Injection moulding is an attractive method for fabricating ceramic articles. The advantages include high precision forming in dimensional control and the freedom in achieving complex shapes. A prerequisite in obtaining moulded ceramics with an accurate dimensional tolerance is that the moulded products should be free from any shrinkage defect. It has been pointed out that non-uniform shrinkage in injected moulded ceramics often results in defects such as voids, sink marks, curve deformations, weld lines and even cracks [1,2]. The shrinkage defects are reported to be closely related to moulding parameters and sample size, as well as to the blend compositions of compounded mixtures [3]. However, the details about the relative significance of each potential factor and the interactions between factors remain unclear. This letter is therefore aimed at providing such information by designing a statistical L|f,215 experiment to investigate the dominant factors for the formation of sink marks on injection moulded ceramics. Other shrinkage-related defects will be discussed elsewhere.
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