Gökhan Malakçı-030070802-4th week

Nitriding 05 Mart 2011 22:53

Nitriding is a treatment in which nitrogen is diffused into the surfaces of special alloy steels to produce a thin hard casing without quenching.To be most effective, the steel must contain certain alloying ingredients such as aluminum(0,85-1,5%) or chromium(5% or more).These elements form nitride compounds that precipiate as very fine particles in the casing to harden the steel.

(M.Groover. Fundamental of Modern Manufacturing, page 654)

Carburizing 04 Mart 2011 00:09

Carburizing is the most common surface-hardening treatment.It involves heating a part of low carbon steel in the presence of a carbon-rich environment so that C is diffused into the surface.In efect the surface is converted to a high carbon steel, capable of higher hardness than the law-C core.The carbon-rich environment can be created in several ways.One method involves the use of carbonaceous materials such as charcol or coke packed in a closed container with the parts.

(M.Groover. Fundamental of Modern Manufacturing, page 654)

Honing 05 Mart 2011 22:53

Honing is an abrasive process performed by a set of bonded abrasive sticks.A common application is to finish the bores of internal combustion engines.Other applications include bearings , hydraulic cylinders, and gun barrels.Surface finishes of around 0.12 qm or slightly better are typically achived in these applications.In addition, honing prıduces a characteristic cross-hatched surface that tends to retain lubrication during operition of the component,thus contributing to its function and service life.

The honing tool consists of a set of bonded abrasive sticks.Four sticks are used on the tool, but the number depends on hole size.Two to four sticks would be used for small holes, and a dozen or more would be used for larger diameter holes.

(M.Groover. Fundamental of Modern Manufacturing, page 612)

TURNING CENTRES / CNC LATHES 03 Mart 2011 21:00

CNC lathes are widely used in making components with axisymmetric geometry.These are generally machined with 2-axis control. (Z-axis parallel to the spindle and X-axis perpendicular to spindle axis). A CNC lathe is shown in Fig. 12.15. Some CNC lathes have an additional Y-axis. CNC lathes are usually designed with a slant bed for easy removal of chips, at the same time maintaining the rigidity of a closed box structure.A chip conveyor (either magnetic or mechanical) is usually provided for easy chip disposal.The control console is located on the front on top side. The spindle is driven usually by an infinitely variable speed AC drive through a set of V-belts or poly belts. The high power series motors employed provide almost constant power for a large portion of the speed range. High-speed machines usually have integral rotor spindles. AC servomotors drive the X and Z slides usually. Sliding doors (sometimes automatic) with bulletproof glass windows are provided for safety and visibility of the machining zone. Hydraulic chucks are provided for clamping the workpieces. CNC lathes, being high-speed machines require special highly accurate and well-balanced chucks. Tools are mounted in indexable turrets which can hold 8, 12 or 16 tools.

Cad/Cam/Cim P.Radhakrisnan page 361)