoda ; frézování hoblování vystružování obrážení S povrch vřeteno S nástroj soustružení svěrák obrobek W L M M M P R S T T V reg. č. CZ.1.07/1.1.04/ str. 67 z 97

24 Metal forming processes TALKING POINTS Use dictionary if necessary. Brainstorm as many tools as you can. What tool do you use at home and when. What tool do you use in your workshop lessons What tool do you think is used to form metals? READING METAL-FORMING PROCESSES Two important metal shaping processes are machining and forming. Unlike machining, forming is a chipless process, which means that energy and money for removing and depreciating wasted material is saved. Forming is widely used nowadays, more than machining. In forming process, a force is applied to a workpiece to modify its geometry rather than remove material (like in machining processes). So the workpiece is plastically deformed without reducing its structural cohesion and physical properties of metal are improved. Forming is used in mass production, because of money, energy and also raw material savings and high-speed production, while machining is used in piece production, because of higher precision. Metal material can be formed in cold or hot conditions. If the temperature during processing is more than the recrystallization temperature of the metal, the process is called hot forming or hot working and it is cold forming or cold working if the temperature is kept bellow the temperature of recrystalization. 1) Hot forming processes: Forging can be defined as the process wherein a workpiece is plastically deformed by applying compressive force. Forging is the oldest known metal forming process. Nowadays, it is an important manufacturing technique used to produce high-strength components, stronger than by any other metalworking process. It can be performed in different ways (pressing or hammering) and temperatures (usually hot). Forging temperature is a temperature at which a metal becomes soft or its shape can be changed by applying a relatively small force without creating cracks in metal. There are two types of forging processes: open die forging and closed die forging). Open die forging (hand forging) is the term used for compressive forming performed between plain dies with no restriction at the ends. During deformation the workpiece is squeezed between flat dies or dies of simple shape while it is hammered or pressed. It is usually used for making heavy products (over 150 ton) that are too large for close die forging. However, because of lower cost over component life, low volume parts can be forged during open die forging process as well. Today, it is also considerably used for preforming material for subsequent metal forming process. In closed die forging (impression die forging) the workpiece is plastically deformed in a die. The workpiece is confined in a die which is a two-part form attached to a hammer anvil or press. The cavity of a die has an reg. č. CZ.1.07/1.1.04/ str. 68 z 97

25 inverse pre-formed profile of the desired part and it must be resistant to thermal and mechanical fatigue. The workpiece is usually heated before placing in a die and then is pressed or hammered until it flow and fill the die cavity. The forging is done under great pressure and while the two halves of a die are brought together a portion of the metal flows beyond the die cavity to form a flash. The flash is excess metal and after cooling of the workpiece it is trimmed out to achieve the end product geometry. Close die forging can be used to produce difficult geometries with high accuracy. It is the most common method of forging and is cost-effective for high volume production. 2) Cold forming processes: These processes are applied for soft materials otherwise the workpiece would crack. The force required for cold forming must be much higher than in hot forming. Cold forming is a cheap high-speed manufacturing technique. Cold forming processes include the following: blanking, bending, extrusion, rolling and many others. Blanking is a metal forming operation in which a piece of sheet metal is removed from a larger piece by applying a great shearing force. In this process, the removed piece, the blank, is not scrap but the desired part. Blanking can be used to cut out parts in almost any 2D shape, but is most commonly used to cut workpieces with simple geometries that will be further shaped in subsequent processes. Bending is a cold forming process during which material is plastically deformed into various bend angles. The act of bending results in both tension and compression in the sheet metal. The outside fibres are subjected to tensile strain and they extend while the inside fibres are subjected to compressive strain and they shrink. The compressive stress changes into tensile stress at neutral axis where neither compressive nor tensile strain occurs. For bend stabilization the bend axis should be perpendicular to fibre direction. When the bending pressure is removed at the end of the deformation operation, the material has a tendency to partially return to its original shape. Due to this elastic recovery, called spring-back, it is necessary to overbend the sheet to achieve the desired bend angle. Drawing is a metal forming process which uses tensile forces to stretch metal into the desired shape. The workpiece is stretched around a plug and then pulled through a die. Common shapes for drawn products include cylinders for aluminium cans, kitchen sinks or cups for baking pans. The metal used in this process must be malleable as well as resistant to stress and tension damage. Extrusion is the process by which long straight metal parts with various cross-sections can be produced. The cross-sections vary from round, rectangular, to L shapes, T shapes, tubes and many other different types. Extrusion is done by squeezing metal in a closed cavity and then pushed through an extrusion die of the desired cross-sections. This process can be used for those materials which can withstand the stresses created by extrusion, e.g. lead, tin, aluminium alloys, coper, titanium, steel, etc. VOCABULARY accuracy přesnost achieve dosáhnout anvil kovadlina attach připevnit axis osa baking pan with cups plech na muffiny beyond mimo, za blank výstřižek blanking die střižnice blanking press střihadlo blanking punch střižník cavity dutina chipless beztřískový compression tlak compressive stlačující conditions - podmínky considerably značně crack prasklina, trhlina - praskat cross-section průřez cutout výřez cylinder válec deform přetvářet, měnit tvar depreciate znehodnotit (forging) die zápustka excess nadbytek extend prodlužovat, roztahovat extrusion die průtlačnice fatigue únava (materiálu) reg. č. CZ.1.07/1.1.04/ str. 69 z 97

