Top Banner
1 A Seminar presentation on Research of dynamic material handling in an automobile general assembly line based on real time information By: Devadas shenoy KP (4CB09ME014)
20

Research of dynamic material handling in an automobile general assembly line based on real time information

Apr 21, 2017

Download

Documents

Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Research of dynamic material handling in an automobile general assembly line based on real time information

1

A Seminar presentation on

Research of dynamic material handling in an automobile general assembly line based on

real time information

By: Devadas shenoy KP (4CB09ME014)

Page 2: Research of dynamic material handling in an automobile general assembly line based on real time information

2

Why research on material handling is necessary in manufacturing industry.

Modern high-technology manufacturing systems, such as those in the aerospace and automotive industries, can be more complex than ever before.

It is claimed that nearly 20%-50% of the manufacturing costs may be related to material handling.

Therefore, efficient and precise analysis of system performance in a general assembly line with material handling is necessary and important.

The assembly process synchronizes with the material delivery, so the necessary material delivered timely and accurate is the insurance of high productivity and quality.

Page 3: Research of dynamic material handling in an automobile general assembly line based on real time information

3

A general assembly line with a material handling system

Fig 1 : Architecture of material handling system

Page 4: Research of dynamic material handling in an automobile general assembly line based on real time information

4

Problems faced in material handling in an Automobile General

assembly line

Lack of real-time production information

Lower agility and frequency

Uncertain responsibility of drives

Page 5: Research of dynamic material handling in an automobile general assembly line based on real time information

5

Introducing Radio frequency Identification device (RFID) in the general assembly line

Real time production information tracking.

Consumption of line-side buffer is obtained dynamically.

The type and quantity of needed material are fed back to the subsystem of material handling.

Improves the efficiency of delivery drivers.

Page 6: Research of dynamic material handling in an automobile general assembly line based on real time information

6

What is RFID ?Radio-frequency identification (RFID) is the wireless non-contact use of radio-frequency electromagnetic fields to transfer data, for the purposes of automatically identifying and tracking tags attached to objects.

The tag contains electronically stored information which may be read from up to several meters away.

Unlike a bar code, the tag does not need to be within line of sight of the reader and may be embedded in the tracked object.

RFID tags are used in many industries. An RFID tag attached to an automobile during production can be used to track its progress through the assembly line

Page 7: Research of dynamic material handling in an automobile general assembly line based on real time information

7

Fig 2. Size of a RFID tag compared with rice grain

Fig 3. Working of RFID

Source : wikipedia.

Page 8: Research of dynamic material handling in an automobile general assembly line based on real time information

8

The architecture of the dynamic material handling system

Fig 4 : Working of RFID in automobile general assembly line

Page 9: Research of dynamic material handling in an automobile general assembly line based on real time information

9

Before introducing the specific steps of dynamic material handling system (MHS) based on RFID technology, the

situation of the assembly plant studied should be stated as follows.

The car body on assembly line continuously moving at a constant speed.

There is only one stocking area in the assembly plant.

Determinate number of delivery driver, limited capacity of dolly train to carry parts.

There is a predetermined set of parts for each driver’s responsibility.

Page 10: Research of dynamic material handling in an automobile general assembly line based on real time information

10

Demonstration of the specific steps of dynamic MHS based on RFID

technology.

Fig 5. The flow chart of material handling in the automobile assembly line.

Page 11: Research of dynamic material handling in an automobile general assembly line based on real time information

11

Determine the N_Threshold and the time windows of reorder parts

The dynamic MHS automatically calculates the collected part consumption information and adds a new reorder part to the reorder part list when its inventory level reaches the pre-set quantity which is called N-threshold.

The parts which the general assembly line needed should be delivered to stations based on the reorder point.

Reorder point is a pre determined criteria when a specific part reaches a certain level at its line-side buffer.

Generally, 15 minutes reorder point for part i at station j can sustain 15 minutes of production.

When the line-side inventory of parts is less than the pre-set quantity a part reorder request is sent to the material handling system automatically.

Meanwhile, a given number of drivers are waiting for the part reorder in the central docking area .

Page 12: Research of dynamic material handling in an automobile general assembly line based on real time information

12

The specific remaining quantity of part i, which is called N threshold, can be calculated as:

N threshold (i) = Reorder points/ Takt_time x Avg(i)…eq (1)

Where i denotes the part index.

Takt_time denotes the takt_time of the assembly line.

Avg(i) denotes the average consumption of part i, which can be obtained from historical production data.

Cont’d……..

