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Northern
Foods' divisional company, Park Cake Bakeries operates a bakery, which is
largely dedicated to supplying a wide range of cakes and other products to a
single UK food retailer. Many of the cakes are decorated and often this entails
written messages iced on the top - a task generally undertaken by skilled
staff, trained to maintain a consistent high standard of
work.
However, at certain times of the year -
Easter and Christmas, for example - there is a significant increase in demand
which can result in as much as four times the normal throughput. Training
additional staff to cope with the expanded demand while still maintaining the
normal high levels of quality can take a significant period of time and so
volume planning is critical.
For some time now, the Park Cakes
management team has been looking for new ways to manage this problem. Group
engineering controller, Terry Simpson wondered whether modern technology could
be applied to help with the task and realised that robots might possibly be
adaptable for the cake decoration process. The search for a partner in this
project, however, turned out to be something of a crusade !
Many companies were approached, but none
were able to supply a solution, which met the criteria - none, that is, until
he met up with a company called System
Devices. "When I
first met their engineers it was clear that they had the right attitude and
they were people I could do business with," Mr Simpson recalls. "I already had
a clear idea of what I wanted to achieve but previously it had been difficult
to make other organisations fully understand." The company was duly appointed
to develop a prototype cake icing machine.
 System Devices are UK agents for Epson
robots and the Opto 22 Mistic control system. Initially, the message to be iced
on a cake was 'drawn' on a CAD package and its co-ordinates downloaded to the Mistic controller which converted the information into smoothed co-ordinate
data for an Epson Scara robot guiding a suitable icing nozzle - this is where
IDS got involved.
Both System Devices and Park Cake approached
Simon Meredith at
Integrated Dispensing Systems to source a suitable
dispense valve and nozzle to apply the chocolate icing on the cakes and would
do so with a clean cut-off without any stringing. IDS had a ready made solution
in their stainless steel
2200-245-Series KISS™
Tip Seal Valve. With its cavity free tip seal nozzle it gave a clean
cut-off of the icing bead every time the valve was closed. The valve was
mounted on a heater block and the valve supplied with warm icing through a
heated hose. The valve is built with two inlet ports enabling the valve to be
configured so that the icing could be recirculated through the valve - a very
important feature when working difficult materials such as
chocolate.
 There were teething problems with the early
prototype, not in respect of positioning the nozzle, but with controlling rate
of flow of the chocolate and icing materials from the nozzle. This was solved
by System Devices working on experience gained in other industries, and with
the help from IDS and a chocolate technologist who provided input on the
appropriate consistency and flow characteristics for this application. Further
development ensured that the prototype was able to cope with the varying
overall heights and surface levels of the cakes themselves. With these
encouraging results, System Devices was invited to build a production version
of the prototype, capable of icing two cakes simultaneously.
 In the final version, messages are formed
using a CAD package on a PC in a remote control room. This is downloaded via a
RS232 to the robot-mounted Mistic controller, which converts the data to
machine co-ordinates, as well as controlling the icing nozzles. Cake surface
variations are measured in real time by a laser range finding system and these
parameters are fed back to the Mistic, which compensates for each individual
profile.
Cakes are fed to the robot via a conveyor;
as this is loaded by hand and the position of the cakes is critical, a simple optical positioning aid, involving two lasers, was developed by System Devices
to ensure consistently accurate presentation. Mr Simpson is enthusiastic about
the project. "The quality of decoration has exceeded our expectations and our
customer is extremely pleased with the results."
Recent developments have included an
expansion that will enable four cakes to be iced at a time, and the provision
of other types of decoration.
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