Application of Six Sigma at cell site construction: a case study

Asian Journal on Quality Emerald Article: Application of Six Sigma at cell site construction: a case study Hakeem Ur Rehman, Muhammad Asif, Muhammad Aamir Saeed, Muhammad Asim Akbar, Muhammad Usman Awan Article information: To cite this document: Hakeem Ur Rehman, Muhammad Asif, Muhammad Aamir Saeed, Muhammad Asim Akbar, Muhammad Usman Awan, (2012),"Application of Six Sigma at cell site construction: a case study", Asian Journal on Quality, Vol. 13 Iss: 3 pp. 212 - 233 Permanent link to this document: http://dx.doi.org/10.1108/15982681211287775 Downloaded on: 27-11-2012 References: This document contains references to 18 other documents To copy this document: permissions@emeraldinsight.com Access to this document was granted through an Emerald subscription provided by Emerald Author Access For Authors: If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service. 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The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. *Related content and download information correct at time of download. The current issue and full text archive of this journal is available at www.emeraldinsight.com/1598-2688.htm AJQ 13,3 Application of Six Sigma at cell site construction: a case study 212 Hakeem Ur Rehman and Muhammad Asif Institute of Quality & Technology Management, University of the Punjab, Lahore, Pakistan Muhammad Aamir Saeed Management Sciences, COMSATS Institute of Information Technology, Wah Cantt, Pakistan, and Muhammad Asim Akbar and Muhammad Usman Awan Institute of Quality & Technology Management, University of the Punjab, Lahore, Pakistan Abstract Purpose – The aim of this case study-based paper is to study the application of Six Sigma, a breakthrough improvement strategy in the field of cell site construction of a telecom company. Design/methodology/approach – This research provides action research of a Six Sigma project using DMAIC methodology carried out in cell site construction function of a telecom company. The research illustrates how the various Six Sigma tools and techniques were applied in a mutually inclusive manner in one project. The infrastructure department of the company had constructed 900 cell sites last year, out of which 150 were not according to standards and were either disapproved by the operations department or underwent maintenance soon after their use. In 2010, the company spent US$ 0.5 million on rework and maintenance at these sites, thus highlighting the urgency of the problem. Findings – The paper shows how, after the implementation of the Six Sigma project, the company made savings worth US$ 0.45 million. Originality/value – Six Sigma as a means of waste reduction has gained popularity among researchers and practitioners. The literature on the methodology of Six Sigma and the management approach towards Six Sigma is burgeoning. While various Six Sigma tools and techniques and their application are discussed in literature independent of each other, the need has arisen to observe their systematic application as they apply in a project; every company can use this breakthrough improvement strategy to improve its processes by reducing waste and deriving the financial benefits. Keywords Construction operations, Six Sigma, Telecommunications industry, Cell sites construction, Waste reduction, DMAIC methodology Paper type Case study Asian Journal on Quality Vol. 13 No. 3, 2012 pp. 212-233 r Emerald Group Publishing Limited 1598-2688 DOI 10.1108/15982681211287775 1. Introduction Six Sigma has gained widespread popularity in industry as a process improvement methodology. It is defined as a “process of business operations which make it possible for companies to rigorously make better their basic formation” (Harry and Schroeder, 2000, p. vii). The concept of Six Sigma started from Motorola Inc, in the USA in about 1985, with the purpose of reducing the number of defects in a process. The name Six Sigma suggests a goal of reducing the number of defects to 3.4 defects per million opportunities (DPMO). Six Sigma uses a structured approach to reduce the number of defects to this level. Following successful implementation of Six Sigma by Motorola, a large number of companies have implemented it and success stories are discussed in the literature. Six Sigma had its origin in practice; however, literature on Six Sigma is burgeoning. Given the widespread acceptance of Six Sigma in industry it is argued that the academic community should continue research on this topic in order to better understand its underpinning principles, application, benefits, and critical success factors (CSF). The existing literature has discussed the definition and basic concepts, underlying principles, methodological issues, deployment process, and general management approach toward Six Sigma. While this type of research is essentially required for better understanding the theory of Six Sigma – such as definition, basic concepts, and critical factors – there is little action research describing the rich process of Six Sigma implementation – including Six Sigma methodology, process of implementation, and impact of Six Sigma implementation. This paper provides an elaborated account of Six Sigma implementation in a telecommunication company through an action research. The detailed implementation process of Six Sigma started from the development of a project charter through implementation process to results and then comparison with the preimplementation process. The paper should provide a thorough understanding of the dynamic process of Six Sigma implementation. The rest of the paper is structured as follows: the next section provides an overview of Six Sigma literature. This is followed by a detailed description of Six Sigma implementation process. Finally, conclusions are presented. 