Name  _______________________

 

Casting Assignment

 

Note:  Time = B(V/A)2  (Chvorinov's equation)

 
  1. Set the mold and material constant (B) = 1
  2. The volume (V) of a cylinder:
  3. The area (A) of a cylinder:

 

The minimum solidification time for a riser should be approximately 25% greater than the total solidification time of the casting: triser = 1.25tcasting.  Using Chvorinov’s rule method (n = 2) as described in the lecture, with a 2.0” high (H) cylindrical riser shape, determine the minimum radius required in the riser to be used in the casting flask with the part shown above.  Assume the bottom of the cast part is flat, and disregard the volume changes due to the fillet blending at the bottom of the cylinder with the top surface, and any draft requirements of the casting.  The radii on all four corners of the part are ˝”.  Show calculations with boxed solution on a separate sheet stapled to this handout.

 
  1. The volume of the part shown above = _______________
  2. The surface area of the part shown above = ______________
  3. The radius of the 2.0" high riser used for the part = ____________
  4. From your calculations, is the volume of the part greater or less than the volume of the riser.  If greater, how is it possible that the riser takes longer to solidify?

 

Solution