The milling machine's table, alternative, coolant, three phase power, assures, miscellaneous, transmission, a belt, the spindle's axis, a central hub, a stand

Speaking

Exercise 7. Answer the questions:

1) What does a drill press consist of?

2) How is the size of a drill press measured?

3) What are the advantages of a drill press?

4) How is speed change achieved?

5) What for are drill presses used?

6) What is a geared head drill press?

7) What is a radial arm drill press?

8) What are mill drills?

Exercise 8 . Read the text one more, define the main features of a geared head drill press, a radial arm drill pres and a mill drill (work in pairs).

 

Exercise 9. Write your own composition on the topic “Drilling Machines”, retell it then orally.

Section II. Lathe

Grammar: Infinitive.

Speaking: Lathe.

Lathe

Study vocabulary:

lathe [leið] – токарный станок circular cross-section ['sә:kjula] – круглое поперечное сечение surface ['sə:fis] – поверхность stationary – неподвижный, стационарный sideways ['saidweiz] – в сторону to enable – давать возможность knurling – накатка; насечка

variety [va'raiəti] – разнообразие, разновидность depth [depӨ] – глубина headstock ['hedstok] – передняя бабка spindle [spindl] – шпиндель chuck – зажим, патрон faceplate – планшайба lathe bed – станина станка tolerance – допуск

 

 

Exercise 1 . Read the following words and wordcombinations, give the Russian equivalents, remember them:

bed; headstock; tailstock; carriage; thread cutting mechanism; feeding mechanism; casting; support; align; slide; locate; carry; bearing; obtain; shaft; hollow; bore; taper; insert; thread; nose; move; graduate; measure; contain; either.....or; both.....and; apron; engage; saddle; ways.

 

Exercise 2 . Read the attributive groups, translate them into Russian:

thread cutting mechanism; feeding mechanism; gearing mechanism; sliding elements; live centre; dead centre; taper bore; hollow shaft; spindle speeds; face plate; left hand side; right hand side; at any point; to any point; to provide the bearing; outer end; to be of hollow construction; to be locked; feed rod; lead screw; cross slide; tool holder; thread cutting; change gears; gear box.

A lathe from 1911 showing component parts.
a = bed, b = toolrest, c = headstock, d = gear train to drive automatic screw shaft, e = pullies for belt drive from an external power source, f = spindle, g = tailstock. h = automatic screw shaft.

Lathe

Text: Lathe

Read and the text, write out the sentences with the Infinitive, translate them.

Brief Introduction

A lathe (pronounced /ˈleɪð/) is a machine tool which spins a block of material to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.

Lathes are used in woodturning, metalworking, metal spinning, and glassworking. Lathes can be used to shape pottery, the best-known design being the potter's wheel. Most suitably equipped metalworking lathes can also be used to produce most solids of revolution, plane surfaces and screw threads or helices. Ornamental lathes can produce three-dimensional solids of incredible complexity. The material is held in place by either one or two centers, at least one of which can be moved horizontally to accommodate varying material lengths. Examples of objects that can be produced on a lathe include candlestick holders, cue sticks, table legs, bowls, baseball bats, musical instruments (especially woodwind instruments), crankshafts and camshafts.

Lathe

Lathe is still the most important machine-tool. It produces parts of circular cross-section by turning the workpiece on its axis and cutting its surface with a sharp stationary tool. The tool may be moved sideways to produce a cylindrical part and moved towards the workpiece to control the depth of cut. Nowadays all lathes are power-driven by electric motors. That allows continuous rotation of the workpiece at a variety of speeds. The modern lathe is driven by means of a headstock supporting a hollow spindle on accurate bearings and carrying either a chuck or a faceplate, to which the workpiece is clamped. The movement of the tool, both along the lathe bed and at right angle to it, can be accurately controlled, so enabling a part to be machined to close tolerances. Modern lathes are often under numerical control.

Exercise 3. Find English equivalents in the text:

1) обрабатываемый материал 2) электропривод 3) более точный 4) отдельные детали 5) процесс массового производства 6) приспособления для держания резца и детали 7) операции по механической обработке детали 8) высоковольтный разряд

8) сверление ультразвуком 9) резание с помощью лазерного луча 10) гибкие производственные системы 11) детали круглого сечения 12) поворачивать деталь вокруг ее оси 13) двигать в сторону, двигать по направлению к детали 14) глубина резания 15) непрерывное вращение детали

Exercise 4. Translate into English:

1) Токарный станок позволяет производить детали круглого сечения.

2) Деталь зажимается в патроне или на планшайбе токарного станка.

3) Резец может двигаться как вдоль станины, так и под прямым углом к ней.

4) Современные токарные станки часто имеют цифровое управление.

 

Speaking

Exercise 5. Answer the questions:

1) What are machine-tools used for?

2) How are most machine-tools driven nowadays?

3) What facilities have all machine-tools?

4) How are the cutting tool and the workpiece cooled during machining?

5) What other machining methods have been developed lately?

6) What systems are used now for the manufacture of a range of products without the use of manual labour?

7) What parts can be made with lathes?

8) How can the cutting tool be moved on a lathe?

9) How is the workpiece clamped in a lathe?

10) Can we change the speeds of workpiece rotation in a lathe?

11) What is numerical control of machine tools used for?

 

Exercise 6. Read the following text, discuss in pairs the technical characteristics of metalworking lathes.

Metalworking lathes

A metalworking lathe

In a metalworking lathe, metal is removed from the workpiece using a hardened cutting tool, which is usually fixed to a solid moveable mounting called the "toolpost", which is then moved against the workpiece using handwheels and/or computer controlled motors. These (cutting) tools come in a wide range of sizes and shapes depending upon their application. Some common styles are diamond, round, square and triangular.

The toolpost is operated by leadscrews that can accurately position the tool in a variety of planes. The toolpost may be driven manually or automatically to produce the roughing and finishing cuts required to turn the workpiece to the desired shape and dimensions, or for cutting threads, worm gears, etc. Cutting fluid may also be pumped to the cutting site to provide cooling, lubrication and clearing of swarf from the workpiece. Some lathes may be operated under control of a computer for mass production of parts (see "Computer Numerical Control").

Metalworking lathes are commonly provided with a variable ratio gear train to drive the main leadscrew. This enables different pitches of threads to be cut. Some older gear trains are changed manually by using interchangeable gears with various numbers of teeth, while more modern or elaborate lathes have a quick change box to provide commonly used ratios by the operation of a lever.

The threads that can be cut are, in some ways, determined by the pitch of the leadscrew: A lathe with a metric leadscrew will readily cut metric threads (including BA), while one with an imperial leadscrew will readily cut imperial unit based threads such as BSW or UTS (UNF,UNC).

The workpiece may be supported between a pair of points called centres, or it may be bolted to a faceplate or held in a chuck. A chuck has movable jaws that can grip the workpiece securely.

There are some effects on material properties when using a metal working lathe. There are few chemical or physical effects, but there are many mechanical effects which include, residual stress, microcracks, workhardening and tempering in hardened materials.

 

Exercise 7. Prepare the brief report about modern lathes.

 

Section III. Screw Machines

Grammar: Gerund.

Speaking: Screw Machines.

Screw Machines

Study vocabulary:

a screw machine = screw-cutting machine – винтонарезной станок