MAINTENANCE
Although clay feels slippery to the touch, it is quite abrasive on machine parts. The flywheel
press must be lubricated daily in all places where steel parts move: on the threaded shaft, the
die slides, the shaft die bearing, and the lower die rails. Periodically the press should be
stripped of oil, cleaned, and relubricated to remove residual grit from the slides and bearings.
The dies themselves are lubricated with each slab of clay (see Operation of a tile production
unit). Typically the joining of dip plates themselves determines the stopping place for the
flywheel. In pressing, sufficient clay is put into the press so a layer of clay is squeezed out
between the dies to avoid steel on steel contact of the die plates. Even so, the die plates do
wear down, and must be replaced after producing approximately one million tiles, depending
on the specific clay and tile design. In active Sri Lanka factories, this means every six
months.
2.3 TRIMMING STANDS
The pressed tiles must be trimmed of flashing remaining from the moulding process (see
figure 3). To allow easy access to all sides of the tile a rotating stand head is used, so the
trimmer can stand in one place and turn the tile with ease. This type of head can be built in
many ways. Below is shown a common box head arrangement which is quite sturdy and easy
to construct.
Figure 3: Trimming a tile on a rotating head stand. The stick on the stand is used for slapping
the sides of the tile.