All Tutorials - Lab - Lean manufacutring PDF

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WORKFORCE MANAGEMENTA packaging shop floor consists of three machines and produces three types of products. There is a dedicated machine to each type of part. The machine processing time is 10 minutes and parts arrives into the shop floor based on an exponential distribution exponential (0,10,0) min...

Description

WORKFORCE MANAGEMENT A packaging shop floor consists of three machines and produces three types of products. There is a dedicated machine to each type of part. The machine processing time is 10 minutes and parts arrives into the shop floor based on an exponential distribution exponential (0,10,0) minutes. Currently an operator is involved in transferring the product from the initial inventory area to the three machines. The shop floor manager in order to increase throughput decided to simulate the shop floor and experiment with multiple operators and find out the optimum number of operators for an increased throughput.

Machine1

Source

Buffer

Machine2

Machine3

Figure 1, Material Flow

Sink

Resources Utilization & LEAD TIME ESTIMATION Problem Statement: An aircraft component manufacturing company produces mainly 5 types of aircraft structural components. Most of the customer orders at the company are of low volume and expensive. The objective is to find the lead time to satisfy each order and the utilization of resources. The manufacturing assembly comprises of 9 work centres which are used to manufacture the components and there is an infinite supply of raw materials for these machines to produce the components. The production material flow diagram is given below.

Figure 1, Material Flow

Once the parts are manufactured a Forklift is used to transfer parts from the Machine 1B to the order packaging area with a processing time of 10 min. An operator is used to transfer parts from Machine 2B, Machine 3A and Machine 4A to the packaging area and another operator is used to transfer parts from Machine5B to the packaging area. The same operator operates Machine 5A also. The processing time of the machines is given below. Machine Name Machine 1A Machine 1B Machine 2A Machine 2B Machine 3A Machine 4A Machine 5A Machine 5B

Processing Time 7 min 9 min 8 min 2 min 1 min 6 min 5 min 2 min

Table 1, Processing Time

The order arrival table and the product mix table for each orders is given below.

Order Number 1 2 3 4 5 6 7 8 9 10 11 12

Order Arrival Time 8:50 8:50 8:50 11:20 11:20 11:20 15:30 15:30 15:30 21:20 21:20 21:20 Table 2, Order Table

Order Num 1 2 3 4 5 6 7 8 9 10 11 12

Product A 4 2 3 4 1 2 1 0 1 1 2 1

Product B 3 2 4 3 3 2 4 2 3 1 4 3

Product Name Product C Product D Product E 2 4 3 2 2 2 1 2 3 2 4 0 4 1 2 3 2 1 1 0 0 4 4 0 2 4 2 1 2 3 3 2 1 0 4 1

Total Quantity 16 10 13 13 11 10 6 10 12 8 12 9

Table 3, Product Mix Table

The packed orders are transferred outside the plant using a straight conveyor with a speed of 2m/min and the buffers just before the machines have a capacity of 10 units. The forklift and human operators also travel with an average speed of 2m/min in concern of safety.

P age |2

U-LAYOUT VS LINE LAYOUT PRODUCTION An automotive die making making company produces dies for casting. The die is made in a single line layout. The manufacturing process mainly involves forging and heat treatment which takes a time of 45 minutes and 120 minutes. There is a single operator involved in operating two machines. However, the operator felt that if the machines are positioned closer he can easily operate the two machines. He complained this discomfort to the owner of the factory. Empathising the difficulty faced by the operator the owner decided to reposition the layout and thought of making the layout as a U-layout. Before doing such an experiment he wants to ensure it, so he approached a simulation consultant to exercise this option. His objective was to compare the throughput of the two layouts and the distance travelled by the operator. The raw material arrives every 10 minutes and buffer capacity is 1000 units.