2. Literature review Six Sigma is defined as a data-driven approach to analyzing the root cause of business problems and solving them (Blakeslee, 1999). Hahn et al. (2000) described Six Sigma as a disciplined and statistically based approach for improving product and process quality. Motorola set the goal of 3.4 DPMO so that process variability is 76 SD from the mean. Under normal conditions a process can undergo deviation of 1.5 SD from the mean. This means that a three-sigma process would result in a 66,810 DPMO or 93.3 percent process yield. In a Six Sigma process, on the other hand, a deviation of 1.5 SD results in a 3.4 DPMO and 99.99966 percent process yield. The ultimate purpose is to reduce variation and to cut the costs. Consideration of monetary benefits is an essential component in Six Sigma projects. The Six Sigma methods commence only once the monetary benefits are established and this bottom line keeps the interest of management alive in Six Sigma projects (Brady and Allen, 2006). The literature on Six Sigma could broadly be classified into two categories. The first is the methodological literature that describes the structured approaches to Six Sigma implementation. Brady and Allen (2006) found that popular books and training material on Six Sigma focus mainly on statistical methods. In so doing, they omit much of the associated theory and include simplified version of standard statistical methods. The first type of literature provides an elaboration of the systematic approaches used in Six Sigma implementation. Brady and Allen further found that a large amount of literature focusses on the methodological aspects of Six Sigma. The second type of literature focusses the management approach to Six Sigma implementation. It highlights the factors that are critical to implementation, including role of leadership, teamwork, and social dynamics of implementation. The examples of the two types of issues discussed in the literature are summarized in Table I. The first type of literature focusses on the methodologies and frameworks for systematic Six Sigma implementation. Two approaches that are common in practice include define-measure-analyze-improve-control (DMAIC) that is used in process Six Sigma at cell site construction 213 AJQ 13,3 214 Table I. A categorization of Six Sigma literature improvement and define-measure-analyze-design-verify used in product/service design improvement (Linderman et al., 2003). Both of these approaches have their roots in the plan-do-check-act cycle of process improvement. The use of these improvement frameworks provides a structured approach to the execution of Six Sigma project. The structured approach also facilitates teamwork and promotes learning and knowledge acquisition within teams (Choo et al., 2007). To support the systematic implementation, Six Sigma also employs various quality management (QM) tools and techniques to find the root cause of the problem and for introducing process improvement (Linderman et al., 2003). These tools and techniques include use of Ishikawa diagram to find the root cause of the problem, Pareto analysis to prioritize problems, histograms to check the distribution of a process, and control charts to track the trends in a process. QM practices can be used in combination with Six Sigma to improve process performance (Zu et al., 2008). Table II provides some illustrative tools and techniques that could be used during various stages of Six Sigma project. A key step in any Six Sigma project is to determine exactly what customer requires and then defining defects or problems in terms of critical to quality (CTQ) parameters. Commonly used CTQ include process capability, defect measures, 10  improvement measures, cost, time: service time, waiting time, and cycle time, and information: Issues in Six Sigma methodology literature Issues in Six Sigma management literature Six Sigma methodology in manufacturing Six Sigma methodology in services Six Sigma methodology during product/service design Tools and techniques Critical to quality metrics Key performance indicators Role of teamwork Role of leadership Benefits from Six Sigma implementation Obstacles in Six Sigma implementation Theory of Six Sigma Discriminate validity of Six Sigma from TQM Critical success factors Illustrative process improvement tools and techniques Purpose of use Ishikawa/fishbone diagram Root cause analysis of a problem. Identifying all the possible causes of a problem and sorting the most relevant one Pareto analysis Prioritization of problems. Isolating the vital few from trivial many Scatter plot To check the distribution of data Histograms To check the distribution of data with respect to control limits and mean of the process Control charts To track trends in a process Process capability To check the health of a process – how the data is distributed with Table II. respect to control limits and mean An illustrative list of tools Failure mode and effect analysis To have better understanding of problem failures based on their and techniques used at severity, detectability, and occurrence various stages of process Design of experiment Decision making through selection from a number of choices improvement Check sheet Quantification of problems of various types accurate and timely information. In addition, key performance indicators (KPI) are also used to show data of a particular outcome. The outcomes of Six Sigma implementation are expressed in financial terms to make it easy to understand (Goh, 2002) and to promote greater buy-in by management. The commonly used KPIs include efficiency, cost reduction, time-to-deliver, quality of the service, customer satisfaction, employee satisfaction, reduced variation, and financial benefits (Chakrabarty and Tan, 2007). Use of quantitative