Modelling, Simulation and Optimization of a Packaging and Palletizing System

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machine, pick and place unit, different types of conveyors etc.

Technical data: turntable max. rotation speed:15 r.p.m; height table top: 370 mm; max. pallet

dimensions: 1200 x 1400 x 2100 mm (W x L x H); max. loading capacity: 2000 kg; production

capacity: 25-30 pallets/hour; max. height of the film roll: 500 mm; max. diameter of the film roll:

300 mm; photocell for the automatic pallet height detection [2]

Other system’s components

C1 conveyor is a belt conveyor used in the food industry. Technical data: max. load capacity: 20

kg/m; speed range between 0.10 to 0.50 m/s; motor type: shaft-mounted gear motor; diameter of

drive roller: 63 mm; belt with 2-layer polyester fabric with PVC coating, smooth.

C2 and C3 conveyors are powered roller conveyor for the boxes transportation. Technical data:

max. load capacity: 50 kg/m; speed range between 0.1 m/s to 1.3 m/s; roller diameter: 50 mm.

206 Advanced Technologies in Designing and Progressive Development of

Manufacturing Systems

C4 and C5 are pallets conveyors with max. load of 1500 kg; speed range between 0.15 m/s to 0.3

m/s and lane widths up to 1500 mm. [3]

The Forklift has the flowing characteristics: load capacity: 1600kg; lift height: 3205 mm; travel

speed 19 km/hour; speed without load: 0.60 m/s; lift speed with load: 0.40 m/s; aisle width for

pallets 800 x 1200 lengthways: 3589 mm.

Case Study

In our case study, in the packaging and palletizing system the coffee bags that will be packed in

boxes represent the products. Each bag of coffee has 96x47x195mm (LxWxH) as shown in Fig. 2 a.

The coffee bags are found initially in the local storage system (B1). The coffee bags are transported

to the packaging work point using the C1 conveyor. The C2 conveyor is transporting the boxes from

the local storage system (B2) to the packaging work point (Wp1). The box size is 300x200x400mm

(Fig. 2 b.). The coffee bags will be arranged 12 on the first and second level, in the 3x4 structure, as

shown in Fig. 3.

In the boxes coffee bags will be packed, each having 500g, each box will contain 24 coffee bags,

resulting in a weight of 12 kg/box.

Fig. 2 a. The coffee bag size, b.The box size

The robot (R1) takes the coffee bags from the transport system - a belt conveyor type (C1) - and

it will transfer the coffee bags to the packaging work point (Wp1). R1 will put the coffee bags in a

specified position in the box, using the planned loading program.

Fig. 3 Layout of the coffee bags in the box

After packaging, R1 will transfer the box on the C3 conveyor. The conveyor (C3) transports the

boxes to the wrapping work point (Wp2).

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The pallet is transported from the local storage system (B3) to the wrapping work point using the

C4 conveyor. We chose to use the standard pallet with the size of 800x1200mm. The robot (R2)

takes the boxes from the C3 conveyor and transfers them to the pallet using a defined palletised load

program. The pallet is positioned on the wrapping machine table. On the first pallet level 16 boxes

will be positioned, as shown in Fig. 4, the stack will consist of 4 layers, resulting a total of 64 boxes,

a height of 1600mm and a mass of 768kg. Adding the pallet own mass of 50kg will result in a total

weight of 818kg. The layers will be rotated by 1800 for the stability of the stack.

After placing all the 64 boxes on the pallet, the stack will be wrapped. The wrapping machine

has rollers that will transfer the pallet directly to the C5 conveyor. For storage, the forklift will take

the pallet from the C5 conveyor and will transport it on the central storage system.

Fig. 4 The arrangement of boxes on the pallet

We consider the packaging and palletizing system as a diffuse processing system because it

includes several work points connected by transport & transfer systems and using storage systems at

local and system level [4]. We used the FlexSim 7 virtual prototype simulation for this system

optimization in terms of productivity. We have modelled the components of the packaging and

palletizing system using the database available in the FlexSim 7 simulation software. For the virtual

model the links between the system’s structural elements were created using the system real

parameters in order to reproduce the material flow trajectories. Then, using this virtual model, a

simulation was performed to identify the bottlenecks and the long waiting times from the system. In

the preliminary simulation, the parameters for system’s components were set to their default value.

For each type of a processed product, the simulation will start from these default parameters of the

system. Those parameters will be modified in successive simulations until will be obtained an

optimized version of the system in terms of productivity.

The