Exercise 3.4 Read for Specific Information

Read and translate the statements. Fill in the missing words and word-combinations.

1 Feedback controls are widely used in …………… to ensure that the programmed com­mands have been properly executed.

2 A feedback control system consists of ………….. compo­nents.

3 The input signal ……… the desired value of the process output.

4 The output is some variable that is being measured and compared with the ……. .

5 The process input is determined by …………. in an automated system.

Exercise 3.5 Increase Your Vocabulary.

You may have come across the following words before but perhaps not used in quite this way. Suggest words or phrases which might replace them:

Feedback basic compo­nent sensing element

loop input output

adjustment to reduce to direct

rotation to convert to sense

Exercise 3.6 Make up the sentences of your own using the words of Exercise 3.5

Exercise 3.7 Choose the Correct Definitions for Terms

Match each term with its definition. Translate these definitions into Ukrainian.

TO CONVERT	Changing something slightly especially if it is not in the right position
ADJUSTMENT	Information or comments about something that you have done which tells you how good or bad it is
FEEDBACK	To change from one form, system or use to another
ELEMENT	To find the size, weight, quantity in standard units by using instruments
TO MEASURE	One important part of something

Exercise 3.8 Learn to Write a Summary

Give a short summary of the text in writing.

Exercise 3.9 Controlled Practice

1. Find sentences with Infinitive. Translate them into Ukrainian.

2. Find sentences with Present Continuous Passive Voice. Translate them into Ukrainian.

Exercise 3.10 Focus on Translation

Translate the following sentences from Ukrainian into English.

1“Управління зі зворотним зв’язком” широко використовується в автоматизованих системах для перевірки, чи програмові команди були правильно виконані.

2 Це управління складається з 5 основних елементів.

3 Контрольна програма складається з послідовності кроків (команд), кожна команда, в свою чергу, посилається до контролера системи.

Exercise 3.11 Discussion Point

Talk it over.

What are the components of a feedback system? How does the feedback system operate and where is it used?

Unit 4

Machine Tools

Pre-reading Task

Scan the text for the main idea, answer the following questions:

1. What do NC, CNC and EDM mean?

2. When did the first steam-engines appear?

Text

Machine tools are the machinery used to process metals and nonmetallic materials to get desired shapes or properties in manufacturing industries. Therefore, they constitute the core of manufacturing systems. The modern form of machine tools was first introduced during the industrial revolution in the 18th century with the birth of steam engines. Those steam engine-powered machine tools opened the era of automation along with the use of jigs and fixtures. Particularly, the continual development of new tool materials since the early 20th century has been the major driving force in advancing the technology of machine tools. More rigid and higher speed machine tools have been required to use fully the capability of new tool materials. It is not uncommon to see machining operations of cast iron with cutting speeds exceeding 3000 fpm in the automotive industry today.

The way of automation using machine tools changed significantly as the demands of market shifted from inflexible automation for mass production to flexible automation for batch produc­tion. The introduction of numerically controlled (NC) machine tools made it possible to perform a variety of jobs on a single machine. Since its inception, the use of NC machine tools has shown a rapid growth. Currently, more than 75% of the money spent to purchase new machine tools goes to computer numerically controlled (CNC) machine tools.

Accuracy of CNC machine tools has improved significantly. Accuracy better than 0.0002 to 0.0003 in. is commonly achieved on production CNC machining centers at present. This im­proved accuracy is attributed to construction of more rigid and precision mechanical compo­nents, use of computer controlled compensation of positional errors, and adoption of more advanced microprocessors to generate required trajectory commands. In modern CNC machin­ing centers, many in-process sensors are used to feedback various operating conditions to the controllers. In some cases, machine controllers can make adjustments automatically to improve accuracy or performance.

Similar progress has been made in forming machine tools. For instance, precise control of a forming process is achieved by continuous monitoring of pressure or temperature and controlling the ram velocity to improve the properties of a part being formed. Various machine tools for nontraditional processes have also been developed. Electrodischarge machines (EDM) are used to erode the work material by discharging electric sparks between the tool and workpiece. Both spark voltage and feed must be controlled. Laser cutting machines can cut various difficult-to-cut materials by focusing high energy light beams onto a small area and thereby vaporizing the material.

In general, most machine tools require precise motion control with feedback of various sensor signals. Manufacturing processes are typically stochastic, time varying, or uncertain due to the variation of material property, temperature, and environmental conditions. There­fore, true automation of machine tools would require intelligent process condition monitoring, diagnostics, and intelligent control.

Post-Text Exercises

Exercise 4.1 Read and Translate the Text into Ukrainian

Exercise 4.2 Comprehension Check

Answer the following questions:

1. What is the sphere of application of machine tools?

2. What has increased the accuracy of CNC machine tools?

3. How do EDM work?

4. Which is the principle of action of laser cutting machines?

5. How should the true automation of machine tools be provided?

Exercise 4.3 Read for Specific Information

Read through the extract, fill each gap with one of these words.

