2. Machining is very important for our industry because 4/5
(four fifths) of all manufactured parts should be machined.
3. But this traditional classification does not help explain how machine tools work.
4.To obtain a good surface finish the workpiece should be geometrically oriented with the movements of the cutting edge.
5. Machine tools are best described by how the workpiece is held and what the relative movements are between the part and the tool.
6. Machining is performed by special power-driven devices called machine-tools.
Завдання 9. Розбийте текст на смислові частини та дайте назву кожній з них.
Завдання 10. Дайте заголовок до тексту.
Завдання 11. Напишіть стислу (5-6 речень) анотацію тексту 7А.
Завдання 12; Випишіть з тексту речення позначені (*).
Завдання 13. Перекладіть подані нижче фрагменти речень, звертаючи увагу на модальні дієслова та пасивну форму присудка:
Parts must be machined, before they are completed……; these parts should be designed so that they can be machined easily and economically...; how to design parts that can be machined easily...; how easily a surface can be machined....; how well the surface can be matched to the movements of the machine….; the workpiece must have locating surfaces... .
Завдання 14. Складіть схему класифікації металообробних верстатів. Зробіть усне повідомлення, користуючись цією схемою.
Завдання 15. Прочитайте та перекладіть текст 7Б, користуючись словником.
TEXT 7Б
Many machine tools generate shapes with simple linear movement. Basically, they use cutting tools to saw or slit; to machine flat, square, or parallel surfaces: or to generate long, linear forms such as keyways, splines, or channels.
Milling machines are the most common metal-cutting machine tools in the category. During milling a horizontally rotating hardened toothed cutter shears large amounts of metal from its path as the part passes by on a moving worktable.
Surface grinding machines are often used to generate flat or linear surfaces on closely toleranced parts and to cut hardened or hard-to-machine metals. In most machines, the workpiece reciprocates bасk and forth while the spinning grinding wheel slowly drops down on the workpiece surface.
Most precision-machined surfaces are surfaces of rotation. Bearings, shafts, pistons, and cylinders, for example, are all surfaces generated by rotating the workpiece about an axis and applying a grinding wheel or a cutting tool. Under these conditions, the generated surface is always concentric about the axis of rotation. Common machine tools of this type include the diverse lathe family (including the vertical boring mill), and cylindrical grinding machines.
In general, machines in this group can perform any of three operations. They can move a cutting tool parallel to the axis of rotation (as when single-point turning or grinding a diameter for example). They can move a cutting tool radially into the part . (as when forming a diameter or when removing metal from the end of a part-commonly called "facing"). Or they can move the cutting tool into the face of the part along the axis of rotation.
Any metal cutting machine that rotates the workpiece and applies a forming or single-point tool to the surface to be machined is a "turning machine". The basic turning machine - and probably the oldest precision metalworking machine tool - is the lathe. Until the advent of the cylindrical grinder, lathe turning was the most accurate metalworking process available. Production cylindrical grinding, however, is usually ten times more accurate and repeatable than most turning operations.
Завдання 16. Прочитайте та дайте українські еквіваленти поданих нижче слів та словосполучень:
а) Keyway, spline, channel, path, shaft, face, facing;
б) horizontally rotating; toothed cutter; a moving worktable; surface grinding machine; closely toleranced parts; to reciprocate back and forth; spinning grinding wheel; vertical boring mill; precision-machined surfaces; cylindrical grinding machine; forming tool; single-point tool; production cylindrical grinding; accurate metalworking process; axis of rotation.
Завдання 17. Перекладіть такі фрагменти речень, звертаючи увагу на не особові форми дієслова:
…..they use cutting tools to generate long linear forms;…..surfaces generated by rotating the workpiece about an axis and applying a grinding wheel or a cutting tool;. .....including the vertical boring mill;.....as when forming a diameter or when removing metal from the end of a part...; …... the surface to be machined.
