Ishida Case Study Series: Gastro Star AG
Gastro Star AG: speed and control in the sealing
of salad trays
When it comes to increasing line speed, achieving a higher
output is seldom the real issue. Improving, or even simply
maintaining, quality is likely to be more of a challenge.
This was certainly a key concern for Swiss supplier of
prepared salads, fruit and vegetables Gastro Star AG. Plans
to almost triple output on a mixed salad tray filling and sealing
line hinged on the new system’s ability to keep product out
of the sealing area. The installation of an Ishida QX-775
traysealer succeeded in meeting all these objectives.
The company, based in Dällikon in northern Switzerland,
had already been favourably impressed by its experience
elsewhere of Ishida’s multihead weighers.
Now, complementing a manual filling operation, the automatic
traysealing line has allowed Gastro Star to increase output
from just 7 trays a minute to 20. In fact, the machine itself is
capable of handling up to 36 trays a minute, and plans are in
hand to fully realise this output potential.
The speed capability could be higher still if modified
atmosphere packaging (MAP) were not required. But MAP
makes an important contribution to shelf-life extension
for many of the six salad variants, which include
ingredients such as croutons, lardons, egg or dressings.
The use of MAP makes particular demands and
imposes certain limitations of its own on any line.
It is only as effective as the heat seal that holds
it in place, so higher line speeds on the Ishida
unit had to go hand-in-hand with consistent
seal quality. The gas injection can not
only slow the operation
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down, but also risk blowing the light salad leaves into the
sealing area. In the case of the QX-775, controlled dosing of
the gas ensures that this type of disruption is minimised.
At the same time, every cycle, a sensor monitors the specific
gas mixture to ensure that it remains within specification.
Of course, lighter salad components can also be displaced
by the motion of the machine. The Ishida system addresses
this issue by using servo drives, ensuring that movement
and acceleration are smooth, while still maximising speed.
Filled trays are fed into the sealing unit in batches of three.
The servo technology comes into its own as the trays are
lifted up towards the sealing head.
Prior to sealing, the trays are filled by hand, having earlier
been loaded on to the non-slip, chain-operated line from a
double denester. Up to four operators deposit salad
ingredients in the trays. Each dosed tray is then automatically
weighed on an Ishida DACS checkweigher. Any requirement
for additional product is clearly flagged up on a digital display.
Once an accurate portion has been completed, a
secondary container is added to the tray.
This holds additional garnishes such as olives or
croutons (sealed to keep them crisp), a sachet of
dressing and a fork. It is important that the
salads, which are supplied to a major
Swiss retailer, constitute a complete meal
‘package’ for out-of-home consumption,
as well as offering convenience
in the home.
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Ishida Case Study Series: Gastro Star AG
It may also mean that film can be run at a lower tension,
which in turn helps to reduce tearing. Gastro Star project
manager Johann Meier calls this “a very handy feature”.
Overall, Ishida’s project management ran as smoothly as the
QX-775’s servo motors. Meier was certainly impressed with the
installation timetable, which began at 17.00 one evening and
was completed, with the equipment already operational, by
9.00 the following morning. After the obligatory safety checks,
the salad line swung into full production that same morning.
A fresh and appetising appearance is likewise essential.
After sealing and labelling, each pack undergoes visual
inspection to ensure it meets Gastro Star’s stringent quality
standards. Only then are the trays packed into cases.
Critically, Ishida designed the line with integrated controls and
a single touchscreen module for the denester, checkweigher,
traysealer and subsequent labelling unit. But finer points of
design can also have a profound importance for a customer’s
operation. The ‘Pull-back’ feature on the tray sealer is a case
in point.
Given the diversity of supply, film quality is never likely to be
quite as consistent as line supervisors would like it to be.
Consequently, there will be times when the top web does not
separate cleanly from the sealing tool. ‘Pull-back’ applies
reverse tension to the film, ensuring a clean break after sealing.
Ishida Europe Limited
11 Kettles Wood Drive
Woodgate Business Park
Birmingham B32 3DB
United Kingdom
Tel: +44 (0)121 607 7700
Fax:+44 (0)121 607 7666
[email protected]
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In fact, the project timetable as a whole more than satisfied
Gastro Star. Only weeks after the initial order, the line was
set up and ready for inspection at the Ishida plant. And of
course, the service provision post-installation will always be
just as vital a consideration. Meier enthuses: “An Ishida
technician stayed with us for another day and a half, and the
equipment has been working perfectly since then, just the
way one wants things to go!”
Finally, and especially when catering for evolving retailer
requirements, future-proofing is an increasingly important
element when planning a packing operation. In the case of
the Gastro Star salad line, for instance, the open design
means that any additional equipment or automation can be
managed through the same single control interface.
No one can predict what a new line will look like in five years
time. But it takes an experienced project manager like Ishida
to know which options it would be advisable to leave open.
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Ishida Switzerland
Tel: +41 (0)41 799 7999
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