II. Memorize the meaning of the following words and word-combinations from Text 8.

1. automatic assembling machine -автоматизированное сборочное устройство

2. numerical control machine -устройство с числовым программным управлением (станок)

3. output velocity -скорость на выходе

4. lathe -токарный станок

5. milling machine -фрезерный станок

6. cutting-tool speed -скорость резца

7. cutting depth -глубина резания

8. feed rate -скорость подачи

9. computer-aided design -автоматизированное проектирование

10. computer-aided manufacturing -автоматизированное производство

11. computer-integrated manufacturing -комплексно-автоматизированное производство

Ш. Look through Text 8 to find out the following:

1. Where is numerical control used?

2. What is the function of the controller?

3. How long have numerical control machines been used?

4. What program is used to read the CAD-generated drawing?

5. How is this whole process called?

6. What is the advantage of this process?

7. What does computer-integrated manufacturing involve?

Numerical control (NC) is the type of digital control used on machine tools such as lathes and milling machines. These machines can automatically cut and shape the workpiece without a human operator. Each machine has its own set of axes or parameters that must be controlled; as an example, consider the milling machine shown in Figure 1.12. The workpiece that is being formed is fastened to a movable table. The table can be moved (with electric motors) in three directions: X, Y, and Z. The cutting-tool speed is automatically controlled as well. To make a part, the table moves the workpiece past the cutting tool at a specified velocity and cutting depth. In this example, four parameters (X, Y, Z, and rpm) are continuously and independently controlled by the controller. The controller takes as its input a series of numbers that completely describe how the part is to be made. These numbers include the physical dimensions and such details as cutting speeds and feed rates. NC machines have been used since the 1960s, and certain standards that are unique to this application have evolved. Traditionally, data from the part drawing were

entered manually into a computer program. This program converted the input data into a series of numbers and instructions that the NC controller could understand, and either stored them on a floppy disk or tape, or sent the data directly to the machine tool. These data were read by the machine-tool controller as the part was being made. With the advent of computer-aided design (CAD), the job of manually programming the manufacturing instructions has been eliminated. Now it is possible for a special computer program (called a postprocessor] to read the CAD-generated drawing and then produce the necessary instructions for the NC machine to make the part. This whole process—from CAD to finished part—is called computer-aided manufacturing (CAM). One big advantage of this process is that one machine tool can efficiently make many different parts, one after the other. This system tends to reduce the need for a large parts inventory. If the input tape (or software) is available, any needed part can be made in a short period of time. This is one example of computer-integrated manufacturing (CIM), a whole new way of doing things in the manufacturing industry. CIM involves using the computer in every step of the manufacturing operation—from the customer order, to ordering the raw materials, to machining the part, to routing it to its final destination.