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контрольная работа: 1. Read the text. Honing Honing is an abrasive machining process that produces a precision surface on a metal workpiece by scrubbing an abrasive stone against it along a controlled path. Honing is primarily used to improve the geometric form of a surface, but may also improve the surface texture. 2. Give Russian equivalents to the following word combinations. 1. Oscillate axially 2. Bore honing 3. Honing stone. 3. Match the synonyms. 1. stiff 2. compliant 3. average. 4. Match English and Russian equivalents. 1. gag 2. to improve 3. precision. 5. Match the words with the
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Контрольная работа №4 (профсфера)
Контрольная работа №4
1. Read the text.
Honing
Honing is an abrasive machining process that produces a precision surface on a metal workpiece by scrubbing an abrasive stone against it along a controlled path. Honing is primarily used to improve the geometric form of a surface, but may also improve the surface texture.
Typical applications are the finishing of cylinders for internal combustion engines, air bearing spindles and gears. Types of hone are many and various but all consist of one or more abrasive stones that are held under pressure against the surface they are working on. In everyday use, honing steel is used to hone knives, especially kitchen knives, and is a fine process, there contrasted with more abrasive sharpening.
Other similar processes are lapping and super finishing. Honing uses a special tool, called a honing stone or a hone, to achieve a precision surface. The hone is a composed of abrasive grains that are bound together with an adhesive. Generally, honing grains are irregularly shaped and about 10 to 50 micrometers in diameter. Smaller grain sizes produce a smoother surface on the workpiece.
A honing stone is similar to a grinding wheel in many ways, but honing stones are usually more friable so that they conform to the shape of the workpiece as they wear in. To counteract their friability, honing stones may be treated with wax or sulfur to improve life; wax is usually preferred for environmental reasons.
Any abrasive material may be used to create a honing stone, but the most commonly used are corundum, silicon carbide, cubic boron nitride, or diamond. The choice of abrasive material is usually driven by the characteristics of the workpiece material. In most cases, corundum or silicon carbide are acceptable, but extremely hard workpiece materials must be honed using super abrasives. The hone is usually turned in the bore while being moved in and out. Special cutting fluids are used to give a smooth cutting action and to remove the material that has been abraded. Machines can be portable, simple manual machines, or fully automatic with gauging depending on the application.
Modern advances in abrasives have made it possible to remove much larger amount of material than was previously possible. This has displaced grinding in many applications where "through machining" is possible. External hones perform the same function on shafts.
Since honing stones look similar to grinding wheels, it is tempting to think of honing as a form of low-stock removal grinding. Instead, it is better to think of it as a self-truing grinding process.
In grinding, the wheel follows a simple path. For example, in plunge grinding a shaft, the wheel moves in towards the axis of the part, grinds it, and then moves back out. Since each slice of the wheel repeatedly contacts the same slice of the workpiece, any inaccuracies in the geometric shape of the grinding wheel will be transferred onto the part. Therefore, the accuracy of the finished workpiece geometry is limited to the accuracy of the truing dresser. The accuracy becomes even worse as the grind wheel wears, so truing must occur periodically to reshape it.
The limitation on geometric accuracy is overcome in honing because the honing stone follows a complex path. In bore honing for example, the stone moves along two paths simultaneously. The stones are pressed radially outward to enlarge the hole while they simultaneously oscillate axially. Due to the oscillation, each slice of the honing stones touch a large area of the workpiece. Therefore, imperfections in the honing stone's profile cannot transfer to the bore. Instead both the bore and the honing stones conform to the average shape of the honing stones' motion, which in the case of bore honing is a cylinder. This averaging effect occurs in all honing processes; both the workpiece and stones erode until they conform to the average shape of the stones' cutting surface. Since the honing stones tend to erode towards a desired geometric shape, there is no need to true them. As a result of the averaging effect, the accuracy of a honed component often exceeds the accuracy of the machine tool that created it.