Translate the sentences into Ukrainian.

Sensors, since, progress, numerous, generation, as, microelectronics, weight.

Microelectromechanical systems technologies have their roots in research activities in the early 1960s, _______ the first micropressure _______ were fabricated using an anisotropic etching method. _______ then, the fabrication techniques developed in _______ _______ have begun directly to impact the _______ in micromechanics.

In the 1970s _______ industrial companies were involved in the efforts to commercialize the existing microfabrication technologies for a new _______ of products featuring lights, _______, small volume and high efficiency.

Exercise 4.4 Increase Your Vocabulary

Give Ukrainian equivalent of the following:

1. to constitute core of manufacturing systems.

2. steam engine – powered machine tools.

3. jigs and fixtures.

4. to shift from inflexible automation of mass production to flexible automation for batch production.

5. to improve the accuracy of performance.

6. to discharge electric sparks between the tools and the workpiece.

7. computer numerically controlled machine tools.

Exercise 4.5 Develop Your Idea about the Text

Make up a plan of the text.

Exercise 4.6 Controlled Practice

1. Copy out from the text sentences in Present Perfect Tense. Translate them into Ukrainian.

2 Put the following sentences into Perfect Tenses.

a) Undoubtedly by the next decade of this century new modern technologies in automation (to develop).

b) The lecturer said that during the past two decades, unprecedented change (to occur) in the competitive environment of the discrete part of manufacturing industry.

c) Process control (to be) most often associated with the processing industries, such as chemical processing, petroleum refineries, etc.

Exercise 4.7 Focus on Translation

Translate the following sentences into English.

1. Парові двигуни були попередниками сучасних машин.

2. Станки, які є невід’ємною частиною будь-якого виробничого процесу, вдосконалювалися протягом декількох століть.

3. Відомо, що комп’ютери дозволяють досягти високого рівня автоматизації в роботі сучасних машин.

4. Постачання ріжучих станків з використанням лазера буде закінчена до кінця цього року.

Exercise 4.8 Discussion Point

Talk it over.

1. Describe the process of development of machine tools.

2. What is the principle of work of machine tools?

Unit 5

Machine Programming

Pre-reading Task

Scan the text for answering the following questions:

1 Machine programs operate the system without human intervention, do not they?

2 What two basic categories can automation production be classified into?

Text

The actions performed by an automated system are determined by a program of instructions. The program operates the system without human intervention, although the automated process or procedure may involve human interaction (e.g., an automated teller machine). The instruc­tions contained in the program specify the details of each action that must be accomplished, the sequence in which the actions must be performed, and variations in the sequence that may be required depending on circumstances.

In the simplest automated systems, the machine actions comprise a well-defined work cycle that is repeated continuously with little or no deviation from cycle to cycle. Many mass produc­tion operations fall into this category; examples include automatic screw machine cycles, stamping press operations, plastic molding, and die casting. These processes date back many decades, and the equipment has traditionally been controlled by hardware components such as cams, electromechanical relays, and limit switches. In addition to controlling the equipment, these components and their arrangement served as the program of instructions that regulated the sequence of actions in the work cycle.

Although these devices are often quite adequate for the modest control action requirements of these programs, modern controllers are based on microcomputers. The program of instruc­tions for computer-controlled production equipment has included a variety of media over the years, such as mag­netic tape, diskettes, computer memory, and other modern storage technologies.

Computer control provides the opportunity for additional functions to be incorporated in the operation, beyond simply regulating the machine cycle. Some of the additional functions in­clude improving and upgrading the control software, including the addition of control functions not foreseen during initial equipment design; safety monitoring; monitoring of process data such as equipment performance and product quality; diagnostic routines for maintenance and to expedite repairs when equipment breakdowns occur; and a convenient human-machine interface. Modern computer-controlled programmable machines also are capa­ble of higher level functions, such as decision making and process optimization.

The decision-making capability of the system is included in the program in the form of instructions that execute different actions depending on conditions and circumstances. Less than one set of conditions, the system responds one way, but under a different set of conditions, it responds in another way.

Decision making also allows an automated system to cope with unanticipated events in the work cycle, such as a broken tool or a part not positioned correctly in a fixture or other malfunction in the process. Many decision-making situations rely on the ability of the system to use sensors to monitor the process and sense the environment. The sensors indicate the pres­ence of the unexpected event, and the program commands the system to deal with the event in an appropriate manner. This type of decision-making capability is often called error detection and recovery.

Process optimization is another aspect of programming in the operation and control of a production process. Optimization is applicable in situations where there is (1) a well-defined economic performance criterion, such as product cost, production rate, or process yield, and (2) the relationships between the process variables and the performance criterion are known. In these cases, the control program is designed to make adjustments in the process variables that tend to drive the process toward an optimal state.