This document summarizes a Lean Six Sigma Yellow Belt project conducted by Mutiara Dari Timur to reduce the weld repair rate at an engineering company from 15.5% to 5%. Key aspects of the project included defining the critical quality factors, creating a SIPOC diagram and defect proportion table, analyzing the defects using a Pareto chart and cause-effect diagram, implementing a 5S program and new welding procedure to improve processes, and verifying the reduced repair rate of 5% after improvements. The project met the minimum requirements for a Lean Six Sigma Yellow Belt mini-project.

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Project Tittle:
Reduce Weld Repair Rate
from 15.5% to 5%
Yellow Belt Name:
Mutiara Dari Timur
Define M A I C
CONTOH
TEMPLATE
TUGAS
Business Field:
Engineering Company

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CRITICAL TO QUALITY
(Type of Weld Defects)
Define M A I C
Porosity
Slag Inclusion
Root Concavity
Lack of Fusion
Undercut

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Photo Defect
(Type of Weld Defects)
Define M A I C

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DIAGRAM SIPOC
Process Welding
DEFINE M A I C
Clean Weldment
SUPPLIER INPUT PROCESS OUTPUT CUSTOMER
Welding Store
Material Store
Fit-up Section
Inspection by QC
Welding Machine
Fit-Up Assembly
Welding
Consumables
Welding Procedure
Tacking Process
Welding Process
Welding Visual
Visual
Inspection
Delivery to
Customer
Good Product
Porosity
Slag Inslusion
Rood Concavity
Lack of Funsion
Undercut
Customer/User
Principal
Customer Inspector
OK
NG

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DEFECT PROPORTION TABLE
Sigma Level : 3.4
Week Output Defect Qty Proportion
I 173 33 0.1907
II 373 98 0.2627
III 396 81 0.2045
IV 405 89 0.2197
V 644 73 0.1133
VI 1075 158 0.1469
VII 423 27 0.0638
VIII 414 46 0.1111
Total 3903 605 0.1550
% 15.5%
Sigma Level 3.4
MEASURE
D A I C
Defect = 605
Sample Size = 3903
Opportunities = 5
DPMO = (Defects x 1.000.000)/(Sample Size x Defect Opportunities)
= (605 x 1.000.000)/(3903 x 5)
= 31.002

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Grafik Defect
MEASURE
D A I C
8
7
6
5
4
3
2
1
25
20
15
10
5
Minggu
Prosentase
defect
11.11
6.38
14.70
11.34
21.98
20.45
26.27
19.08
Time Series Plot dari Prosentase defect
Current Mean
percentage defects =
15,5%
Grafik Defect periode : Januari-Februari 2020

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DEFECT PARETO
The highest percentage
of defects = Slag
Inclusion (35.4%)
MEASURE
D A I C
Pareto Defect periode : Januari-Februari 2020

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CAUSE-EFFECT DIAGRAM
ANALYZE
M
D I C
Slag Inclusion
Man:
• Skill juru las
• Kurang Pelatihan
• Kurang Disiplin
• Kelelahan
Material:
• Kualitas bahan rendah
• Perlakuan bahan salah
Mesin:
• Kurang Perawatan
• Cara penggunaan
• Frekuensi penggunaan tinggi
Metode:
• Posisi Pengelasan
• Cara pengelasan
• Pengawasan kurang
• Prosedur
Lingkungan
• Pencahayaan rendah
• Kecepatan angin tinggi
• Layout Workshop tidak
maksimal
• Area kerja kotor
• Area kerja berantakan
Pengukuran (Measurement):
• Standard pengukuran tidak
seragam

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IMPROVEMENT PLAN
IMPROVE
M
D A C
No Plan When
Maret’20 April’20 Status
1 2 3 4 1 2 3 4
1 Melakukan Program Ringkas Plan
Done
Actual
2 Melakukan Program Rapih Plan
Done
Actual
3 Melakukan program Resik Plan
Done
Actual

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IMPLEMENTASI PROGRAM 5S
IMPROVE
M
D A C
BEFORE IMPLEMENTATION AFTER IMPLEMENTATION

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DEFECT PERCENTAGE AFTER
IMPROVEMENT
IMPROVE
M
D A C
Week Output Defect Qty Proportion Pecentage
I 898 44 0.0490 5%
II 1205 60 0.0498 5%
III 758 28 0.0369 4%
IV 987 48 0.0486 5%
3848 180 0.0468 5%
Current Mean percentage
defects (after
Improvement) = 5%
Grafik Defect Mei 2020
Rata rata defect = 5%
Defect = 180
Sample Size = 3848
Opportunities = 5
DPMO = ((180x 1.000.000)/(3848 x 5)
= 9.356

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IMPROVEMENT RESULT
IMPROVE
M
D A C
Before After
Defect (%) 15.5 5.0
DPMO 31.002 9.356
Sigma
Level
3.4 3.9

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NEW WELD PROCEDURE
CONTROL
M
D A i
• Procedure Clean weldment
• Procedure 5R

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Referensi:
Alfian Huda, Sri Widiyanesti. Analisis Pengendalian Kualitas Proses Pengelasan
(Welding) Dengan Pendekatan Six Sigma Pada Proyek Pt. Xyz: Jurnal Wacana
Ekonomi.
CONTROL
M
D A i
Catatan:
Jika menggunakan real case tidak perlu diisi

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LSS YELLOW BELT MINI PROJECT CONTENT
(Minimum requirement):
1. Grafik (time series)
2. Pareto
3. SIPOC
4. DPMO dan Sigma Level
5. Cause Effect Diagram
6. Improvement Plan/Activity
7. Result (Before-After)
8. Pareto, DPMO, Sigma Level (After)
9. Control-Procedure
Optional:
1. Scatter Diagram
2. Histogram

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