The path of the stone is not the only difference between grinding and honing machines; they also differ in the stiffness of their construction. Honing machines are much more compliant than grinders. The purpose of grinding is to achieve a tight size tolerance. To do this, the grinding wheel must be moved to an exact position relative to the workpiece. Therefore a grinding machine must be very stiff and its axes must move with very high precision.
A honing machine is relatively inaccurate and compliant. Instead of relying on the accuracy of the machine tool, it relies on the averaging effect between the stone and the workpiece. In fact, compliance is a requirement of a honing machine that is necessary for the averaging effect to occur. This leads to an obvious difference between the two machines: in a grinder the stone is rigidly attached to a slide, while in honing the stone is actuated with pneumatic or hydraulic pressure.
High-precision workpieces are usually ground and then honed. Grinding determines the size, and honing improves the shape.
The difference between honing and grinding is not always distinct. Some grinders have complex movements and are self-truing, and some honing machines are equipped with in-process gaging for size control. Many through-feed grinding operations rely on the same averaging effect as honing.
2. Give Russian equivalents to the following word combinations.
1. Oscillate axially
2. Bore honing
3. Honing stone
4. Truing dresser
5. Grind wheel
6. Cutting fluids
7. Silicon carbide
8. Abrasive grains
9. Internal combustion engines
10. Air bearing spindles
3. Match the synonyms.
1. stiff
2. compliant
3. average
4. imperfection
5. smooth
6. to counteract
7. to scrub
a. oppose, object
b. even
c. customary, usual
d. rub
e. susceptible
f. rigid
g. defect
4. Match English and Russian equivalents.
1. gag
2. to improve
3. precision
4. compliant
5. honing stone
6. to counteract
7. stiff
a. точность; чёткость
b. точильныйкамень
c. податливый
d. заглушка, пробка
e. препятствовать
f. улучшать; совершенствовать
g. Негибкий
5. Match the words with their definitions.
1. friability
2. gage
3. to improve
4. to consist
5. to treat with
6. to counteract
7. remove
8. to exceed
9. to oscillate
10. to follow
a. achieve or produce something better than
b. is the ability of a solid substance to be reduced to smaller pieces with little effort
c. is used to make measurements
d. take (something) away or off from the position occupied
e. be composed or made up of
f. act against (something) in order to reduce its force or neutralize it
g. apply a process or a substance to (something) to protect or preserve it or to give it particular properties
h. vary in magnitude or position in a regular manner about a central point(of a circuit or device) cause the electric current or voltage running through it to behave in this way
i. surpass go in the same direction as or parallel to (another)
j. be better than;
6. Put the verbs given to complete the sentences. Translate them.
Improved; consists; does not conform; scrub; to counteract; were treated; follows; exceeded; removed
1. _____________ the walls down well before painting them.
2. He ______________ his German.
3. The crew ______________ of five men.
4. The kitchen _______________to hygiene regulations.
5. Should we deliberately intervene in the climate system ________________ global warming?
6. The lawns _______________ with weedkiller every year.
7. Customs officials ______________ documents from the premises.
8. The road ____________ the track of the railway line.
9. Economic growth ______________ expectations this year.
7. Fill in the gaps using the information from the text. Translate the sentences.
1. Honing is an _______________ machining process that produces a precision surface on a metal workpiece.
2. A honing machine is relatively inaccurate and relies on the ________________ effect between the stone and the workpiece.
3. Honing stones look similar to grinding wheels and can be considered as a form of ________________ removal grinding.
4. A grinding machine is very stiff and its axes move with very high _______________.
5. The limitation on geometric accuracy is overcome in _______________ because the honing stone follows a complex path.
6. Honing stones are usually more _______________ comparing with a grinding wheel so they conform to the shape of the workpiece as they wear in.
7. The most common abrasive materials that are used to create a ____________ __________ are corundum, silicon carbide, cubic boron nitride, or diamond.