Завдання 18.Дайте відповіді на такі запитання:
1. What are the two major types of surfaces?
2. What machines are used to generate linear surfaces?
3. What is the peculiarity of processing surfaces of rotation?
4. What are the common machine tools used to generate surfaces of rotation?
5. What are the three operations performed by these machines?
6. What is the oldest precision metalworking machine tool?
7. What can you say if you compare lathes and cylindrical grinders?
Завдання 19.Прочитайте зміст тексту схематично.
Завдання 20: Розділіть подані нижче речення в порядку розгортання їх теми:
1. Forming is a fast way to generate intricate shapes on a workpiece, but the forming tool may be costly.
2. Machine tools generate surfaces in two ways: either by "forming" or by feeding the cutting tool in and out along the length of the part.
3. A tool with a notch (паз) in its cutting edge for example, generates a raised rib on the workpiece.
4. Forming, then, transfers the exact shape of the tool to the workpiece in one tool movement.
5. Either concept can be applied to grinding, turning, milling, and other common machining processes.
6. Tools for forming are specially ground to reflect the shape of the finished part.
7. And as the forming cutter wears down unevenly, the shape generated on the part may change.
Завдання 21. Передайте зміст тексту рідною мовою.
Завдання 22. Зробіть переказ.
УРОК 8
Завдання 1. Уважно прочитайте подані нижче слова та їх переклад, запам'ятайте їх значення.
self - само-себе
to explain - пояснювати
honing – хонінгування
blade - лезо, клинок
to vary - різнитися, змінюватися
straight [streit] - прямий
bent - зігнутий
offset - зміщення
to reach - діставати, досягати
solid - твердий .
insert- вставка
to attach - прикріплювати
to sinter - спікати(ся)
to fasten - прикріпляти
shank - хвостовик
groove - жолобок, виїмка, паз
stock - запас, матеріал
to break (broke, broкen) - ламати (ся), .зламувати
curl - локон, звивина
to manage - управляти, справлятися
to dispose (of) - розпоряджатися
to secure - укріпляти
to contribute (to) - сприяти (чомусь), робити внесок
slab - плоска заготовка
helical - спіральний
whilst - поки, доки, тоді як
layer – шар
tapping - нарізка, різьблення мітчиком
thread - різь, нарізка
to cause - завдавати, спричиняти
Завдання 2. Прочитайте та перекладіть такі слова та словосполучення:
а) to adapt, to intend, series, term;
б) sharp - to sharpen; cutting tip = cutting edge;
в) multi-point tool; honing stone: cutting action; area of machining; high-quality steel; sintered carbide; self-explanatory term; chipbreaker; twist drill; slab milling cutter; complicated action; broaching tool; tool shank; helical broach; gradually increasing thickness; workpiece (worn) material; desired thread shape; relative motion.
Завдання 3. Уважно прочитайте текст 8А. Спробуйте: якомога точніше та повніше зрозуміти його зміст:
TEXT 8А
Practical cutting tools mаy be divided into two categories: (1) single-point tools; (2) multi-point tools. These terms are self-explanatory.
Single-or multiple-point cutting tools, including broaching tools, milling cutters, honing stones, abrasives, and saw blades, are common forms of cutting devices. Although varied in configuration, the basic cutting action performed by each is much the same.
Single-point tools vary, in design, each adapted to the operation for which it is intended. The tool may be straight, bent, offset, or have some other special form that will enable its cutting tip to reach the desired area of machining. The tool may be made from one solid piece of tool steel with the cutting edge round on the end, or it may have an insert or tip attached to it to provide a harder cutting surface. The insert may be a piece of high-quality tool steel or a special material such as sintered carbide and be brazed, welded, or fastened to the tool shank by mechanical means.
Tools may be sharpened or shaped by grinding, and inserts may be replaced or rotated when chipped or worn. Frequently a groove or irregularity is ground in the face of the tool behind the cutting edge. This groove, called a chipbreaker, causes removed stock to manage into chips or small curls, thus becoming easier manage or to dispose of.
