Automated warehouse for an integrated, proactive and safe supply chain, Kaj Fahllund. Vice President, Pulp & Paper, Pesmel

PAPERTECHNOLOGYINTERNATIONAL
Figure 3: See the summary of
main characteristics of different
warehouse types used in paper
mills and converting plants:
The reasons for automation are now changing due the
megatrends explained above, which are accelerating the change
towards automation. It’s not about volume management anymore,
it’s about how to deliver products faster, with more flexibility, and
ultimately cutting costs across the whole supply chain. In other
words: how to change the reactive supply chain to be proactive, how
to be able to react faster to changes in the market and customer
demands.
Key features to be compared
A supply chain model means how mills are producing and
distributing specific products to their customers. Common practice
used to rely solely on reactive “Make to Order” (MTO) model, where
manufacturing is driven by orders. But if you want to excel with
speedy deliveries, beat your competitors by weeks with reduced
lead times from order to delivery, you also need to be able to
manage the “Made-to-Stock” (MTS) model from a single warehouse,
not from a distributed network of warehouses. This defines the
key features that automated warehouse needs today, and why
manual work in warehouses is disappearing. It’s about the density
to be able to store needed volumes (tons) in one warehouse within
available space at the mill, as well as handling capabilities to able
to manage the mixed content to ensure short turnaround times for
transportation logistics.
The differences between handling and sorting capabilities
are explained by how rolls are handled through the warehouse.
Deep channel high-bay warehouses are handling the rolls in sets,
compared to other alternatives which handle single roll or pair of
rolls at once. When you handle 2-6 roll sets per cycle, instead of one
roll, you have 2-6 times bigger handling capacities per equipment.
This also lowers the overall need of equipment in the system
accordingly.
And the big difference in storing density is explained partly
with the maximum roof heights different concepts allow. Flexible
high-bay rack storages can be anything between 10 and 40 meters,
when overhead crane storage heights are limited to 25 meters
and AGV and manual PIT warehouse to 10 meters. The abovementioned handling capacity affects to the storing density too. When
you have enough handling capacity to reorganize your inventory,
you can store also mixed sets. This reflects directly to the practical
fill rates different solutions can manage. The fill rate in HBW deep
channels is 85%, with overhead cranes it is 70% and with AGV and
manual PITs 50% due to the driving aisles.
Total cost of ownership defines the most cost-efficient
alternative for both, big and small volumes
Selection of the right warehouse type depends on many
issues which vary case by case. These are preferred supply chain
model, produced grades, location, surrounding infra and so on.
There is no “one-size-fits-all” solution available. But what is clear,
is t that the most important fact in the selection is the total cost of
ownership, comprising both the capital and operational expenses.
Also costs, which are difficult to measure, such as improved safety
with zero-accident-zones and competitiveness achieved against
the competitors with more resilient and agile warehouse operations
make a difference. In the text below, two reference cases are
introduced, along with how their unique needs and challenges were
solved through automated warehousing.
Case Mondi Štětí: Shipments organized by automated
warehousing
A customized automated sorting buffer has been installed at
Mondi’s new 210,000 metric ton per annum kraft paper production
line in Štětí, Czech Republic. “Every warehouse has its own
purpose. In the case of Mondi Štětí, it is not to store but to organize,”
says says Jani Matikainen, Sales Manager at solution provider
Pesmel.
The new production line is intended to meet growing
demand for paper-based, flexible packaging and has started up
production in December 2024. The system supplied by Pesmel
includes an automated roll warehouse (ARW) with a 3,000 metricton capacity for buffering sack kraft paper rolls. The incoming roll
flow is first pre-sorted on sorting channels, from where stacker
cranes pick-up and store rolls on storing channels. This two-step
flow ensures high flexibility, along with full redundancy and re-routing
capabilities.
“Daily production is about 600 tons per day, so with five
days’ worth of storage this has a shorter turnover rate compared to
some facilities we have worked on,” continues Matikainen, “and it
fills a need that would be almost impossible to meet manually or with
other alternatives within such a limited space.”
A 32-meter-high deep-lane rack warehouse serves as
shipment storage, operated by two stacker cranes enable a high
storage density crucial in an area with limited space but with very
high roll flow.
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