Page 157 - Module DMV20173

8.0 POWDER PROCESSING

Figure 8.6 (a) Extruding and (b) jiggering operations.

Example 8.4

What is jiggering? What shape does it produce?

Solution:
Fine size particles Jiggering is a proses of shaping with rotating mould rolls
on the surface of ceramic compacts.

IV) PRESSING

Pressing is a process where ceramic compacts may be subjected to a

pressure in order to achieve uniform compaction and density. Some of the
pressing processes in ceramic manufacturing are dry pressing, hot pressing,
wet pressing and isostatic pressing.

a) Dry Pressing
i. Dry pressing is used for relatively simple shapes, such as whiteware,
refractories for furnaces, and abrasive products.

ii. Density can vary significantly in dry-pressed ceramics (as in P/M
compaction) because of friction among the particles and at the mould walls.

b) Hot pressing
i. In this process (also called pressure sintering), the pressure and the heat

are applied simultaneously.
ii. This method reduces porosity and, thus, makes the part denser and

BPLK 189 DMV 20173