26 fiber vlákno fill vyplnit flash výronek flow téct force síla fracture zlomit se gap mezera grain structure struktura zrnění hammer kovat, tlouct kladivem - buchar, kladivo hammering kování bucharem (kladivem) high-strength s vysokou pevností inverse obrácený malleable tvárný mass hmota, množství modify upravit performing předběžné tváření, předtvarování plain plochý, rovný plug razník, tažník portion část precision přesnost processing zpracování productivity rate produktivita profile profil, tvar rate tempo / poměr raw material surovina recovery návrat (do původního stavu) reduce zmenšit,snížit remain zůstat resistant odolný restriction omezení result má za následek scrap odpad shearing stříhací sheet metal plech shrink zkracovat se, smrštit se sink dřez spring back odpružení squeeze sevřít, stlačit stabilization zpevnění strain napětí stress napětí subjected vystavený (tahu/tlaku) subsequent následující tension tah trim out odstřihnout vary lišit wastage - odpad withstand - odolat TECHNICAL TERMINOLOGY blanking střihání close die forging zápustkové kování drawing - tažení extrusion protlačování forming tváření forging kování open die forging volné kování reg. č. CZ.1.07/1.1.04/ str. 70 z 97

27 SPEAKING Exercise 1 Answer the questions. 1. What is the difference between machining and forming? 2. What is forging? 3. What is a die and what is the difference between the dies used in open or close die forging? 4. What is flash? 5. Why must be the materials soft and malleable when they are formed in cold conditions? 6. What is the equipment used in blanking process? 7. What force can occur while bending tension or compression? And where? 8. What is a spring-back? 9. What drawing products do you know? 10. What materials should be used in extrusion process? Exercise 2 Decide whether the statements below are true or false, according to what you read in the article. 1. T / F Machining and forming are two important processes of shaping by removing material from workpiece to achieve a desired shape. 2. T / F In bending process, the neutral axis is a line where are no tensile and compressive stresses and strains. 3. T / F Close die forging is very expensive for high volume production 4. T / F Unlike hot forming, cold forming is the process where greater force must be used to shape the metals 5. T / F Actually, a blank is not a waste product but a desired product of blanking. 6. T / F In bending, inside fibers are affected with a tensile force and outside a with compressive force. 7. T / F Drawing is used for utensils production. 8. T / F The cross-section of a extrusion product can have just 5 shapes round, rectangular, L shapes, T shapes and tubes. 9. T / F Open die forging is utilized usually in production of heavy parts. 10. T / F Forging temperature is a temperature which metal workpiece must achieve to be smoothly forged without creating cracks VOCABULARY REVISION Exercise 1 Choose the correct process. 1. Extrusion / Forging is a process of producing a metal component by hammering. 2. Blanking / Bending is a mechanical process of shearing metal workpiece into a desired shape. 3. Drawing / Extrusion is a forming method in which a workpiece is forced through a shaped die. 4. Drawing / Extrusion is a technique of pulling a metal through a hole of a die to change its shape. 5. Forging / Bending is a metal forming process when workpiece assumes a curved shape. Exercise 2 Translate into English: 1. Oproti volnému kování, zápustkové kování dosahuje větší přesnosti. reg. č. CZ.1.07/1.1.04/ str. 71 z 97