Any multi-point cutting tool can be regarded as a series of two or more single-point cutting tools secured to a common body. The relative motion between workpiece and tool is such that each tool point contributes to the removal of workpiece material. For example, a twist drill mar be regarded as two single-point cutting tools fixed to а common shank which is rotated about its axis. As the drill is fed in a direction parallel to its axis each cutting edge should remove an equal share of the work material.
The slab milling cutter also has a rather complicated action. Here the cutter, which has a number of lone helical cutting edges, is rotated whilst the workpiece is fed past the cutter. Each cutting edge removes a layer of material of gradually increasing thickness.
A broach is a further example of a multipoint tool. In broaching the tool is forced past the workpiece at low speed and each broach tooth removes a small layer of the work material.
A process similar to that of broaching is the tapping process. Here the tap, which at its lower and may be likened to a helical broach, is fed and rotated into a prepared hole. Each cut tine edge removes a small layer of metal to form the desired thread shape.
Завдання 4. Визначте, які з поданих нижче речень містять додаткову до тексту 8А інформацію:
1. a multi-point cutting tool can always be regarded as several single-point tools Joined together and constrained to move in such a way that each individual tool contributes to the process of metal removal.
2. Single-point tools consist usually of a piece of material of rectangular section caned the shank on one edge of' which are ground the faces and flanks which, intersect to form the cutting edges.
3. The tool and the workpiece are held in the machine tool in such a way that when the appropriate motions are applied be the machine, the tool point (i.e. the end of the tool on which the cutting edges are formed) generates the desired shape of the workpiece.
4. A second type of cutting device commonly used on such power tool as milling machines, horizontal boring machines, etc. is the revolving multitoothed cutter.
5. Multipoint cutters are made in many destine, each to perform efficiently a certain operation.
Завдання 5. Користуючись текстом 8А та завданням 4, дайте відповіді ва запитання:
1. In what way are practical cutting tools classified?
2. What is the difference between a single-point tool and a multipoint tool?
3. What is the tool point?
4. Why are single-point tools of various forms?
5. What is the aim of us me inserts?
6. What is a chipbreaker?
Завдання 6. Випишіть з тексту ключові слова.
Завдання 7. Випишіть з тексту речення, позначені-зірочкою (*). Перекладіть, їх.
Завдання 8. Розбийте текст на частини та дайте назву кожній з них.
Завдання 9. Перекажіть текст за складеним планом, користуючись ключовими словами.
Завдання І0. Прочитайте та перекладіть текст 8Б користуючись словником.
TEXT 8Б
A variety of materials is used to meet the many requirements :of the metal-cutting industries, carbon steel tools having low initial cost are used to machine the light metals, or free cutting steels, with light cuts at low speeds. They retain their hardness up to temperatures of 400 F. High-speed steel tools of many types the work-horses of industry. Their cost is several times that carbon steel tools, but they permit, cut tine speeds about twice those of carbon steel and withstand temperatures up to 1000 F*. Tungsten-base and molybdenum-base high speed steels, each having chromium and vanadium and sometimes cobalt and other metals added, fill special requirements*.
Tools of sintered carbide are still more expensive than those of high-speed steel*. They have greater hardness with working -temperature limits up to 1800 F. Tools of this kind will machine steels of average hardness 4-8 times as those of high-speed steel*.They will machine very hard metals satisfactorily. Being less ductile than the tool steels, they must be carefully designed and supported to prevent chipping or fracture. Because of their high cost they are used as tips, small formed pieces which are brazed or clamped into rigid steel shanks. Present practice in high quantity production is to use small, thin, indexible tips of triangular, square, or circular profile, clamped to strong shanks. When the cutting points on both faces are worn, the tip is thrown away rather than resharpened. This reduces or eliminates the expensive diamond-wheel grinding.
Industrial diamonds are also used to machine metals at light cuts and high speeds up to 100 ft/min and produce high dimensional accuracy and superior surface finish. Ceramic materials, called cermets and cemented oxides, permit high cutting speeds (1000-15.000 ft/min) with light cuts, speeds of 1000-3000 ft/min are more practical for the thin indexing, throw-away types.
