Baking & Snack - March 2006 - 71

PROCESSING TECHNOLOGY

ᮤ PLC control over wire-cut systems enables rapid changeover and
consistent performance.
APV BAKER

fat will form on the surface of the die opening. This also
facilitates extraction of the moulded dough piece.
When setting up rotary moulders, all three rollers
must be absolutely parallel. The dough feed and die rollers are generally set about ¼ in. (6.35 mm) apart by an
adjustable system. Newer designs permit adjustment of
deposited weight across the length of the roll. Some lines
insert a metal detector ahead of the dough hopper or die
roller, thus protecting the die roller from damage.

can design a 2-stage cutting pattern with successive rollers having alternating halves of the finished shape. The
web of extra dough is returned for scrap.
Lines must be laid out not only to achieve the speeds
desired but also to synchronize the actions of the
embossing, docking and cutting steps.
Because rotary moulding is faster and generates no
scrap dough, it replaced sheet-and-stamp methods for
production of most surface-embossed cookies.
Rotary moulded. This method produces America's
single most popular cookie, the Nabisco Oreo chocolate
sandwich cookie. These cookies are made from a thick
dough that generally contains no particulates and is
mixed to achieve uniform dispersion of ingredients without developing the gluten.
The depositing system consists of feed hopper, die roller,
dough feed roller and extraction roller. The dough feed
roller has deep grooves machined along its length to help
move the thick cookie dough out of the hopper and into
the cavities of the die roller. The two rollers turn in opposite directions pulling the dough down between them.
A scraper blade set against the die roller removes excess
dough. Continuing its rotation, the die roller comes into
contact with the rubber-coated extraction roller that carries a cloth conveyor belt. The belt presses against the die
roller, creating a degree of suction that, when the pressure is relieved as the rollers turn, extracts the formed
dough from the dies onto the conveyor belt.
The die roller's impressions must be
machined precisely, even to the correct pitch of the side of the die openings to ensure clean extraction of the
moulded cookie. According to baker
preference, die rollers can be coated
with a permanent release material to
assist extraction of the dough piece.
Some rotary moulder designs employ
other features to aid extraction. These
include systems that blow hot air onto the
die roller surface or circulate hot water within
the roll. When such features are used, a fine film of
74 / BAKING & SNACK / March 2006

CUT, DEPOSIT OR EXTRUDE? To give cookies more
homemade appeal, bakers developed the wire-cut technology. Depositing handles softer more delicate doughs, and
with extrusion, more product possibilities opened up.
Wire cut. Nabisco Chips Ahoy! chocolate chip cookies
are typical of wire-cut products. They mimic the handdropped method of making cookies at home or in a retail
bakery. The process is widely used in the US and less so
in Europe. Doughs processed by this method can include
a wide range of particulates such as chocolate chips, nuts,
candy pieces, dried fruits and so forth. Ingredients need
to be uniformly dispersed, and to avoid breaking down
the particulates, these materials are added late during
mixing. No gluten development is desired, but the dough
should be cohesive enough to withstand the cutting action of the depositor yet provide a clean cut.
Wire-cut systems receive dough through a supply hopper that allows it to drop between two counter-rotating
fluted feed rollers, spaced ¼ to ½ in. apart. These rollers
force the dough down through a series of openings located on a die plate at the bottom of the hopper. A reciprocating frame, or "harp," carrying a taut wire (approximately 0.03 in. in diameter) is moved across the face of
the die plate, cutting off pieces from the dough streams
as they are forced through the openings.
Nutmeats and chunk chocolate particulates can be
larger than the typical gap between the two feed rollers.
To prevent these from being crushed by the dispensing
action of the wire-cut system, an adjustable gap system
is needed.
Filler blocks can aid the movement of dough through
the hopper and reduce variations in weight between center and end rows. These blocks sit on top of the die, filling
the reservoir under the feed rollers and creating cylindrical channels to guide the dough into the die opening.
Often the wire-cutting action will result in an ovalshaped cookie. To compensate for this malformation, the
openings of the die plate can be engineered with an oval
contour. Die openings in wire-cut machines are sized and
placed to account for the spread of the cookie during baking. Some die plates will have a double, staggered row of
openings, thereby doubling the production rate. Wire-cut

Baking & Snack - March 2006

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