28 Technická angličtina pro střední průmyslové průmyslové školy se zaměřením na elektrotechniku a strojírenství Tah přechází v tlak na neutrální ose vlákna v této ose nejsou namáhána na tlak ani na tah. Materiál musíme ohnout více kvůli odpružení. Úhel odpružení můžeme najít v tabulkách. Teplý kov se vloží do dutiny zápustky, kde se materiál deformuje a vyplní dutinu. Teplota tváření za tepla je nad teplotou rekrystalizace, teplota tváření za studena je bod touto teplotou. Exercise 3 Look at the photograph. photog In pairs, answer the question. 1. Who do you think the man is? 2. Where do you think he is? 3. What do you think he is doing? 4. Describe the whole process. 5. Have you ever done this in your school workshop? reg. č. CZ.1.07/1.1.04/ str. 72 z 97

29 Exercise 4 What do you know about the dies listed bellow? Forging die Blanking die Extrusion die Exercise 5 Choose one metal forming operation and describe it in 3-5 sentences. reg. č. CZ.1.07/1.1.04/ str. 73 z 97

30 TALKING POINTS Metal joining processes Work in pairs. 1. Use knowledge gained in your Technology lessons and write down techniques which can be used to connect 2 metal material. (use dictionaries if necessary) 2. Have you ever tried any of these techniques in your school workshops? 3. Could you briefly describe any of them? 4. Do you like your lessons in your school workshop? Why?/Why not? 5. Look at the pictures bellow and discuss what the people are doing. reg. č. CZ.1.07/1.1.04/ str. 74 z 97

31 a)... b)... c)... d)... e)... READING METAL-JOINING PROCESSES Joining of metal materials is required when the desired component cannot be made by means of metal forming or machining. The essential metal joining operations are welding, soldering, adhesive bonding, riveting and bolting. Each of these metal joining processes has their own pros and cons. WELDING is the most common way of joining two workpieces to produce a single piece of metal. The coalescence of metals is done by applying heat, pressure or both and the weld is made when the edges of workpieces are melted so that they fuse permanently. This is done with or without the use of a filler material. According to the energy sources used for joining we distinguish several types of welding, such as gas welding, arc welding, laser welding, electron beam welding, resistance welding, etc. SOLDERING is another joining process in which two workpieces are joined together with a molten metal, a solder. The solder, a cohesive metal, is characterized by a lower melting point than the joining metal. In the process, the surface of workpieces is cleaned - initially mechanically and then by applying a melting flux on the reg. č. CZ.1.07/1.1.04/ str. 75 z 97