Source

Buffer1

Forging

Buffer2

Figure 1, Material Flow

Heat Treatment

Sink

PUSH VS PULL PRODUCTION A fire cracker manufacturing company produces mainly 5 kinds of crackers. The cycle time of production is exponential (10, 2, 1) minutes. Currently the company employs push production system and the raw material arrives every 8 minutes. The shop floor manager wants to reduce the unfinished and finished raw material inventory by implementing a pull based production. In other words, the production is started only when the order is received. Create a simulation model which has both push and pull based production and compare the throughput and inventory. Source

Stock1

Machine Figure1, Material Flow

Stock2

Sink

LINE BALANCING A personal consumer goods manufacturing company produces mainly 3 kinds of products. The raw materials arrive at the company on an average time of 5 min with a standard deviation of 0.5 minutes. There are three machines for manufacturing and each product is having a dedicated machine. In other words, product type1 will only go to machine1, product type 2 to machine 2 and product type 3 to machine3. The time taken to manufacture a product is 10 minutes in all the machines. After manufacturing the products go to a testing station where it gets tested. The rejection percentage of the testing area is 10 %. The rejected products move back to the initial raw material inventory. During the peak seasons, they always have an increase in demand by 15 %. So they tried to push 15 % more material into the layout by decreasing the inter-arrival time by 15%. But they couldn’t increase the throughput by 15 %. The industrial engineering team wants to increase the throughput by 15 % by conducting a study using simulation. Conduct the simulation study over a period of 4320 minutes.

Machine1

Source

Machine2

Machine3

Figure1, Material Flow

Tester

Sink

BATCH VS SINGLE PIECE PRODUCTION SYSTEM A bakery produces cakes in its manufacturing area. The mix of the cake enters into the manufacturing area following an inter-arrival time of exponential (0, 10, 0) minutes. The baking of the cake in the oven takes approximately 10 minutes. The shop owner has a space to put 4 cakes in the baking area for baking. So he thought of experiment the manufacturing via a batch based production by putting 4 cakes at a time in the baking area in a pan for increasing the throughput. Before implementing in the layout, the owner wants to check this idea via a simulation through his friend, who is a consultant in simulation. The objective here is to compare the throughput of batch and single piece production system via a simulation tool. Source

Queue

Baking Figure1, Material Flow

Sink

PREDICTIVE MAINTENANCE An automotive spare manufacturing shop floor manufactures mainly four types of parts. There are total 4 machines dedicated to each part type. The parts after manufacturing are tested at a testing station. The rejection percentage at the testing station is 20 %. The rejected parts are routed back through the manufacturing machines for rework. The parts arrive to initial inventory area on an average of 5 min with a standard deviation of 0.5 min. The volume distribution of parts are given below in the table. Part Type 1 2 3 4 Total Percentage

Volume Distribution 20% 30% 40% 10% 100% Table 1, Volume Distribution of Parts

Machine1 Machine2

Tester

Source

Sink

Machine3

Machine4

Figure 1, Material Flow

Parameters Source, Inter Arrival Time Machine1, Process Time Machine2, Process Time Machine3, Process Time Machine4, Process Time Testing Machine

Value Normal(5,0.5) min 10 min 10 min 10 min 10 min 4 min Table 2, Data

The shop floor manager have some ideas to increase the throughput of the system by increasing the capacity of the testing machine and by pushing more products by varying the arrival time. He listed out his ideas in a table which he called the scenario table and wants to study it through simulation before implementing it. The scenario table is given below. Variable Scenario1 Scenario2 Scenario3 Scenario4 Max Content Tester 1 2 3 4 5 4.75 4.5 4 Arrival Time Table 3, Scenario Table

RESOURCE CAPACITY VALIDATION A conveyor system manufacturing company wants to demonstrate the working of a proposed cross belt sorter conveyor system to a manufacturing facility before actually erecting the conveyor system in the facility. The manufacturing team proposed to develop a simulation model which shows the working of the conveyor system and evaluate its performance. Also the manufacturing team needs to find out the throughput of the system over a duration of 1000 minutes. There are mainly four kinds of parts sorted by the system. A source sends material to the conveyor system through a machine. The inter arrival time of the source is exponential (0, 5, 0) minutes and the processing time of the machine is 2 minutes. The conveyor system comprises of 8 straight conveyors, 2 straight dogged interval conveyor and 2 curved dogged interval conveyor. The conveyor parameters are given below. The start and end straight conveyors can only take one kind of part. Conveyor 8 Nos, Straight Conveyor 2 Nos, Dogged Straight Conveyor 2 Nos, Dogged Curved Conveyor

Speed 1 m/minute 1 m/minute 1 m/minute

Length 10m 12.09m Radius 2.59, Sweep Angle-180

Table 1, Conveyor Parameters

Source

Queue

Machine Figure1, Material Flow

Conveyors

Sink...