1) Frequent faults with the Properzi casting wheel flange such as broken or loose bolts, jerking wheels, and misaligned wheels were causing stoppages and downtime at the DUBAL aluminum plant. 2) An analysis found that weak bolts were the root cause, so additional and modified bolts were installed. 3) This solved the flange issues, eliminating downtime and increasing machine availability with zero faults since the improvement in 2010. Savings of 472k AED were projected from not buying a new flange.

1. Quality Month: November 2011 Kaizen No. Page No.:
KAIZEN REPORT
Dubai Aluminium Company Limited (DUBAL) Department: Casthouse Maintenance Section/Process: Properzi Ingot Casting
Improvement Title: Reduction of frequent faults related to Properzi Casting Wheel Flange
Category: [√] Quality improvement [ ] Health & Safety [ ] Environment [√] Productivity [ ] Office processes [ ] Product design improvement [ ] Service improvement
Before Situation Root Cause Analysis Improvement Measures After Situation
Before After
• Provided additional pins for the flanges
Average per Month
Worn-out Pin Fish bone diagram: Probable causes 2008 2009 2010
2011
and Hole Negative
Men Wrong Method YTD
attitude
Unskilled installation Original bolts: 20
Maintenance
Wrong
Nos. (22mm) No. of Work Order 2.7 0 0 0
New Procedure Wrong
Untrained
Operators Operation
operators
Worn out Metal Equipment Downtime
Wrong Data
Chamfer (where Poor Spillage Entry Additional 1.94 0 0 0
Maintenance (modified) 10 (Hrs)
the copper ring
seats) Pins (44mm)
Defective Pins / Weak Maintenance Man-hours 11.72 0 0 0
bolts Bolts
Wrong Pins
Misaligned Wrong Original bolts
Wrong selection wheels casting
(20 Nos.) Maintenance Cost (AED) 1.4K 0 0 0
Belts
Bolts are not of metal Wrong spares
in the centre
No standard
of the holes specification
Design Modified pins
Material Machine
• Frequent faults related to Properzi Casting
Wheel flange were due to: o 4th replacement on 27/01/2009 - Modified
Flange with old Copper Ring
o Broken or loose Casting Wheel Bolts
o Jerking of Casting Wheel o Produced drawing/ design in-house
o Unaligned Casting Wheel Conclusions and Root Cause (s): Bolts are in the
o Above faults will lead to Cast stoppage • Critical discussion on probable causes highlighted th
o 5 replacement on 20/07/2010 - Modified centre of the hole
• Even if it is one sheared bolt, the casting o Design related issues (Less number of Bolts) Flange from Properzi with new Copper
operations gets hampered • Further study on the shop floor validated “Weak Bolts” as the root Ring (Note: Still running without a single
• Sheared bolts also affect the Casting Wheel cause of frequent faults bolt broken)
Belt Life
Benefits: Participation
• Zero Faults related to Wheel Flange - Less downtime calls due to bolts broken and increased machine availability
 Roy Flores – General Superintendent, Casthouse Maintenance
• Eliminates metal spillage due to misaligned flanges – More safety work environment
 P. P. D’ Kutty – Supervisor, Mechanical Maintenance, Ingot & Foundry
• Increased reliability of the casting belts  D. Kumar – Mechanical Technician
• Projected savings of 472K (one-off) – in place of buying New Flange from OEM  C. Hugos – Mechanical Technician
Standardization Horizontal Deployment Opportunities (Replication):
 One off Machine (Properzi Casting) in DUBAL and hence not applicable to other machines
 Same modification was adapted by OEM, as the 5 th replacement of casting wheel flange that they supplied
was already modified as per DUBAL’s recommendations.
- Released related Drawing / Design
Single Point Lesson: Remark / Management Comments: An excellent in-house development that has increased average
running hours of the machine and no bolt failure.
Improvements on designs can still be carried-out in-house without relying much on OEMs.
Sign: Nasser Al Khaja, Senior Manager – Area Maintenance
Copy Distribution: Date of Starting: Date of Completion: Control No. (by DQG)
January 2009 July 2010
Declaration: We are submitting this Kaizen case voluntarily to DQG for participation in “Improvement Case Studies – KAIZEN” competition. We are glad to authorize DQG to share this information with the Business community at
large to promote Continual Improvement and good practices.
Signed by Authorised signatory: __________________________ Name: Nasser Al Khaja Designation: Senior Manager, Area Maintenance Date: 15/ 10/ 2011