8. Decide whether the following statements are true [T] or false [F] in relation to the information in the text. If you feel a statement is false, change it to make it true. Translate them.
1. Honing is primarily used to improve the geometric form of a surface, but never to improve the surface texture.
2. Types of hone are many and various but all consist of two or more abrasive stones that are held under pressure against the surface they are working on.
3. The hone is a composed of abrasive grains that are bound together with an adhesive.
4. A honing stone is similar to a grinding wheel in many ways, but honing stones are usually not so friable.
5. The limitation on geometric accuracy is overcome in honing because the honing stone follows a simple path.
6. A grinding machine is relatively inaccurate and compliant.
9. Make sentences from the words given, translate.
1. The of grinding purpose achieve a is to size tight tolerance.
2. Honing are compliant than much more machines grinders.
3. Honing usually more stones are friable.
4. used Honing is in of internal production engines combustion.
5. A grinding inaccurate machine is and compliant.
10. Translate into Russian.
1. Honing is a high precision process, it is also relatively expensive. Therefore it is only used in components that demand the highest level of precision. It is typically the last manufacturing operation before the part is shipped to a customer. The dimensional size of the object is established by preceding operations, the last of which is usually grinding. Then the part is honed to improve a form characteristic such as roundness, flatness, cylindricity, or sphericity.
2. Since honing is a relatively expensive manufacturing process, it can only be economically justified for applications that require very good form accuracy. The improved shape after honing may result in a quieter running or higher precision component.
3. Any abrasive material may be used to create a honing stone, but the most commonly used are corundum, silicon carbide, cubic boron nitride, or diamond. The choice of abrasive material is usually driven by the characteristics of the workpiece material. In most cases, corundum or silicon carbide are acceptable, but extremely hard workpiece materials must be honed using super abrasives.
4. Typical applications are the finishing of cylinders for internal combustion engines, air bearing spindles and gears. Types of hone are many and various but all consist of one or more abrasive stones that are held under pressure against the surface they are working on.
11. Translate into English.
Хонингование — вид абразивной обработки материалов с применением хонинговальных головок (хонгов). В основном применяется для обработки внутренних цилиндрических отверстий путём совмещения вращательного и поступательно-возвратного движения хона с закреплёнными на нём раздвижными абразивными брусками с обильным орошением обрабатываемой поверхности смазочно-охлаждающей жидкостью. Один из видов чистовых и отделочных обработок резанием.
Хонингование наружных поверхностей осуществляется на специализированных станках (горизонтально-хонинговальных) или модернизированных (шлифовальных, горизонтально-расточных), производительность при этом по сравнению с суперфинишированием в 2—4 раза выше вследствие бо́льшего количества брусков и бо́льших давлений.
Хонингование используется при обработке отверстий в различных деталях в том числе в деталях двигателя (отверстий блоков цилиндров, гильз цилиндров, отверстий кривошипной и поршневой головок шатунов, отверстий шестерен) и т.д. При обработке хонингованием обеспечивается стабильное получение точных отверстий и требуемых параметров шероховатости обработанной поверхности.
Особенностью хонингования является поступательно-возвратное движение хона с постоянным давленим бруска или постоянной скоростью радиальной подачи.
При обработке деталей из стали и чугуна применяют керосин или смесь керосина с веретённым маслом (10 %—20 %). При использовании алмазных хонинговальных брусков часто применяют в качестве смазочно-охлаждающей жидкости для хонингования обычную воду, в которую добавляют различные синтетические вещества, предотвращающие коррозию обрабатываемой детали и самого станка. Использование водных растворов оправдывается более высокой плотностью воды (по сравнению с маслами и керосином), а, следовательно, и более интенсивным отводом тепла, что является одним из важнейших требований предъявляемых к СОЖ. При этом водные растворы более экологичны и менее вредны для оператора станка.
12. Make a short summary about Honing, base on the following plan:
1. What is horning?
2. The principle of working.
3. The difference between horning and grinding.
