MACHINERY FOR FITTINGS ETC.
Machines used for converting board into fittings Although
the majority of all board produced by the Corrugator is used in the production
of slotted containers or die-cut boxes, there is another requirement for
the safe transit of goods in most packs and that is for internal fittings.
There are two main groups of fittings, those produced by rotary machinery
and those which are die-cut.
Thin is used for producing the many variations of standard
fittings which fall into the four main groups, Surrounds, Scored Fittings,
Divisions (or Partitions) and Pads, which either because the run is too
small or the Triplex unit cannot cope have to be produced as corrugated
sheets and converted elsewhere.
Rotary Cutting and Creasing Machines
The board is delivered from the Corrugator in the form
of blank sheets of suitable size for easy handling, but which will also
allow a practical number to be cut from it of the finished size. The Cutting
and Creasing machine is basically the same as the Triplex unit on the
Corrugator but with the shafts in line, one behind the other. By using
the scoring and slitting tools on all the shafts in the right combination
scores can be set quite close together and are not then dependant on the
width of the bosses to govern the proximity of bends. The boards may then
be passed to the slitting or trimming machines.
Where the size of the finished board is large enough
or Where the position of scores makes it practical when considering the
length of run the scoring can be put in by the Triplex unit before being
passed to the slitting machines.
Rotary Cutting and Half Knife Cutting Machines
Used in the same way as the rotary, cutting and creasing
machines but with a different tool for bending which slits the liner and
fluting on one side of the board leaving the second liner intact. The
result is a bend which can be folded back on itself through 180 degrees
without springing open or splitting. By alternating the side of the board
from which the slits are made, a concertina effect can be produced to
give a thick pad or block when folded (FEFCO style 0966). it is possible
to make two passes through the machine for extra bends and still be able
to form the block without effort.
There are two methods of producing the half-knife cut
and reverse half knife cut. One uses a serrated knife over a flat bobs,
the other uses reduced diameter knife over a female boss. It is possible
to use a combination of normal bends and half-knife cut bonds for one
pass through the machine if required.
Although the Rotary cutting and scoring machines can
be used to cut the board down to second way size, it is more convenient
to use a rotary slitter which has eight pairs of knives only. It is a
smaller machine to set with only one pair of shafts to carry the tools.
Although the larger slitting and scoring machines are
generally hand fed, many of the smaller machines use kicker fed hoppers
and some machines use a suction feed in which the bottom blank is sucked
onto a moving belt by air. These machines are particularly useful for
handling boards which have become slightly warped. Machine speeds. vary
greatly according to size and type of feed and may be between 1800 and
4500 blanks per hour, generally with a crew of two or three.
THE ROTARY SLOTTER
Many containers require divisions, or nests to separate
the items packed within the container and these may be produced using
a rotary slotter. This machine is built in the same way as a Printer Slotter,
but on a smaller scale and without the printing unit. In addition, whereas
the printer slotter has It. or less slotting heads the Rotary Slotter
may have between 9 and 15 slotting beads.
A kicker feed is generally used and the board may be
slit to size 1st way either by the Corrugator or the slitter creaser before
being loaded into the hopper. From there it is fed through slotting heads
set to slot a predetermined distance into the board,
generally a fraction over half way for normal divisions.
Several pieces may be slotted out of one blank fed into the machine, which
will also cut down the slotted blank into its separate division pieces
using knives set on the same or separate shafts.
In order to reduced the number of pieces handled on
the take-off section one or more of the slitting knives may be replaced
by a semi-slit knife. These: knives will cut normally except for one or
two nicks which are sufficient to hold the pieces together for Tore convenient
collection and stacking. Some slotters can also score and slit boards
in the same way as the cutting and creasing machine.
It is customary to assemble sets of divisions at the
manufacturers and then to collapse them flat for ease of transport to
the customer. They may either be assembled by hand which, is essential
for very large pieces, or by one of the various types of assembly machines.
The principal is the same for all machines insofar as they operate by
holding one size (A) of the division set in the requisite position until
the second size (B) is lined up with slot to slot and then pressed home.
The set is then ejected for bundling.
Machine assembly is usually much faster because according
to size and numbers of pieces required, up to 12 sets can be assembled
in one machine cycle.
Most large plants have at least one Corrugator together
with all the standard equipment required for converting the board into
cases and fittings. Some plants however have additional specialized machinery
for performing functions which are not required on a wide scale.
This is an example of special machinery. It is
a process by which a board is passed through a falling curtain of a coating
material which is therefore draped over the surface of the board, the
excess liquid falling into a trough for re-circulation. The material usually
used to form the film is a modified wax blend which solidifies extremely
rapidly on contact with the board, giving a coating of about 35 grams
per square meters.
The coating is required when absorption of water, grease
or oil from either inside or outside the pack must be prevented. It should
be flexible to allow for the normal conversion of the board afterwards.