UNIT 5. LASER BEAM MACHINING

Exercise 1. Please, revise the information of the previous unit. Compose the sentences and answer the following questions:

1) of unconventional What you types tools do know machine?

2) beam What laser is machining?

3) What used is machining for usually laser-beam?

Exercise 2.What do these abbreviations stand for? Give definition of UNIT 5. LASER BEAM MACHINING every process.

PAM, LBM, EDM, ECM, USM.

Exercise 3: Learn the new words and word combinations:

Semiconductor wafers – полупроводниковые пластинки

To collimate – коллимировать, сводить в параллельный пучок

Scribing – гравирование; нарезание кристалла

Patterning – формирование изображения; формирование рисунка

Adjacent – смежный

Precision – точность; четкость, аккуратность

Percussion – столкновение

Coaxial – имеющий общую ось

Exercise 4.Read and translate the following text.

LASER BEAM MACHINING

Laser UNIT 5. LASER BEAM MACHINING-beam machining (LBM) is accomplished by precisely manipulating a beam of coherent light to vaporize unwanted material. LBM is particularly suited to making accurately placed holes. It can be used to perform precision micromachining on all microelectronic substrates such as ceramic, silicon, diamond, and graphite. Examples of microelectronic micromachining include cutting UNIT 5. LASER BEAM MACHINING, scribing and drilling all substrates, trimming any hybrid resistors, patterning displays of glass or plastic and trace cutting on semiconductor wafers and chips.

In laser beam machining (LBM), an intense beam of collimated, single wave-length, in-phase light is focused by an optical lens onto the workpiece point UNIT 5. LASER BEAM MACHINING to be machined. The light absorbed by the workpiece is converted to heat, which melts and vaporizes the workpiece material. Molten material is evacuated from the cut by the adjacent vaporization turbulence which typically occurs in drilling operations, or by the use of an "assist gas" in cutting operations. Laser UNIT 5. LASER BEAM MACHINING beam machining uses a directional, coherent, monochromatic beam of light to achieve precision in cutting and drilling. The intensity of this light produces a tremendous amount of heat at the point of application to the workpiece, and laser beam machining can take place at relatively high speeds.

A number UNIT 5. LASER BEAM MACHINING of different types of lasers are used in laser beam machining, each with certain advantages for different operations or applications. The most commonly used lasers for machining are Nd:YAG lasers, which have certain advantages for hole drilling due to their higher pulse energy, and CCh gas lasers, which UNIT 5. LASER BEAM MACHINING have certain advantages in cutting since they are capable of delivering much higher average power. Lasers may be operated in either pulsed or continuous-wave (CW) modes. The most powerful CCb lasers, however, are operable only in CW mode. CCb lasers can have output power generally UNIT 5. LASER BEAM MACHINING ranging from 100 to 2000 W when pulsed and from 250 to 50(K) W in CW mode. Some lasers are capable of an output power of 25,000 W.

A 1250-W CO2 laser can cut mild steel at speeds ranging between 40 and 140 crrr/min, depending on material thickness. At a thickness of 12 mm, the UNIT 5. LASER BEAM MACHINING cut can be 40 enrr/min. At a thickness of 2 mm, a 1250-W CO2 laser can cut at a rate of 140 enrr/min. Aluminum is generally cut at about one-half the speed of carbon steel with a CO2 laser because of the high thermal conductivity of the aluminum. In cutting UNIT 5. LASER BEAM MACHINING applications, the laser beam may be "transmitted" and "switched" by using mirrors to manipulate the beam, or with Nd.YAG lasers by the use of a combination of fiber optic cables and switches. Below is the typical average power range and maximum pulse energy for the two types of lasers most UNIT 5. LASER BEAM MACHINING commonly used in laser beam machining.

In the application of laser beam machining, it is possible to perform the operations of drilling and cutting with speed and precision. For instance, percussion (i.e. repeated pulse) drilling of Inconel 718 with a 250-W Nd:YAG laser can produce accurate holes UNIT 5. LASER BEAM MACHINING 12 mm deep in under 10 sec and holes 25 mm deep in 40 sec. Length-to-diameter ratios are limited to about 30 or 40 to 1 with conventional Nd: YAG lasers. However, other laser technologies allow the length-to-diameter ratio to be higher. Frequently, gas is used to assist laser beam machining. A coaxial UNIT 5. LASER BEAM MACHINING columnar flow of gas (oxygen, air, or inert gas) at pressures ranging from 1 to 6 bar expels molten metal from the cut. Oxygen assists in cutting steel and other materials at an increased rate because of the oxidation reaction with the metals.

