CASE STUDY OF A LEAN/ SIX SIGMA QUALITY PROJECT
Executing Lean Six Sigma: A Case Study on Manufacturing of Concrete Panel
Master of Science in Administration: Engineering Management
IET 670 Lean Manufacturing & Six Sigma Quality
Central Michigan University
Dr. Richard L Hayes
Lean Six Sigma technique is perceived generally and has been actualized predominately in production, when compared to the construction business. To outline the point, this paper attracts thoughtfulness regarding the selection of Lean Six Sigma in the construction business with a contextual analysis. The blend of Lean devices and Six Sigma technique is utilized in activities to enhance the procedure by disinclining the varieties, making work process in a procedure. Regardless of moderately new prologue to the development business, has been advanced by a few associations, also received as the essential change process.
Speculation of this study was that the Six Sigma procedure can be connected to the development based generation framework alongside lean development systems. To test this, we connected Lean Six Sigma techniques on concrete- panel production system in a multi-housing complex venture. The paper indicates how the production rate of concrete panel was enhanced and balanced out alongside the utilization of Lean Six Sigma apparatuses. Likewise, the contextual investigation utilizes the variety of panel production as a critical total quality (CTQ) to measure the execution marker of Six Sigma framework.
Numerous construction ventures experience the ill effects of fluctuation coming from single or different causes. A related guideline with waste expulsion is inconstancy diminishment (Bertselen and Koskela 2002). In the development business, origins of changeability incorporate late conveyance of material & gear, outline blunders, change orders, hardware breakdowns, apparatus glitches, uncalled for group use, work strikes, ecological impacts, inadequately planned generation framework, mishaps, and physical requests of work (Abdelhamid and Everett 2002).
Koskela (1992) called attention to that planners, architects, development specialists have for a very long time concentrated on change exercises and neglected issues of stream. In this way, this is critical to make stream by wiping out waste. Stream is critical for the fact that, work or materials that don\'t stream sit out of gear in stock, tying up cash and space (Tommelein and Weissenberger 1999). Then again, Six Sigma is a measurable based venture driven way to deal with enhance the association\'s items and generation framework to accomplish close flawlessness or \'nearest to zero-abandon\' item by concentrating on imperfection rates; at the end of the day, disposing of varieties in a procedure. Combination of Lean devices and Six Sigma approach is utilized on undertakings to enhance the procedure by taking out the varieties as well as making work process in a procedure.
In 1985, Bill Smith of Motorola created and actualized a way to deal with accomplish close flawlessness in item producing called Six Sigma (Breyfogle, Cupello and Meadows 2001). The attention on deformity rates and the express acknowledgment of the connection among the quantity of item imperfection, high working expenses, also the level of consumer loyalty makes Six Sigma interesting among different process change activities (Abdelhamid 2003). In the context of the Six Sigma approach, ‘sigma’ has been used as a metric that reflects the ability of a company to manufacture a product or provide a service within prescribed specification limits (or within zero defects) (Abdelhamid 2003).
There are two approaches used to accomplish Six Sigma objectives; Define, Measure, Analyze, Improve and Control (DMAIC). DMAIC, a five-stage shut circle critical thinking design that wipes out inadequate developments, also applies innovation for constant change.
• Defining and understanding the basic prerequisites, key variables & requirements of the customer which influences the procedure yield.
• Measuring the procedure and significant information to the procedure necessary through Six Sigma measurements.
• Analyzing the reasons for irregularities and sources of variety utilizing measurable quality control devices.
• Improving the procedure by determining in the examination stage the most basic source of variety.
• Controlling and observing the procedure varieties utilizing a measurable procedure technique to maintain the growths & improvements.
Deming and numerous others characterized two sorts of variety: normal cause & exceptional cause variety. In Figure 1, Xn speaks to the contributions to the procedure and Y is the yield. While the varieties in the sources of data (normal or unique causes), the subsequent Y will likewise be variable (Abdelhamid 2003). Six Sigma is an information driven critical thinking approach, where inputs (Xn) are distinguished and restructured to affect the yield (Y). The principal condition that drives Six Sigma is:
Y: output i.e., important aspects of business
f: Function i.e., how to manage interrelationships
X: Variables controlled to consistently predict Y
In 2002, Bechtel Corporation, one of the biggest building, construction organizations on the planet, announced reserve funds of $200 million with a speculation of $30 million in Six Sigma program to recognize & avert revamp and surrenders from configuration to development (Kwak et al. 2004). Advance cases of Six Sigma execution in designing are connected on a national media transmission venture to help advance the administration of cost & plan, and on a synthetic venture to streamline the way toward killing substance specialists (Moreton 2003).
Cp (process capability index) = (USL – LSL) / (6 x STDEV)
USL = upper specification
LSL = lower specification
STDEV = standard deviation of the data
Previous Six Sigma application to construction processes showed that the value of Cp was less than 1.0 (Han et al 2008).
The organization is building up the Phase II of the Jubail Industrial City in Saudi Arabia. Some portion of the Jubail Phase II improvement is to give 405 villas to the group. As of the speed, productivity underway and establishment, was chosen to develop the villas utilizing precast divider & floor panels.
Figure 1: Erection of villas
In any case, one year after issuance of Notice to Proceed (NTP) to the contractor, the contractual worker was 25% behind the timetable. With a specific end goal to maintain a strategic distance from the high danger of extra delays and deficiency of housing, a Lean Six Sigma study was attempted by Bechtel\'s Six Sigma Black Belt group. The point of the review was to comprehend and take care of the issue by accomplishing taking after objectives; 1) Improve efficiency of manufacturing, conveying pre-thrown protected panels to development site, 2) Establish reasons for deferral, address wasteful aspects at the pre-cast plant as well as propose improvement measures, 3) Achieve every single basic turning point per contract terms and conditions.
