OPTIMIZATION OF LIGHT TRANSPORT
VEHICLE ENGINE DECKING CYCLE USING SIMULATION TECHNIQUES
1
ABSTRACT
Engine
decking process is one of the most critical process in final assembly line of
light transport vehicle (LTV maxximo, 2Cylinder CRDe engine with DOHC
technology 4Valve/cylinder Power-25HP, 45NM torque ,850kg payload ,900CC
engine) of Mahindra .Painted bodies with chassis passed to final assembly lines
on conveyers where different vehicle components are attached to it such as
doors, cargo radiator, instrument panel , wind shield glass ,engine, axle,
steering gear box, wheels, batteries etc.
In engine decking process, Engine is
attached to the body of LTV. Engine placed on self propelled engine trolley
which moves on circular conveyer in closed loop and attached to body of LTV
which is hold by electro monorail sensor hanger (EMS).earlier in this process assembly workers moves with line process
speed and do all assembly work of engine attachment to the body i.e.
positioning of engine on trolley, alignment of engine, torquing of engine with
chassis etc. This process is inconvenient
for assembly workers considering
ergonomic point of view. Output in terms
of JPH (jobs /hr) were not also achieved
consistently. in this paper new process
for engine decking has been
designed by considering ergonomic point
of view, with changing EMS hanger speed at different stations on assembly line
and providing stop for engine assembly on vehicle body.Time for which engine on
trolley is stopped is known as engine decking cycle time.That time is optimized using simulation techniques.
2 INTRODUCTION
VDI (Verein Deutscher Ingenieure,
Association of German Engineers) guideline 3633 defines simulation as the
emulation of a system, including its dynamic processes, in a model one can
experiment with. It aims at achieving results that can be transferred to a real
world installation. In addition, simulation defines the preparation, execution
and evaluation of carefully directed experiments within a simulation model.
Developing your simulation model is a
cyclical and evolutionary process. You will start out with a first draft of
your model and then refine and modify it to make use of the intermediary
results the simulation runs provide. Eventually, after several cycles, you will
arrive at your final model.
2.2Time-Oriented Simulation and Event-Oriented Simulation
Plant
Simulation is a discrete, event-oriented simulation
program, i.e., it only inspects those points in time, at which events take place
within the simulation model
A
discrete, event-oriented simulation program on the other hand only takes points
in time (events) into consideration that are of importance to the further
course of the simulation. Such events may, for example, be a part entering a
station or leaving it or of it moving on to another machine. Any movements in
between are of little interest to the simulation as such. It is only important
that the entrance and the exit (Out) events are
displayed correctly. When a part enters a material flow object, Plant Simulation calculates
the time until it exits that object and enters an exit event into the list of
scheduled events of the EventController
for this point in time.
Thus,
the simulation time that the EventController
displays, leaps from event to event. This happens as soon as an event is
processed.
“To
change the existing process of engine
decking in which all these assembly operations worker has to move with conveyer
and fitting engine on body. For whole shift it was difficult for worker to
aligning of engine , torquing etc. Task is to develop new method convenient to
assembly workers and achieve desired output in terms of JPH.(jobs per hour)”
.In new method, engine on self propelled trolley will stop for assembling with
vehicle body at station with some time known as engine decking cycle time. We
have to optimize that time with the help of simulation. following are some of
task for that we have to use simulation techniques.
·
Validate
Stop and Go Concept for Engine Decking process
·
Validate/predict
System throughput
·
Validate/optimize
Engine Decking Operation cycle time
·
Optimize
EMS Hanger Speed
·
Optimization
Engine trolley
·
What-if
analysis
·
4 METHODOLOGY
Tecnomatix Plant Simulation
provides these objects for simulating the flow of materials through a plant:
·
The EventController
for coordinating and synchronizing the events taking place during a simulation
run.
·
The Frame
as the container for creating your simulation models. It might, for example,
represent a complex machine, a part of an installation, or the entire plant.
·
The FlowControl
for modeling common strategies for splitting-up and bringing together the flow
of materials.
·
The Transporter
for
modeling self-propelled vehicles allowing it to drive on its own on a Track
and to transport parts.
5 MODEL
Fig.1 simulation
model for engine decking
Fig.2 SIMULATION MODEL
USING TECHNOMATICS PLANT SIMULATION SOFTWARE
6 RESULTS AND ANALYSIS
6.1 SCENARIO 1
Table.1
6.2 SCENARIO 2
Table 2
6.3 SCENARIO 3
Table 3
6.4 SCENARIO 4
Table
4
6.5 ENGINE TROLLEY QUANTITY OPTIMIZATION
Table 5
6.6 Hanger Speed Vs
decking cycle time analysis
Table 6
7 CONCLUSION
Engine decking process is
the process in which engine of LTV is attached to the body of vehicle. With the
help of discrete event simulation we able to change process of engine decking.
In earlier process assembly workers has to move along self propelled engine
trolley and EMS (electro monorail
sensor) hanger and engine from engine trolley is assembled to the body of the
vehicle. But this process was inconvenient to workers ergonomic point of view. Using discrete event
simulation we able to make go and stop concept for engine decking so that
engine on self propelled trolley will stop for time equal to engine decking
cycle time at station five . Within that
decking cycle time worker will do all operation related to engine decking
process.
We
have find following using discrete event simulation
} The optimum engine decking operation
cycle time is 2 min 20 second with hanger speed 12 m/min(station 4,5,6).
} Hanger speed between station between 3
& 4 ,4 & 5 and 5 & 6 is 12m/min
} By decreasing the hanger speed at station
4,5,6 the decking cycle time(at station 5) is decreasing
} At 6 m/min of hanger speed the best decking cycle time
is 1 min 55 sec at station 5
} Optimum number of engine trolley is 3
8 REFERENCES
1.
Averil
M. Law (2008)-Simulation modeling and analysis,TMH,Bostan USA
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