32 workpieces. Afterwards, the workpieces are heated with a soldering iron above the melting point of the solder and the solder is drawn into the joint where it is smoothly spread to form a bond. Unlike welding the edges of workpieces are not melted and fused, they are joined through a solder. So the advantage of soldering is that dissimilar materials may be joined. ADHESIVE BONDING is an effective metal-joining process used to fasten two workpieces together through an adhesive which must be highly adhesive and cohesive. Several types of adhesives can be utilized and the best choice of adhesive depends on the materials to be bonded. The bond is strong, corrosion resistant, cleanlooking and often has a good heat, sound and electrical insulation. Adhesive application is also crucial for bond quality so the way of adhesive distribution and the depth of distributed layer are very important. Different materials with dissimilar thicknesses can be employed in this process. RIVETING is a joining technique wherein two workpieces are connected with rivets. A rivet is a permanent metal fastener in a shape of a pin with a head on one end and a plain tail, a shank, on the other. The rivet is placed in a punched hole passing through two connecting workpieces. Then, the part of shank protruding from the hole is hammered or pressed to form a second head to the rivet and to connect the workpieces together. The inserting rivets may be either hot or cold depending on the ductility of the rivet material. Riveting is relatively cheap, strong and can join dissimilar materials with different thicknesses but it is now hardly seen. BOLTING refers to a temporary method of joining metal materials. The workpieces is connected by a threaded fastener, bolt. It comprises of a hexagonal head and a circular shank which may be fully or partly threaded. The bolt is screwed in a threaded hole passing through two workpieces and then fully tightened. The bolted joint can withstand huge amount of pressure. Bolting is very rapid method that requires less skilled labour therefore it is economical. The advantage against other joining methods is that the bolted joints can be easily disassembled by removing bolts. VOCABULARY above nad adherent přilnavý, lepený adhesive lepidlo - přilnavý, lepící affect působit afterwards poté, potom apply aplikovat, nanést assemble dát dohromady assume osvojit si bolt šroub (s maticí) bond pojivo, spojení spojit, slepit coalescence sloučení cohesive soudržný comprise obsahovat, skládat se z conditions podmínky crucial rozhodující desired požadovaný disassemble rozebrat dissimilar různý, rozdílný distinguish rozlišovat draw táhnout ductility - tvárnost edge konec effective účinný, užitečný employ používat ensure zajistit fasten připevnit fastener spojovací prvek filler tmel, výplň flame - plamen flux tavidlo fuse roztavit hammer buchar, kladivo heat teplo hexagonal šestiboký initially nejdříve insert vložit instantly okamžitě insulation izolace joint spoj, spojení labour práce layer vrstva low cost levný melt tavit melting point bod tání molten roztavený obtain získat, obdržet pass through procházet pin špendlík pressure tlak proper vhodný pros and cons důvody pro a proti punched děrovaný rapid - rychlý refer týkat se, vztahovat se require vyžadovat resistance odolnost resistant odolný screw šroubovat separate oddělit several několik shank dřík (šroubu, nýtu) skilled kvalifikovaný reg. č. CZ.1.07/1.1.04/ str. 76 z 97

33 smoothly hladce source zdroj spread rozprostřít tail spodní konec, ocas temporary dočasný tension napětí thickness tloušťka threaded závitový, se závitem thus tudíž, tedy unlike na rozdíl od utilize využít variety rozmanitost withstand odolávat, snášet TECHNICAL TERMINOLOGY adhesive bonding lepení bolting spojení šrouby metal joining spojování kovových materiálů riveting nýtování rivet nýt soldering pájení solder pájka soldering iron páječka welding svařování arc welding svař. elektrickým oblokem gas welding svař. plamenem electron beam welding svař. elektron. paprskem resistance welding svař. el. odporem SPEAKING Exercise 1 Answer the questions. 1. What are the basic joining processes? 2. What happens after applying heat on the edges of connected workpieces? 3. What is a solder? 4. What is used as a joining material in adhesive bonding? 5. What is important during the adhesive application? 6. What is the name of the fastener used in the riveting process? 7. Is bolting a permanent or temporary joining process? Exercise 2 Decide whether the statements below are true or false. 1. T / F In welding process, the connection of two workpieces is done through heating the edges of workpieces until they melt and then fuse. 2. T / F Welding is the most common joining process. 3. T / F A solder is a molten metal used to connect two workpieces. It is characterized by having low melting point, lower than melting point of soldered workpieces. 4. T / F Dissimilar materials with different thickness can be used in soldering, riveting and adhesive bonding. 5. T / F Today, riveting is not used very much. 6. T / F Bolting is a temporary process and the bond can be easily broken by removing the bolts. reg. č. CZ.1.07/1.1.04/ str. 77 z 97