Laser beam machining uses thermal energy UNIT 5. LASER BEAM MACHINING to drill and cut with speed arid precision that traditional machining methods often cannot duplicate. Its applications are becoming more varied as new techniques are developed.

Exercise 5.Answer the questions to the text, using the active vocabulary of the lesson.

1) How does laser beam machining work?

2) When using UNIT 5. LASER BEAM MACHINING LBM, what is the difference between cutting operation and drilling operation process?

3) Why can laser beam machining take place at relatively high speeds?

4) What are the most commonly used lasers for machining? What are the advantages of them?

5) What operating modes for lasers do you know?

6) Why is it UNIT 5. LASER BEAM MACHINING necessary to transmit or switch a laser beam?

7) Describe the working process of the gas assisted laser beam machining.

8) Why does LBM work with such a speed and precision?

Exercise 6.Match the words and expressions on the left with those on the right:

1) optical lens a) мягенькая сталь

2) molten material b) импульсная UNIT 5. LASER BEAM MACHINING энергия

3) drilling operation c) оптическая линза

4) cutting operation d) процесс сверления

5) laser beam e) лазерный луч

6) pulse energy f) расплавленный материал

7) output power g) резание

8) mild steel h) выходная мощность

9) carbon steel i) реакция окисления

10) oxidation reaction j) углеродистая сталь

Exercise 7. Complete the sentences with given words and translate them into Russian:

Beam of light, modes, mirrors UNIT 5. LASER BEAM MACHINING, drilling, heat, machining, lasers, speeds, thermal energy, output power, thickness.

1) A number of different types of … are used in laser beam machining.

2) Laser beam machining uses a … to achieve precision in cutting and ….

3) Some lasers are capable of an … of 25,000 W.

4) In cutting applications, the laser beam may be "transmitted" and UNIT 5. LASER BEAM MACHINING "switched" by using … to manipulate the beam

5) Laser beam machining uses … to drill and cut with speed arid precision.

6) A 1250-W CO2 laser can cut mild steel at … ranging between 40 and 140 crrr/min.

7) At a … of 12 mm, the cut can be 40 enrr/min.

8) The most commonly used UNIT 5. LASER BEAM MACHINING lasers for … are Nd:YAG lasers.

9) The intensity of light produces a tremendous amount of … at the point of application to the workpiece.

10) Lasers may be operated in either pulsed or continuous-wave (CW) ….

Exercise 8. A.Find the synonyms to the following words and translate them:

Beam, workpiece, to machine UNIT 5. LASER BEAM MACHINING, energy, speed, amount, precision, flow, to duplicate, to operate, percussion, technology, varied.

B.Find the antonyms to the following words:

To heat, to melt, advantages, capable, single, high power, maximum pulse energy, to increase, traditional, frequently, mild steel.

Exercise 9.Compose several sentences, using the following words:

Types of lasers, laser UNIT 5. LASER BEAM MACHINING beam machining, to cut steel and other materials, with speed and precision, laser technologies, thermal energy, to drill and cut, to manipulate the beam, power output, new techniques.

Exercise 10. A.Remember the cases, where the infinitive is used without particle “to”:

· After modal verbs;

· After verbs “to let” and “to UNIT 5. LASER BEAM MACHINING make”;

· In Complex Object after the verbs of perception (to feel, to hear, to see, etc.);

· After expressions “I would rather…”, “You had better…”.

B.Now translate the following sentences, using infinitive with or without particle “to”:

1) Мы желали бы приобрести несколько лазерных станков этой компании.

2) Я в UNIT 5. LASER BEAM MACHINING первый раз увидел, как луч лазера убирает ненадобный материал.

3) Ты выглядишь вялым. Лучше бы ты окончил гравирование завтра.

4) Разреши посодействовать для тебя, и я с наслаждением расскажу о сферах внедрения лазера.

5) Думаю, я просто смогу научиться сверлить отверстия с помощью лазера.

6) Что принуждает тебя считать, как будто UNIT 5. LASER BEAM MACHINING лазерный луч можно использовать к керамике, кремнию и графиту?

7) Для тебя нужно уяснить, что лазер модели 1250-W CO2 может резать мягенькую сталь.

8) Я слышал, как представитель говорил, что даже липкие материалы не являются неувязкой для лазерного луча.

9) Я сделаю все вероятное, чтоб починить этот станок, и уже завтра вы можете UNIT 5. LASER BEAM MACHINING делать резку и сверление материала с прежней точностью.

10) Лазерным лучом можно «управлять» с помощью зеркала, или волоконно-оптических кабелей и тумблеров.

Exercise 11.Speak on the advantages of laser cutting and drilling. Use the information given below and the active vocabulary of the lesson.

