Introduction applicable in other changeover situations at the
Frank Food Products (FFP) is a company
which operates in the food processing industry. The company produces various products
based on Soy or Lupine. The processing steps for soy or lupine concern
cleaning, toasting, de-hulling, milling and packing. Which process steps are taken
depends on the specific raw material and end product. Frank Food Products is
facing a high degree of complexity due to demand variation, a general increase
in demand, equipment changeovers, fixed production times and dedication of
production lines. The focus of this managerial advice is on the equipment
changeovers at toaster 2 (soy beans) and two mills (mill 5 and mill 6), which
at FFP take on average 1 hour. However, the advice could also be applicable in other
changeover situations at the plant.
SMED in process
Within the process industry, and at food
processing organizations such as FFP, changeovers can be a source of
manufacturing complexity. As mentioned by King (2009) the equipment in these
kinds of process plants are large and expensive, meaning that dedicating a line
to a product or product family
is not always economically viable. Therefore, changeovers are inevitable. Another
issue is the fact that changeovers in the process industry are often complex
not only due to mechanical changes, but also physics changes that are required.
An example of these changes is reaching a specific temperature for a specific product
(King, 2009). This often results in yield losses as reaching these product
specifications often takes a certain amount of time or raw material (Berry and
To cope with complexity concerning
changeovers, lean manufacturing tools could provide a solution for FFP. This is
somewhat contradicting as Lean tools are often used in discrete manufacturing
settings. However, as mentioned by Melton (2005), process industries can also benefit
from lean practices. This also holds for the lean practice of SMED (single
minute exchange of die). SMED seeks to identify internal and external
activities during a changeover and aims to transfer internal tasks to external
ones, resulting in shorter and more efficient changeovers (Ulutas, 2011). Mahapatra
& Mohanty (2007) show the importance of SMED in a continuous manufacturing
environment such as chemicals and foods/beverages plants. Through an empirical
case study, they evaluate different lean manufacturing tools in continuous
manufacturing plants and compere these to discrete manufacturing plants. It is
shown that SMED can play an important role in continuous manufacturing, sometimes
even more important than in discrete manufacturing (p24 table 5). Therefore,
also for frank food products, the lean practice SMED could be used to improve
the changeover process.
As mentioned by King (2009) changeovers in
the food processing industries can consist of mechanical tasks such as changing
the extrusion die shape or physics tasks such as bringing the line up to the
right temperature, viscosity, etc., when changing from one product to another. However,
concerning changeovers in the food processing industries, a lot of the time is also
spent on cleaning the equipment. All these tasks will be addressed and advice
will be given on improving the changeover process in next section.
Using SMED at Frank
1. Developing a value stream map of the
present state to determine at which processes SMED can have the greatest
impact. These are not necessary the changeovers that take the most time, but
can also be the changeovers that are prone to changeover losses such as
material losses, which often occur during changeovers in process plants. The
complexity concerning changeovers as mentioned by FFP lies in the toaster at
line 2 (soy beans) and two mills (mill 5 and mill 6), however, making a value
stream map can show FFP other locations that qualify for SMED.
2. To successfully implement SMED at
FFP, it is important to first analyze every activity that happens during the
changeovers at toaster 2 and mill 5 and 6. This gives insights in what can be
done outside the changeover window and can give an understanding in how the
tasks can be simplified, made shorter or if possible done in parallel. To get a
detailed insight in the changeover process, FFP could use multiple methods:
a detailed process map and timing diagram.
recordings to see what activities happen during the changeovers.
a point to point diagram which can give insights in the walking pattern of
operators and give the opportunity to reduce those by for example relocating
functional process maps to investigate which tasks during changeovers can be
done in parallel.
Within the process industry cleaning tasks are a
major part of changeovers. The cleaning tasks are also suitable for SMED
analysis. E.g. making sure that cleaning equipment is on the work floor before
shutting the line down or developing faster cleaning techniques.
4. One important concept within SMED is
making sure the tools and/or replacement parts (gaskets, filters, etc.,) are
already on the work floor before shutting the machine down. This is important
to make the changeover time shorter.
5. In process industries, after a
changeover, often a lot of time is lost in getting the line up to the right temperature,
viscosity, speed etc. Reaching this equilibrium can result in yield losses and
time losses. This probably also applies to the toaster at line 2 as this
process step consists of physics changes (heat). Therefore, it could be
interesting for FFP to organize structured brainstorming workshops. These kinds
of brainstorming sessions are important to come up with practical techniques
that can be used for more rapid heating or cooling of the toaster. It is
important that these sessions are held by personnel who have vast knowledge of
the toaster that is used in line 2. One could think of mechanical engineers, operators
or mechanics. It is also mentioned that these sessions have proven to be very
effective to develop new concepts that offer solutions for chemical and
physical problems concerning more complex SMED situations. Often successful
when done during a Kaizen event (King, 2009). Kaizen is an approach of
continuous improvement (Abdullah, 2003).
6. Finally, when the SMED process is
successfully implemented at FFP, it is important that the length of a
production campaign is re-evaluated, and if necessary shortened.
graphical example of an SMED improvement is given in appendix 1.