4. Real applications and results
The developed integrated system has been applied to two different
real cases regarding respectively a distribution center of
goods for the fashion industry and a supermarket warehouse for
the parts feeding for a mixed model assembly system. These two
applications have permitted to test the system in a wide range of
warehousing activities, from the simple retrieval of goods inside
stocking area to the packing of shipping box. Moreover, the handled
pieces were characterized by different dimensions, small
items or long and big ones.
Some important considerations have been carried out and the
validity of the system has been demonstrated, both for its use as
tool assisting the engineers during the design process of warehouses
and for the feedback in real-time to workers avoiding the
operations in awkward postures.
4.1. Distribution warehouses: refilling, picking and packing activities
The first case deals with a distribution warehouse for the fashion
industry, where a great number of varieties of small goods are
received from the producers. After a quality control phase, the
pieces contained in small SKU are stored in a specific stocking area.
The objective of this area is to optimize the storage capacity. Then,
these pieces are retrieved in a well-defined amount (not in boxes
but in the exact required items) from this area to refill the empty
locations situated in the picking area. This last zone is smaller than
the first one and it contains fewer pieces for each item. In fact, in
this area, the main objective is to maximize the throughput of
the warehouse, minimizing the travel time spent to pick the items
required by a shipping order list. Here the shelves have 7 levels at
different heights from the ground. At the end, the picked goods are
placed inside the shipping box with the selling cases. This activity
is performed in a fixed workstation. In both stocking ad picking
area, the storage allocation strategy was random, without any consideration
about the item movements items (Battini et al. 2012a;
Battini et al. 2013). All the transportation activities from the stocking
area to the picking zone are manual with particular big carts
pushed by the operators. These carts cannot be used inside the
aisles, so the operators leave it in a fixed position outside the storage
area and go forwards and backwards to pick or to store the
required SKUs or items, involving in an increasing travelled distance.
After the refilling, the empty SKUs are pushed away in a garbage
zone. From the picking area, the pieces are hand-carried with
several problems about the maximum amount of transported
pieces.
In this context, the objective of the project has been the redesign
of the whole warehouse improving the productivity and