Polymeric Composite Resins in Injection Moulding - Introduction to Polymeric Composites with Rice Hulls - page 138

With the abundance of rice hull biomass available the world over and newer polymers
from non-petrochemical sources being offered in the marketplace as well as ongoing
composite development taking place, one could conclude that these exciting polymeric
rice hull composites are materials with a great future for injection moulders. The
availability of training programmes by some well-known manufacturers of these
composite materials to assist injection molders can only enhance and establish
the advantages of using them in comparison with traditional petrochemical-based
materials.
11.7.1 Causes for Rejection of Parts in Injection Moulding
As in any manufacturing process, injection moulding is also subject to rejection of
parts due to moulding faults. Some of the basic ones are:
• Warp : Insufficient cooling, de-moulding too fast
• Blooming : Colour not mixed properly, excess water present
• Shrinkage : Insufficient material, insufficient cooling, mould fault
• Splay : Excess colour, colour not mixed properly
• Streaking : Excess material shear
• Under-filled: : Insufficient material
In general, injection moulders employ strict quality-control methods, one of which is
using SPC with International Organization for Standardization (ISO) standards such
as ISO 9001, 9002 or the more sophisticated QS 9000 as required by the automotive
industry.