Ceramic molding process

1. CERAMIC MOLDING PROCESS
VINAYAK KUMAR
212314011

2. INTRODUCTION
 Ceramic molding has been around for centuries.
 Ceramic molding is an offshoot of the investment-
molding process but can cast materials at much
higher temperatures.
 Ceramic casting uses refractory ceramics for mold
material.

3. THE PROCESS
 Silica grains plus ethyl silicate, water, alcohol and a
gelling agent such as HCL are used.
 Slurry is poured around the pattern.
 Allowed to gel in about 4 to 7 minutes.
 Pattern is then removed.
 Mold is fired by igniting the alcohol.
 Firing will burn off any unwanted material and make
the mold hardened and rigid.

4.  Firing of the mold produces a network of
microscopic cracks(microcrazing) in the mold
material.
 These cracks give the ceramic mold both good
permeability and collapsibility for the metal casting
process.

6.  Once prepared, the two halves of the mold are
assembled for the pouring of the metal casting.
 Often, the ceramic mold will be preheated prior to
pouring the molten metal.
 The metal casting is poured, and let solidify.
 Like in other expendable mold processes, the
ceramic mold is destroyed in the removal of the
metal casting.

7. PROPERTIES AND CONSIDERATIONS
 It can produce parts with thin sections.
 Excellent surface finish, and high dimensional
accuracy.
 Eliminates the need for machining.
 Can be used to manufacture ferrous and other high
melting point metal casting materials because can
withstand extremely elevated temperatures.
 Relatively expensive.
 Long preparation time of the mold.

8. FEATURES
 Tolerances: 0.4 %.
 Surface finish: 2 - 4 µm.
 Wall thickness: may be as small as 1.25 mm.
 Weights: Range from 60 gm to 1000kg.
 Draft allowance: 1° recommended.
 Patterns: Reusable and cheap.
 Casting size: generally not restricted.

9. CERAMIC MOLD PROCESS
COMPARED WITH INVESTMENT CASTING
Casting
requirements
Investment casting Ceramic mold
casting
Surface smoothness 80-125 µinch 100-125 µinch
Intricacy Excellent Excellent but not as
investment casting
Thinness of metal
sections
Excellent Excellent
Tolerance Excellent Good to Excellent
Machining cost Minimum machining
required
Machining greatly
reduced
Lead time Longest lead time Very short lead time
Adaptability to various
sizes
Ounce to 300 lb No limitation
Adaptability to various
metals
No limitation No limitation

10. APPLICATIONS
 Impellers, complex cutting tools, plastic mold
tooling etc.

11. Thank you