Grammar Revision exrcises

1. Read and translate the sentences paying attention to different forms and functions of the Participle:

   1. The numbers being coded on a punched paper tape will control the machine.

   2. The numbers controlling the machine are coded on a punched paper tape.

   3. Being a form of programmable automation numerical control was initially introduced into the machine-tool industry.

   4. The numbers coded in the program specify x-y-z coordinates.

   5. Having been implemented by the computer the form of numerical control was called computer numerical control (CNC).

   6. Having been developed since its initial use to control machine tools numerical control acquired many other applications.

   7. Having changed the form of numerical control programmers and designers transformed CNC into DNC.

II. Read and translate the sentences paying attention to the Absolute Participle Construction:

1. Numerical control is a form of programmable automation, a machine being controlled by numbers coded in some storage medium.

2. The numbers having been coded on a punched paper tape, the position of the cutting tool relative to the work part became controlled.

3. A position feedback control system having been applied, the coded instructions were performed and verified.

4. Today, a small computer is used as the controller in an NC machine tool, the program being actuated from the computer memory.

5. Part programs are sent over telecommunication lines from the central computer to individual machine tools, the use of the punched tape being eliminated.

6. A typical printed circuit board containing dozens of individual components on its surface, the insertion machine requires great precision.

7. The program controls the insertion machine, the information being communicated directly from the computer to the machine.

Oral Practice Tasks

I. Combine parts a and b to form the sentences and translate them:

A 1. The program 2. Many applications of numerical control 3. The lead wires of the components 4. The program that controls the machine

B a. indicates which components are to be placed on the board and their locations. b. must be inserted into small holes in the board. c. is actuated from the computer memory rather than the punched paper card. d. have been developed since its initial use to control machine tools.

II. Complete the sentences with the facts from the text:

1. It should be stressed that numerical control is … .

2. Today a small computer is used as … .

3. The form of direct numerical control involves … .

4. Other machines using numerical control include … .

5. As it is known, the component-insertion machine is used … .

III. Put the points of the plan in the corresponding order:

1. The purpose of a small computer in an NC machine tool.

2. Numerical control as a form of programmable automation.

3. The component-insertion machine and its function.

4. The applications of numerical control.

IV. Answer the questions:

1. What is numerical control?

2. What was the initial application of numerical control?

3. What does the NC part program represent?

4. What can you say about the role of a small computer in numerical control?

5. What do you know about the applications of numerical control?

6. What is the component-insertion machine used for?

V. Find in the text the names of 5 machines. Mention the function of every machine.

VI. Make a short report on numerical control and the role it plays in automation.

Text 9b

Translate the text in written form using a dictionary:

from nc to cnc

Numerically controlled (NC) machine tools are machines that are automatically operated by commands that are received by their processing units. NC machines were first developed soon after World War II and made it possible for large quantities of the desired components to be very precisely and efficiently produced (machined) in a reliable repetitive manner. These early machines were often fed instructions which were punched onto paper tapes or punch cards. In the 1960s NC machines largely gave way to CNC, or computer numerical control, machines. (GE had its NC 550 workhorse for many years until they came out with their first CNC (model 1050) in August 1974.).

Numerical Control (NC) was the precursor of today's Computer Numerical Control (CNC), which controls the automation of machine tools and the inherent tool processes for which they are designed. The CNC machine tool is the servo actuator of the CAD/CAM (Computer Assisted Design/Computer Assisted Manufacturing) technology both literally and figuratively. CNC inherits from NC the essential character of by-the-numbers interpolation of transition points in the work envelope of a multi-axis motion platform, based on the separation of programming from operations. The set of instructions, or "program" (usually an ASCII text file in which, in its simplest form, a line of text specifies the axial coordinates of a point in the work envelope) is prepared from a blueprint or CAD file and transferred to the memory of the CNC via floppy drive, serial data interface or a network connection. Once stored in the CNC memory and selected, the program is executed by pressing the appropriate key on the machine operator panel.

Text 9c

Look through the text and do the tasks below:

Microcomputers and numerical control

Traditional numerical control (NC) is based upon the movement being controlled via a pre-prepared punched paper tape. The development of microprocessors and compact computers has extended the sophistication of the control available, so that the term "computer numerical control”(CNC) is used.

Numerical control machine tools have been used for many years prior to the development of the microelectronics. The application of microcomputers allows for more sophisticated control. When metal is machined, its cutting properties can vary throughout the workpiece¹, particularly if it is a forging² or casting³. Microcomputers can add a further aspect of adaptive control by reacting to the current power consumption⁴, torque, etc. of the driving motors.

Due to the nature of microcomputer systems a distributed processing approach⁵ can be adopted for the control of the various functions of a machine tool. This also allows a modular approach to the development of the hardware and software. In addition, greater operator interaction for unexpected situations is possible due to the work cycle not being restricted to preprogrammed punched paper tape.

Instead of being a substantial part of the cost of a machine tool, the use of microcomputers makes the numerical control cost less and adds relatively little to the cost of the machine tool.

The calculation of optimum tool life⁶ from theoretical laws, for example, is not practical because of the variations in the properties of the actual workpiece. Optimum tool life more realistically should be based upon actual experience. It is feasible⁷ nowadays to monitor and analyse data to recalculate continuously optimum tool life.

Notes:

¹workpiece – заготовка

²forging – поковка

³casting – отливка

⁴consumption – потребление, расход

⁵ approach – концепция; метод; подход

⁶ tool life – стойкость инструмента

⁷ feasible – осуществимый; возможный

1. Translate the title of the text.

2. Formulate the main idea of the text.

3. Choose the main information from every paragraph.

4. Make up the plan of the text.

5. Write down the annotation of the text in Russian.