A. Laser Drilling Advantages:

· Using laser system UNIT 5. LASER BEAM MACHINING software, the operator instantly can control hole shape and size to produce round, oval or rectangular holes, or any shape imaginable. This eliminates downtime due to tool changes.

· Very small holes can be laser drilled in production. A focused spot can be as small as 0.1mm (0.004") in diameter.

· Since UNIT 5. LASER BEAM MACHINING the tool is a beam of light, the tool never needs to be replaced eliminating downtime because of punch breakage.

B.Laser Cutting Advantages:

· There is almost no limit to the cutting path; the point can move in any direction unlike other processes that use knives or saws.

· The laser UNIT 5. LASER BEAM MACHINING beam is always sharp and can cut very hard or abrasive materials.

· Cutting with lasers is a very cost effective process with low operating and maintenance costs and maximum flexibility.

UNIT 6. PRESSES

Exercise 1. Match the proverbs with the meaning. Think of other Russian equivalents.

1) The busiest man finds UNIT 5. LASER BEAM MACHINING the most leisure.

2) Many hands make light work.

3) Many men, many minds.

4) Idle folks lack no excuses.

5) Idleness rusts the mind.

6) Money spent on the brain is never spent in vain.

1) Сколько голов, столько разумов

2) Самый занятой человек находит больше всего досуга.

3) Денек гуляет, два нездоровой, а на 3-ий UNIT 5. LASER BEAM MACHINING — выходной.

4) Когда рук много, работа спорится.

5) Средства, истраченные на образование, никогда даром не пропадают.

6) Праздность мозг притупляет. Труд человека кормит, а лень портит.

Exercise 2. Read new words and word combinations:

Machine press - пресс

Roller - крутящийся цилиндр, ролик, вал

Relief - рельеф

To emboss - чеканить, вытеснять

Aluminum foil - дюралевая фольга

To encompass - делать, производить

To coin - чеканить UNIT 5. LASER BEAM MACHINING; штамповать

Stamping - штемпелёвка

Scrap metal - железный лом, скрап

Pillar - столб, опора

To chuck - обрабатывать, зажав в патроне деталь либо инструмент

Hub – втулка

Clamp – тиски

Chuck – патрон, фиксатор

Swing – амплитуда

Throat distance – глубина зева

Sanding – шлифовка, чистка песком

Honing - обточка

Drawbar - сцепное приспособление

Exercise 3. Read and remember the names of presses:

Forge press - ковочный (штамповочный) пресс

Set of rollers - набор роликов

Set of plates – набор пластинок

Punch press - дыропробивной UNIT 5. LASER BEAM MACHINING пресс

Capping press – укупорочный пресс

Brake press - фрикционный пресс

Drill press – сверлильный станок

Exercise 4. Answer the questions:

1) What do you know about machine press?

2) How do you think it works?

3) What products of press machining can you find in everyday life?

Exercise 5.Read and translate the following text.

PRESSES

A press, or a UNIT 5. LASER BEAM MACHINING machine press is a tool used to work metal (typically steel) by changing its shape and internal structure.

A forge pressreforms the work piece into a three dimensional object—not only changing its visible shape but also the internal structure of the material. A stronger part results from this process than if UNIT 5. LASER BEAM MACHINING the object was machined.

Bending is a typical operation performed and occurs by a machine pressing, or applying direct pressure, to the material and forcing it to change shape. A press brake is a typical machine for this operation/

An easy to understand type of machine press is UNIT 5. LASER BEAM MACHINING a set of rollers. Metal is fed into the rollers, which are turning to pull the material through. The space between the rollers is smaller than the unfinished metal, and thus the metal is мейд thinner and/or wider.

Another kind of press is a set of plates with a relief, or UNIT 5. LASER BEAM MACHINING depth-based design, in them. The metal is placed between the plates, and the plates are pressed up against each other, deforming the metal in the desired fashion. This may be coining or embossing or forming. A punch press is used for forming holes. Capping Presses form caps from rolls of aluminium UNIT 5. LASER BEAM MACHINING foil at up to 660 per minute.

Progressive stamping is a manufacturing method that can encompass punching, coining, bending and several ways of modifying the metal, combined with an automatic feeding system. The feeding system pushes a coil of metal through all of the stations of a progressive UNIT 5. LASER BEAM MACHINING stamping die. Each station performs one or more operations until a finished part is мейд per the requirements on the print. The final operation is a cut-off operation, which separates the finished part from the carrying web. The carrying web, along with metal that is punched away in previous operations UNIT 5. LASER BEAM MACHINING, is considered scrap metal.

A brake press is a special type of machine press that bends sheet metal into shape.

