Oğuzhan Paçal, 030070031, 5th week

Chvorinov's Rule:

The size of feeders and risers are shaped according to the volume and shape of the area. In a proper molding process feeders and risers are supposed to be the last solidifying parts. The time required for solidifying is calculated using the "Chvorinov's Rule" .

ts=Cd*(V/A)^n

ts is solidification time , Cd is die coefficient, V is volume and A is total area of the part.
(Manufacturing Methods, Casting Technology Lecture Notes, A.Aran, p. 29)

Riser :

In casting there is usually a problem about the solidification. When material is molded thin areas and corners solidify faster than inside of the part which causes unwanted strain inside the part and this makes it fragile. To prevent the inner strain, riser is used. Risers are designed using the Chvorinov's Rule. When the mold is poured, risers solidify the latest so that the unwanted inner strain is avoided.
(Manufacturing Methods, Casting Technology Lecture Notes, A.Aran, p. 28)

Mold Erosion :

In die casting the process should be continous and uniform, and the process speed should allow the solidification to start right after the molding is finished. Casting speed is the materials' speed of pouring into the die, and if the casting speed is too much, the flow becomes turbulent. Turbulence has two important dangers:

• Material is exposed to air much more than laminar flow
• Mold Erosion is occured

This flow makes the die lose the form. To prevent mold erosion the travelling canals should prepared more narrow at deeper and as it is mentioned before the pouring process should be done in certain speed limits.
(Manufacturing Methods, Casting Technology Lecture Notes, A.Aran, p. 14)

Computer Aided Part Programming :

Computer aided part programming involves special symbolic programming languages that determine the coordinate points of corners, edges, and surfaces of the part. A programming language is a means of communicating with the computer; it involves the use of symbolic characters. The programmer describes in this language to componnent to be processed, and the computer converts that description to commands for the NC machine. Serveral languages are available commercially.
(Kalpakjian S. & Schmid S., Manufacturing Engineering and Technology, p.1160)