Page 13: Research of dynamic material handling in an automobile general assembly line based on real time information

13

Identifying the departure time of deliver trips for a driver

As the automobile line is used in a Just in time (JIT) pattern, for a specific station, if the required materials arrive at the line-side buffer before its expected time, there may not be enough space for accommodating these parts and causes the cost of a vehicle waiting.

On the other hand, in order to avoid the case that the assembly line stops resulting from part starvation, it is required that the reorder part must be replenished before a certain time.

These problems strictly constrain the time of delivering the reorder parts.

Page 14: Research of dynamic material handling in an automobile general assembly line based on real time information

14

We define some notations:

RT i: the time when reorder part is added to the part delivery list.

BT i : the best time that the inventory level of the line-side buffer just reaches the safety stock when the reorder parts are replenished.

LT i : the latest time the reorder part arrives at the station, when the inventory of a line-side buffer becomes exhausted. C i : The consumption rate of part i.

IL i : the inventory level of part i .

OR i : the amount of part i which is on road to the station.

Then,LT i = RTi + (ILi + ORi )/ Ci………eq (2)

BTi = + (ILi + ORi - SSi)/ Ci……….eq (3)

Page 15: Research of dynamic material handling in an automobile general assembly line based on real time information

15

Determining time windows of reorder parts.

Once the part is added to the part delivery list, the time window can be obtained which is [RT i, LT i]

we introduce the timeliness penalty function for measuring the degree of timeliness of a delivery activity.

As shown in Figure 4, we penalize the deviation of the part replenish time from the BT i , the timeliness penalty gets the value of zero at the best time and positive values at other points.

The slope of the penalty function is α, β, and the big M for the replenish time belonging to the interval [RT i, BT i] , [BT i, LT i] and [LT i, ∞], respectively.

The proper values of α = - 0.5 and β=2.5 are obtained from computational experiences.

Fig 6 : Time window of the part reorder station

Page 16: Research of dynamic material handling in an automobile general assembly line based on real time information

16

Numerical resultsBased on the above analysis, considering there are 238 parts and 6 drivers involved in the delivery activity, before parts being delivered to assembly stations,

Each driver is arranged in charge of a set of parts which he should replenish. Based of the 32 shifts of dynamic material handling planning for the automobile assembly plant,

The comparison results of the proposed improved material handling method (IMHM) and traditional material handling method (TMHM) are shown in Table 1.

Compared with the traditional material handling method, the frequency of driver’s delivery trip of the IMHM decreases remarkably

The results shows that the IMHM is more practical than TMHM and can supply the necessary material for the automobile assembly plant in time, and remarkably improve the efficiency of the driver.

Page 17: Research of dynamic material handling in an automobile general assembly line based on real time information

17

Driver TMHM

(times)

IMHM

(times)

Reduce

(times)

TMHM

Busy time

(min)

IMHM

Busy time

(min)

Save

(min)

1 3574 2905 669 15793.96 15056.11 737.85

2 3581 3480 101 17335.06 17230.69 104.37

3 3081 1614 1467 8772.89 5554.07 3218.82

4 3439 2329 1110 14152.86 12676.47 1476.39

5 2396 1918 478 13229.32 12774.36 454.96

6 3323 3274 49 19013.48 18950.19 63.29

The comparison table results.

Page 18: Research of dynamic material handling in an automobile general assembly line based on real time information

18

ConclusionsIt is based on RFID technology to achieve the real-time tracking of assembly status information.

Different from the traditional material handling method which is periodic and under the delivery strategy of one dolly one trip,

The dynamic material handling system automatically obtains the consumption of a line-side buffer.

According to assembly information and time windows of the needed material, it determines the best time of delivery driver to start the trip based on total time penalty function.

Numerical testing results of a practical automobile assembly line show that the new method is efficient and effective,

The material amount of a single delivery trip is maximized

Page 19: Research of dynamic material handling in an automobile general assembly line based on real time information

19

REFERENCES

[1] Li J, Meerkov S M, Production systems engineering. Springer , NewYork,2009

[2] Li J, Blumenfeld D E, Huang, Alden J M, Throughput analysis of production systems; recent advances and future topics. International Journal of production research, 47(14);3823~3851,2009

[3] aedavan A V, Gilbert L, Loop based facility planning and operation research, 164;1~11, 2005

[4] cao Z X, Zhu Y L, Research on material feeding and its implementation in general assembly line of mixed model automobile. Computer integrated manufacturing systems,12(2); 285~291,2006(in Chinese)

[5] Qui WP , Shi H B, Shang W L, The partfeeding management methodology for mixed model automotive assembly line. Machinery design and manufacture, 1;138~140, 2008(in Chinese)

Page 20: Research of dynamic material handling in an automobile general assembly line based on real time information

20

Thank You