Adrill press (also known as pedestal drill, pillar drill, or bench drill) is a fixed style of drill that may be mounted on a stand or bolted to the UNIT 5. LASER BEAM MACHINING floor or workbench. A drill press consists of a base, column (or pillar), table, spindle (or quill), and drill head, usually driven by an induction motor. The head has a set of handles (usually 3) radiating from a central hub that, when turned, move the spindle and chuck vertically, parallel UNIT 5. LASER BEAM MACHINING to the axis of the column. The table can be adjusted vertically and is generally moved by a rack and pinion. The size of a drill press is typically measured in terms of swing. Swing is defined as twice the throat distance, which is the distance from the center UNIT 5. LASER BEAM MACHINING of the spindle to the closest edge of the pillar. A drill press has a number of advantages over a hand-held drill:

· less effort is required to apply the drill to the workpiece. The movement of the chuck and spindle is by a lever working on a rack and pinion, which UNIT 5. LASER BEAM MACHINING gives the operator considerable mechanical advantage.

· the table allows a vise or clamp to position and lock the work in place making the operation much more secure.

· the angle of the spindle is fixed in relation to the table, allowing holes to be drilled accurately and UNIT 5. LASER BEAM MACHINING repetitively.

· Speed change is achieved by manually moving a belt across a stepped pulley arrangement. Some drill presses add a third stepped pulley to increase the speed range. Modern drill presses can, however, use a variable-speed motor in conjunction with the stepped-pulley system; a few older drill presses, on UNIT 5. LASER BEAM MACHINING the other хэнд, have a sort of traction-based continuously variable transmission for wide ranges of chuck speeds instead, which can be changed while the machine is running.

· Drill presses are often used for miscellaneous workshop tasks such as sanding, honing or polishing, by mounting sanding drums, honing wheels and UNIT 5. LASER BEAM MACHINING various other rotating accessories in the chuck. This can be dangerous on many presses, where the chuck arbor is held in the spindle purely by the friction of a Morse taper instead of being held securely by a drawbar.

Exercise 6.Answer the questions to the text, using UNIT 5. LASER BEAM MACHINING the active vocabulary of the lesson.

1) What is a press?

2) What types of machine press do you know?

3) What is bending?

4) What kind of press is used for forming holes?

5) What is progressive stamping? What does this method encompass?

6) What is a drill press?

7) What does a drill press UNIT 5. LASER BEAM MACHINING consist of?

8) What are the advantages of a drill press over a hand-held drill?

9) How can be speed change achieved?

10) What are drill presses often used for?

Exercise 7. Translate orally, and make it fast:

Изменять форму и внутреннюю структуру, ковочный пресс, bending, подавать металл к роликам, необработанный UNIT 5. LASER BEAM MACHINING металл, a set of plates, embossing, чеканить, a punch press, a capping press, дюралевая фольга, feeding system, штемпелевка, a cut-off operation, железный лом, sheet metal, фрикционный пресс, a drill press, амплитуда, шпиндель, a chuck, барабан для чистки песком, honing wheel, трение, a drawbar.

Exercise 8.Which word doesn’t UNIT 5. LASER BEAM MACHINING match the whole line?

1) plasma arc, drill press, electron beam, laser.

2) to vaporize, to machine, to process, to work.

3) metal, plate, aluminum, steel.

4) spindle, clamp, chuck, relief.

5) sanding, honing, milling, polishing.

Exercise 9.A typical manual drill press is shown in the figure below. Study the parts of it.

Exercise 10.And UNIT 5. LASER BEAM MACHINING now try to find out which parts of the drill press perform the following operations?

1) Moves the drill head up and down.

2) Locks the movement of the drill head.

3) Maintain a specific length of travel.

4) Let the operator know where he is vertically.

5) Can move vertically and rotate about the UNIT 5. LASER BEAM MACHINING vertical guide post.

6) Powers the drill.

7) Can be adjusted vertically and is generally moved by a rack and pinion.

Exercise 11.Replace the noun clause by gerund with preposition “of”. Translate the sentences into Russian:

Model:He thought he would change the shape of the metal by press machining UNIT 5. LASER BEAM MACHINING. - He thought of changing the shape of the metal by press machining.

1) I’m thinking that I shall use a set of rollers to make this metal sheet thinner.

2) I hear there are some new drill pressers at your workshop. So do you think you will be able to make the UNIT 5. LASER BEAM MACHINING whole retooling?

3) I think I shall polish and hone this workpiece tomorrow.

4) What do you think you will do today at work? – I thought I would check the operation abilities of the brake press.

5) We think we’ll deliver a pillar drill today at 6 o’clock. Is that convenient for you?

6) The manufacturers UNIT 5. LASER BEAM MACHINING think they will widen the field of application of presses in the nearest future.

Exercise 12.Read the text “Presses” one more time and make the summary of it.


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