Завдання 11. Прочитайте та перекладіть рідною мовою такі слова та словосполучення:
a) to retain, to prevent, chipping, to clamp, trianguiar, cermet (ceramal), cemented, to resharpen;
6) initial cost; freecutting steel: work-horses of industry; to withstand temperatures up to 1000 F; rigid, steel shank; tungsten-base high-speed-steel; working temperature limits; circular profile; diamond wheel grinding industrial diamonds; cemented oxides; high dimensional accuracy; thin indexing throwaway types! to meet the requirements; high
quantity production.
Завдання 12. Розставте речення таким чином, щоб отримати переказ
тексту.
1. Tools of sintered carbide machine very hard metals satisfactorily, but because of their high cost they are usually used as tips.
2. A number of materials are used to meet the requirements of the metal cutting industries.
З. Though high-speed steel tools are much more expensive than carbon steel tools they are the work-horses of -industry as they permit high cutting speeds and withstand high temperatures.
4. Industrial diamonds provide superior surface finish and, high dimensional accuracy at light cuts and high speeds.
5. Besides all these materials there are some ceramic materials, called cermets, used to machine metals.
6. Carbon steel tools are very cheap and are used to machine the light metals at low speeds and comparatively low temperatures.
Завдання І3. Визначте, чи відповідають змісту тексту такі твердження:
1. Carbon steel tools retain their hardness up to temperatures of 1000 F.
2. High-speed steel tools permit cutting speeds al out twice those of carbon steels and are very cheap.
3. Tools of sintered carbide permit very high cutting speeds. Sintered carbide tips are usually resharpened when then cutting points are worn.
5. Industrial diamonds permit to produce high dimensional accuracy.
Завдання І4. Виправте хибні твердження із завдання І3
Завдання 15. Дайте заголовок до тексту 8Б.
Завдання 16. Перекладіть речення, позначені в тексті зірочкою звертаючи особливу увагу на виділені їх частини.
Завдання 17. Користуючись даною схемою, розкажіть про використання різних матеріалів для виготовлення металорізальних інструментів:
Cutting tool materials:
Metals: Non-ferrous – Satellites.
Ferrous: High steel – carbon – high speed steel.
Non-metals: Metallic carbides - Aluminium oxides - Diamond
Завдання 18. використовуючи тексти уроку, підготуйте письмове повідомлення на тему "Типи металорізальних інструментів та матеріали, які використовуються для їх виготовлення" (обсяг - 10 тис. знаків).
УРОК 9
«Взаємозв'язок між величиною основних кутів різання, строком служби інструменту та якістю обробки".
Завдання 1. Уважно прочитайте подані нижче олова та їх переклад. запам'ятайте їх значення:
steady - стійкий, постійний
state - стан
friction - тертя
presence - присутність, наявність
to lead (to) - призводити (до)
to build up - наварювати, наплавляти
pile - нагромадження
severe - суворий
to occur - траплятися, зустрічатися
tо carry away - відносити, захоплювати
Завдання 2. Прочитайте та перекладіть групи слів, доповніть таблицю словотворчих елементів:
continuous - discontinuous;
table - unstable;
side – underside;
to go – to undergo.
Завдання 3. Дайте-українські еквіваленти таких словосполучень. Прочитайте їх:
Cutting conditions; continuous chip: discontinuous chip formation; mild steel; under these conditions; a “steady state” process; under some conditions; welds itself to the tool face; layer upon layer; the resulting pile of material; a built-up edge; one of the principal factors; to undergo severe strain; primary deformation zone; high rates of feed.
Завдання4. Уважно прочитайте текст 9А. Постарайтеся якомога точніше та повніше зрозуміти його зміст:
TEXT 9А
The type of chip produced during metal cutting depends on the material being machined and the cutting conditions used. Continuous chip is common when machining most ductile materials such as wrought iron, mild steel, copper and aluminum. Cutting under these conditions is a "steady state" process.