PRESSES

A press, or a machine press is a tool used to work metal (typically steel) by changing its shape and internal structure.

A forge press reforms the work piece into a three dimensional object—not only changing its visible shape but also the internal structure of the material. A stronger part results from this process than if the object was machined.

Bending is a typical operation performed and occurs by a machine pressing, or applying direct pressure, to the material and forcing it to change shape. A press brake is a typical machine for this operation/

An easy to understand type of machine press is a set of rollers. Metal is fed into the rollers, which are turning to pull the material through. The space between the rollers is smaller than the unfinished metal, and thus the metal is made thinner and/or wider.

Another kind of press is a set of plates with a relief, or depth-based design, in them. The metal is placed between the plates, and the plates are pressed up against each other, deforming the metal in the desired fashion. This may be coining or embossing or forming. A punch press is used for forming holes. Capping Presses form caps from rolls of aluminium foil at up to 660 per minute.

Progressive stamping is a manufacturing method that can encompass punching, coining, bending and several ways of modifying the metal, combined with an automatic feeding system. The feeding system pushes a coil of metal through all of the stations of a progressive stamping die. Each station performs one or more operations until a finished part is made per the requirements on the print. The final operation is a cut-off operation, which separates the finished part from the carrying web. The carrying web, along with metal that is punched away in previous operations, is considered scrap metal.

A brake press is a special type of machine press that bends sheet metal into shape.

A drill press (also known as pedestal drill, pillar drill, or bench drill) is a fixed style of drill that may be mounted on a stand or bolted to the floor or workbench. A drill press consists of a base, column (or pillar), table, spindle (or quill), and drill head, usually driven by an induction motor. The head has a set of handles (usually 3) radiating from a central hub that, when turned, move the spindle and chuck vertically, parallel to the axis of the column. The table can be adjusted vertically and is generally moved by a rack and pinion. The size of a drill press is typically measured in terms of swing. Swing is defined as twice the throat distance, which is the distance from the center of the spindle to the closest edge of the pillar. A drill press has a number of advantages over a hand-held drill:

· less effort is required to apply the drill to the workpiece. The movement of the chuck and spindle is by a lever working on a rack and pinion, which gives the operator considerable mechanical advantage.

· the table allows a vise or clamp to position and lock the work in place making the operation much more secure.

· the angle of the spindle is fixed in relation to the table, allowing holes to be drilled accurately and repetitively.

· Speed change is achieved by manually moving a belt across a stepped pulley arrangement. Some drill presses add a third stepped pulley to increase the speed range. Modern drill presses can, however, use a variable-speed motor in conjunction with the stepped-pulley system; a few older drill presses, on the other hand, have a sort of traction-based continuously variable transmission for wide ranges of chuck speeds instead, which can be changed while the machine is running.

· Drill presses are often used for miscellaneous workshop tasks such as sanding, honing or polishing, by mounting sanding drums, honing wheels and various other rotating accessories in the chuck. This can be dangerous on many presses, where the chuck arbor is held in the spindle purely by the friction of a Morse taper instead of being held securely by a drawbar.

Exercise 6. Answer the questions to the text, using the active vocabulary of the lesson.

1) What is a press?

2) What types of machine press do you know?

3) What is bending?

4) What kind of press is used for forming holes?

5) What is progressive stamping? What does this method encompass?

6) What is a drill press?

7) What does a drill press consist of?

8) What are the advantages of a drill press over a hand-held drill?

9) How can be speed change achieved?

10) What are drill presses often used for?

 

Exercise 7. Translate orally, and make it fast:

 

Изменять форму и внутреннюю структуру, ковочный пресс, bending, подавать металл к роликам, необработанный металл, a set of plates, embossing, чеканить, a punch press, a capping press, алюминиевая фольга, feeding system, штемпелевка, a cut-off operation, металлический лом, sheet metal, фрикционный пресс, a drill press, амплитуда, шпиндель, a chuck, барабан для очистки песком, honing wheel, трение, a drawbar.

 

Exercise 8. Which word doesn’t match the whole line?

1) plasma arc, drill press, electron beam, laser.

2) to vaporize, to machine, to process, to work.

3) metal, plate, aluminum, steel.

4) spindle, clamp, chuck, relief.

5) sanding, honing, milling, polishing.

 

Exercise 9. A typical manual drill press is shown in the figure below. Study the parts of it.

Exercise 10. And now try to find out which parts of the drill press perform the following operations?

1) Moves the drill head up and down.

2) Locks the movement of the drill head.

3) Maintain a specific length of travel.

4) Let the operator know where he is vertically.

5) Can move vertically and rotate about the vertical guide post.

6) Powers the drill.

7) Can be adjusted vertically and is generally moved by a rack and pinion.

Exercise 11. Replace the noun clause by gerund with preposition “of”. Translate the sentences into Russian:

Model:He thought he would change the shape of the metal by press machining. - He thought of changing the shape of the metal by press machining.

1) I’m thinking that I shall use a set of rollers to make this metal sheet thinner.

2) I hear there are some new drill pressers at your workshop. So do you think you will be able to make the whole retooling?

3) I think I shall polish and hone this workpiece tomorrow.

4) What do you think you will do today at work? – I thought I would check the operation abilities of the brake press.

5) We think we’ll deliver a pillar drill today at 6 o’clock. Is that convenient for you?

6) The manufacturers think they will widen the field of application of presses in the nearest future.

Exercise 12. Read the text “Presses” one more time and make the summary of it.