Figure 2: Pre-cast plant
LEAN SIX SIGMA PROCESS:
A Lean Six Sigma ponder begins with an issue articulation took after by characterizing the essential metric, which helps to concentrate on the issue territory and measures the yield or coming about Y. The essential metric for this contextual analysis was the \'Quantity of Exterior Insulated Panels Delivered to Construction Site every Day\'. Present state standard generation rate was 18 panels/day, and to retrieve the agenda, 75 panels/day was focused on.
To outline regular cause and extraordinary cause variety in an ordinary Six Sigma, the basic X\'s which are the contribution to the procedure are spoken to in Figure 4. Figure 4 distinctly shows how Lean tools were incorporated with Six Sigma system by distinguishing the basic X\'s in this procedure. The Value Stream Mapping (VSM) is the initial step to decide the potential X\'s. This might be noticed that the yield or coming about Y may likewise be variable, because of varieties in the sources of info. For this situation, the prime Y is the day by day generation rate of the pre-cast panels.
Figure 3: Lean operation matrix
The following are cases of steps made to view over some Critical X to enhance the profitability:
X1: Improve Leadership/Supervision
• Deploy loyal plant administrator
• Appoint general director
• Appoint four foreman, each devoted to 6 generation
• Hire full time Project Quality Engineer
X2: Optimize stream by expanding Resource Utilization
• Dedicate two (2) Gantry Cranes for generation range
• Add one (1) solid pail to permit synchronous work on numerous tables
• Start utilization of Ready-blend Trucks for dim solid conveyance
X3: Eliminate Waste through enhanced Inventory Management
• Reconfigure stockyard for better get to and control
• Reduce Inventory Level to a limit of 250
• Use Visual Controls to show item status (red-curing day 1, yellow curing day 2, green prepared for blasting)
• Status stock and create Electronic Inventory Logs to track stockpiling & conveyances
X6: Document Standard Work and Improve Logistics
• Prepare a rundown of standard exercises with clear parts, duties and accountabilities
• Measure process durations and diminish lead time by dispensing with waste
• Streamline conveyances by stacking trucks with boards for one part
By distinguishing the issues on the VSM (Figure 4), and handling over the basic X\'s, the manufacturing rate of 75 panels/day was accomplished (Figure 5).
Figure 4: Value stream map
Figure 5: Performance enhancement
Besides, Figure 5 demonstrates the measurable control graph which is utilized to detach basic from uncommon cause variety. The outline in Figure 5 indicates theoretical measurement figures, which is for this situation the \'No. of Panels Delivered every day\', for the result of Y plotted against time for month of July. Upper and Lower Control Limits (UCL and LCL) indicated are a component of the procedure mean, prepare extend, the standard deviation of the deliberate information (Montgomery 2001; Abdelhamid 2003; Breyfogle 2003). The diagram obviously shows that the procedure is under measurable control. In Six Sigma, a procedure is considered under measurable control if every one of the information focuses fall inside the LCL and UCL. The Cp (prepare ability file) is ascertained utilizing the condition (1) as takes after:
Cp (prepare capacity list) = (USL – LSL)/ (6 x STDEV) = (143.2-42.3)/(6 x 18.76) = 0.90 (2)
The estimation of Cp is 0.9, which is under 1.5, a suggested level for another generation in assembling based condition.
Figure 6: Sustained performance control chart
Perception working on this issue considers has uncovered that Lean instruments were utilized to recognize and to enhance some basic X\'s in a procedure. The basic X might be identified with specialized issues (such glitch of crane or solid pump, and so forth.), which then neither Lean nor Six Sigma would apply to fathom and enhance the basic X. Nonetheless, the reasonable for say, that Lean is best to use to address generation (or material science) issues (Ballard 2000) where stream in the process is not ideal, while Six Sigma is to recognize the deformities. The appropriation of Six Sigma generation instruments to enhance the association\'s items and creation framework were not adequate, as this neglect to accomplish a dependable work process.
This contextual analysis makes utilization of both Lean & Six Sigma instruments together to tackle development issues and is viewed as neither of the strategies in segregation would have been completely fruitful. In any case, the blend has a multiplier impact of the capacity to achieve an effective result. Substantial associations are ready to embrace the Lean Six Sigma system to enhance and take care of business issues on every day exercises.
Some of the conclusions drawn from the literature review and the case, can be summarized;
• Both Six Sigma & Lean are solid creation administration instruments and the blend supplements each other. Lean on a basic level disposes aspects that doesn\'t increase the value of the client and accomplishes solid work process. Then again Six Sigma plans to control and decrease the varieties by understanding the main driver. As examined in this paper, and additionally in Abdelhamid (2003), the blend of both instruments can prompt an extremely valuable philosophy to enhance any procedure.
• The multifaceted nature of the development extend has a remarkable and unverifiable conditions, which made the utilization of Lean Six Sigma philosophy some way or another unique in relation to alternate enterprises, particularly fabricating. Notwithstanding, as observed considering contemplate, real Lean Six Sigma devices have been effectively connected to enhance the procedure.
• The strategy of Lean Six sigma was powerful in lessening inconstancy of day by day board generation rate. In any case, considering acquired vulnerability in development forms, the estimation of Cp can be connected adaptably to development forms.
Construction organizations adopting Six Sigma may perceive that Six Sigma by is not adequate to handle issues, as needed to accomplish a dependable work process. Lean Six Sigma advances ceaseless change of procedures by variety and removing waste. Consequently, keeping in mind the end goal to be aggressive & imaginative, construction organizations need to apply both tools to handle their business issues.
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