MACHINING 1 PROFESSIONAL ENGLISH IN USE FOR ENGINEERING

 

PROFESSIONAL ENGLISH IN USE FOR ENGINEERING UNIT 23. MACHINING 1

 

A Machining and CNC Machining is the use of machines to cut pieces of material (called workpieces) and shape them into components. The tools used in machining, to make holes, grooves, threads, etc., are called machine tools. Metal is often machined. As it is cut, waste ids produced, called swarf or chips. During machining, a liquid called cutting fluid may be pumped onto the workpiece to act as a coolant, keeping the workpiece cool. B Machining with cutting tools Below are the most common machining techniques which use cutting tools. Milling is cutting done by a milling machine, often using toothed cutting discs (wheels with teeth that have sharp edges). When a workpiece is milled, it is held in a fixed position on the machine, and is shaped by cutting tools which rotate (spin) while being moved over the surface of the workpiece. Drilling is a technique for cutting circular holes. A machine called a drill is fitted with a tool called a drill bit (or bit). The bit rotates and drills into the material. Holes with large diameters can be cut using holesaws – hollow cylinders with teeth, which saw circular cuts and remove a core (a solid cylinder) of material. When used to drill into concrete, this technique is also called core drilling, or diamond drilling, as the holesaws have industrial diamond edges. Usually, drilling refers to making new holes. In machining, enlarging a hole (making it wider) is called boring. Grinding is removing material across a surface area, using abrasive wheels. The machines used to grind materials with abrasive wheels are called grinders.   EXERCISES 23.1 Match the two parts to make correct sentences. Look at A and B opposite to help you. 1. A drill bit is an example of 2. Material being machined is called 3. The waste metal produced during machining is called 4. Metal gets hot during cutting, so cutting fluid can be used as 23.2 Complete the descriptions below the photos using the words in the box. Look at B opposite to help you. abrasive blade cores drill grinder holesaw toothed bit circular diamond drilling hacksaw saw wheel 23.3 Complete the sentences using the words in the box. Look at B opposite to help you. drill grind mill turn saw 1. Lathes are designed to ____________ workpieces. 2. Different bits are designed to ____________ into different types of material. 3. When you ____________ a workpiece, the cutting blade removes a thickness of material to forma kerf.

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