Dimensional Accuracy in RP of Ceramics Using Injection Molding

Parties Involved:

• Student(s): Beth Judson
  Faculty Member(s):  Tom Star
  Industry Member(s):  Lucent,  3D Systems,  Kodak
   

Brief Project Description:
 

• In this project,  efforts are being driven towards the ability to predict the shrinkage of a new geometry in order to meet manufacturing tolerances.
• Current modeling software assumes isotropic shrinkage, however in the real world, anisotropy is a result of process dynamics due to the viscoelastic behavior of the molten feedstock under an applied stress causing particles and molecules to orient in a direction influenced by shear flow.
• Beth Judson, under guidance of her academic advisor, Tom Star, is currently implementing a four step procedure that is expected to improve the dimensional accuracy in rapid prototypiong of ceramics using injection molding.
• Significant findings to date include:
  1. A relationship exists between the volume shrinkage of parts and the ratio of volume to surface area for the shape.
  2. The shrinkage was less variable with crosswise gating.
  3. Anisotropy is more pronounced in thin walled parts than in thicker parts.