Sezgin Koçak 5th week

Centrifugal casting:

Centrifugal casting, due to inherent nature of the procedure itself, is only suitable for producing rotationally symmetric castings. In the centrifugal casting procedure, a chill mold is put into horizontal or vertical rotation and is filled with liquid material. The wall thickness or inside diameter of the solidifying tube-shaped casting is determined by the amount metal added. The solidification of melted metal takes place very rapidly and can be increased by additional cooling. A dense fine-grain microstructure is achieved by the influence of centrifugal force and extremely fast solidifying. This casting procedure is excellently suited to produce plain bearings and together with continuous casting is of great importance for producing stock material for plain bearings.

(H. Lipowsky,E.Arpaci, Copper in the automotive industry, p.49)


Calendering:

In its simplest form, calendering equipment consist of two heated parallel rolls and the equipment is often called a two-roll mill or a batch mill. Polimer powder and plasticating and foaming ingredients are introduced into the nip redgions of these rolls. The polimer melts against the rolls and typically adheres to one of the two rolls, sometimes called the lead roll. The adhetives are dosed into the nip region and squeezed into the polymer. The plasticating temperature must be below the chemical foaming agent decomposition temperature to minimize premature foaming.

(J. L. Throne, Thermoplastic foam extrusion: an introduction, p.73)

Boolean Operations:

A Boolean operation usually affects two objects at any one time, and is the basis of the binary systems that underline most of computing. Boolean opertations are absolutely fundamental in CAD, and allow the creation of complex forms and compositions by their succesive application to objects that may initially be quite simple. Several of the later case studies illustrate just how important they are in generating form. Learning how to think in terms of applying successive Boolean operations to generate a particular form is essential for CAD users. Examples of some Boolean operations; add, subtract,intersect.

(P. Szalapaj, CAD principles for architectural design: analytical approaches to computational representation of architectural forms, p. 75)

Friction Welding:

In principle, friction welding is a press welding method. Intensive friction leads to local heating between two components so that the parts finally weld together without reaching the liquid phase. Therefore, friction welding can be done in air. By intensive rubbing and additional pressure, the surfaces are heated up to temperatures where the usually hot forming takes place,i.e., kinetic energy is converted into heat to bring about controlled degrees of fusion. Although cylindrical workpieces are like shafts or flanges are particularly suitable for this method, friction welding has recently attained a special attention for the production of "blisks"(bladed disks) in jet engine compressors. Friction welding offers cost advantages, particularly for larger blisks sizes.

(C.Leyens, M. Peters, Titanium and titanium alloys: fundamentals and applications, First Edition, p.252)