. . 2556 16-18 2556

: 5.56 .

Breakdown Time Reduction by Applying Preventive Maintenance

:Case Study Primer and Anvil of 5.56 mm. Cartridge Making Process

1* 2

E-mail: orddept@hotmail.com

Karun Chaivanich1*Bodin Singpai2

Department of Ordnance Engineering, Chulachomklao Royal Military Academy, NakornNayok E-mail: orddept@hotmail.com

5.56 .

(Pareto Diagram)

5.56 .

(Failure Mode and Effects Analysis; FMEA) (Fishbone Diagram)

(Preventive Maintenance Plan) 480 / /

67.89% 319 / / 66.46%

(MTBF) 182.74% (MTTR)

11.61% (Availability Rate) 5.79%

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Abstract

An objective of this research is to reduce the machine breakdown time in the process of 5.56 mm. cartridge�s primer and anvil making by applying the preventive maintenance plan. Methodology of the research is started

by selecting the machine that has a priority for improvement by applying the Pareto diagram. Downtime rate is used as a criterion in order to consider the priority. Maintenance records are used to find out a relationship

between machine�s failure and parts. Then the Failure Mode and Effect Analysis (FMEA) and the Fishbone

diagram are applied to point out the problems, potential cause, and preventive action. Finally, the studied factory follows the preventive maintenance plan and does the maintenance record for further studying. As the

result, the stamping machine has the highest breakdown rate which is 480 minutes per machine per month or 67.89%. After the preventive maintenance implementation, the averaged breakdown time is reduced by 319

minutes per machine per month or 66.46%, the Mean time between failures (MTBF) is increased by 182.74%, the Mean time to repair is increased by 11.61%, and the Availability Rate is increased by 5.79%. In

conclusion, the preventive maintenance plan is implemented at the factory and it can reduce lose in term of machine breakdown, and also increase the availability rate and operating time of machine before failure.

Keywords: Breakdown Time, Preventive Maintenance, Pareto Diagram, Failure Mode and Effect Analysis,

Fishbone Diagram

1.

(Maintenance System)

5.56 .

1.

(Breakdown Maintenance)

2.

3.

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(Breakdown

Time)

2.

(Preventive Maintenance Plan)

2.1 (Pareto Diagram)

[1]

2.2 (Fish Bone Diagram)

(Effect) (Cause)

(4M)

3 1.

2. 3.

2.3

(Failure Modes and Effects

Analysis; FMEA)

FMEA

(Potential Failure Mode)

(Potential Effect)

FMEA

1. (Process Flow)

2. 3. (Failure

Mode) 4.

(Cause of Failure Mode)

5. (Effect)

6. (Severity; S)

7. (Occurrence of Failure

Mode; O) 8.

(Detectability of

Cause of Failure Mode; D) 9. Risk Priority Number (RPN) = S x

O x D FMEA

RPN

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RPN RPN

FMEA RPN

[2]

2.4

[3]

2.4.1

[4]

2.4.2

2.4.3

2.4.4

(CBM)

(TBM) [5]

3.

3.1

5.56 .

1.

2.

3. 4.

1

1

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2

3.2

2

3

1

3.3

3

1

3.4

480 158 42 27

67.89%

90.24% 96.18% 100.00%

0%

20%

40%

60%

80%

100%

0

150

300

450

600

750

( / / )

Punch

Die

. . 2556 16-18 2556

2

2

4.

5.56 .

2 67.89%

5.56 .

319 / / 66.46%

(MTBF) 182.74%

(MTTR) 11.61% (Availability Rate)

5.79%

5.

3

(+) , (-)

( / / )

480 161 - 66.46%

MTBF ( ) 90.28 255.26 182.74%

MTTR ( ) 128.96 143.93 11.61%

Availability Rate (%) 86.90 91.93 5.79%

3

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[1] . 2550. . ( - ),

. [2] . 2551. FMEA

.

( - ), . [3] . 2546.

. , . [4] , ,

.

. 2554,

, , 20-21 2554: 1631-1638.

[5] . 2550.

. , .