Thus, a big opportunity exists now in the market,
because several of the challenges involved in
optimizing production are not well addressed or not
addressed at all. Especially the part of aggregating
data from the shop floor and use it for real-time high-
level automated decision making is not addressed.
The aim of this work is to provide intelligent
decisions in real-time in order to increase flexibility,
efficiency and predictability in manufacturing. The
expected outcome is to build a real-time planning
solution that works in a production scenario with high
complexity and high mix of products.
2 RELATED WORKS
Traditional scheduling approaches in production
involve the creation of schedules prior to beginning
of the production process. In this case, uncertainties
that are not expected nor taken into account at the
planning phase can cause delays of these schedules
(Suwa et al., 2012). Common uncertainties that occur
in a manufacturing system include machine operator
absence, material shortages, and machine failure
(Snyman et al., 2017).
In such scenarios, the manager has to react by
manually selecting a new or revised schedule to
ensure that production continues while maintaining
the required performance level. All these challenges
lead to poor utilization of resources, delays in
deliveries and sometimes chaos in production.
The innovation of real-time scheduling is to
address the shortcomings of the traditional
approaches by performing scheduling concurrently
with the production process. Furthermore, based on
the analysis of historical data, it is possible to predict
maintenance activities and include them in the
scheduling. This new approach can help industries to
better plan activities (e.g., reduce waste, improve
productivity) and mitigate the risks of non-delivering,
especially in OKP companies in which the
uncertainties are more frequent.
The characteristics of OKP make production
scheduling and control extremely difficult (Tu et al. ,
2000). The main featuresof the OKP production are:
high customization (each product is designed and
manufactured based on customer requirements),
complicated and dynamic supply chains, great
uncertainties in production control and dynamic
production systems (Luo et al., 2011). In OKP
manufacturing, due to high customization, the
productive cycle does not repeat and the productive
tasks do not have fixed times (Tu et al., 2000).
In addition to the dynamics just mentioned, there
are also other disturbances such as stochastic
customer orders or emergency orders, and frequent
engineering changes, that make highly complex the
productive activities planning (Lu et al., 2006).
The proposed framework is a MES
(Manufacturing Execution System), i.e., a software
product able to manage factory floor material control,
and labor and machine capacity, and to track and trace
components and orders, manage inventory, optimize
production activities from order launch to finished
goods (Helo et al., 2014). A similar study was
proposed by Wang et al. (2012), who developed an
application of a RFID enabled real-time
manufacturing execution system for OKP
manufacture of radial tire mold. This study
demostrated that the atomatic workshop control
system largely improves the machines’ utilisation rate
and thus the production efficiency. In this way, the
production potentials of the company can be
exploited fully though the real-time information,
instead of being directed arbitrarly by managers.
Furthermore, our proposed system schedules
activities through the product input data and changes
the planning depending on the unexpected events to
respect, anyway, the deadlines. It also controls the
tasks status, the downtimes (due to breakdown,
maintenance, etc.), the operations in production
support (material handling, program loading, quality
control, etc.). It can also compute, through the
analysis of data, the KPIs relative to the production.
3 MES SYSTEM FRAMEWORK
The developed framework consists of several
software applications and hardware components,
produced by the Octavic PTS company
(https://octavic.dk/). The framework is useful for
bridging data from operators with machine data to
offer contextualized data (human driven data) for all
the levels in the organization. This approach gives
better insights about the root cause of the problems,
actions that have been made and provides real-time
feedback for the decision makers.
The machine data is automatically communicated
to the system (IOT technology). A practical example
of integrating operator data with machine data is
when the machine is stopped for the loading of new
equipment. In this case the operator communicates
the start and the nature of downtime to the system
while the end is automatically recognized by the
system thanks to the machine information. These last
report to the system when the spindle stops or moves.