measures provides a systematic approach to problem solving and also reduces corporate use of political agendas to drive solutions (Brewer, 2004). The second type of literature focusses on the management approach to Six Sigma deployment. One example of this type of literature is study of CSF, which are necessary for the successful implementation of any Six Sigma program. A number of CSFs are discussed in literature which significantly influence the implementation of Six Sigma. Based mainly on Chakrabarty and Tan (2007), Coronado and Antony (2002), and Goh (2002), Table III provides some illustrative examples of CSFs of Six Sigma. A number of issues that are discussed in this type of literature are discussed as follows. An essential component of Six Sigma methodology is the use of teamwork where people from various disciplines – such as production, maintenance, R&D, sales, marketing, and customer management – are invited for problem solving and process improvement. Linderman et al. (2003) found that explicit Six Sigma goals make the team efforts persistent and increase the direction of teams toward objectives. Top-management support is critical for the success of Six Sigma projects. This is because Six Sigma projects require allocation of resources and development of crossfunctional teams. Six Sigma uses a group of improvement specialists, typically referred to as champions, master black belts, black belts, and green belts depending upon their expertise and involvement in Six Sigma projects. Leaders initiate, support, and review projects; black belts serve as project leaders and mentor green belts in problem solving (Barney, 2002; Schroeder et al., 2008). Illustrative critical success factors Source Top management commitment Coronado and Antony (2002), Goh (2002), Henderson and Evans (2000) Brady and Allen (2006), Coronado and Antony (2002), Goh (2002), Kwak and Anbari (2006) Coronado and Antony (2002), Kwak and Anbari (2006) Brady and Allen (2006) Brady and Allen (2006), Coronado and Antony (2002), Goh (2002), Linderman et al. (2003), Schroeder et al. (2008) Linderman et al. (2003), Schroeder et al. (2008), Sehwail and DeYong (2003) Brady and Allen (2006), Linderman et al. (2003), Schroeder et al. (2008) Goh (2002), Henderson and Evans (2000) Education and training Cultural change Change management Customer focus Performance metrics Goal-based approach Linking the project success to financial benefits Organizational understanding of work processes Project selection Linderman et al. (2003), Schroeder et al. (2008) Brady and Allen (2006) Six Sigma at cell site construction 215 Table III. Illustrative examples of critical success factors of Six Sigma implementation AJQ 13,3 216 The implementation of Six Sigma requires action along both core practices (consisting of Six Sigma tools and techniques) and infrastructural changes to support core practices. Schroeder et al. (2008) discussed Six Sigma in terms of meso-structures. Meso-theory concerns the integration of micro- and macro-level of analysis. The examples of micro-level approaches employed in Six Sigma projects include statistical methods. At macro-level Six Sigma projects require overall assessment of Six Sigma and QM program and quantitative analysis of management practices. The meso-level is about optimal design of project strategies. Six Sigma projects are reported in literature as a combination of macro-level strategy and micro- and meso-level tactics. The meso-approach to Six Sigma is also discussed by other authors including Brady and Allen (2006) and Schroeder et al. (2008). The crux of the debate is that Six Sigma implementation requires micro- and meso-level tactics to achieve strategic objectives and such efforts need to be organized along both technical and social side of the organization. This research provides a case study of Six Sigma implementation at a telecom cell site construction company. The detailed process of Six Sigma implementation is discussed along with tools and techniques used for this purpose. 3. Research methodology This research is based on action research. Action research is a field experiment to solve real life problems. It involves both researcher and practitioners in the experiment. During action research the aim is discovering facts and altering certain unsatisfactory conditions experienced by the organization by changing the process of the system itself (Krishnaswamy et al., 2006). The action research starts with the identification of a problem area and then specific problem in organizational setting, recording of the actions taken and the accumulation of the evidence of the degree to which the goal has been achieved; and drawing inference regarding the relationship between the actions and the desired goals (Krishnaswamy et al., 2006). The telecom company experienced a number of problems with its cell site construction. The newly developed cell site constructions were not up to the requirements and were either rejected by the operations department or came under maintenance soon after their use leading to failures of different types and, thus, adding to costs. Management decided to address this issue through implementation of a Six Sigma project. A team was constituted for this purpose. The team consisted of a Six Sigma consultant, a project manager, four civil engineers, one electrical engineer, and one rigger. Researcher was a part of the team and was able to observe, analyze, and intervene the process, when needed. All the processes and activities in the Six Sigma project were documented. The action research approach provided in-depth insights into the research. Researcher was able to observe the process, make necessary interventions, and assess the outcomes of such interventions. Once the project was decided, team was constituted, and project charter was developed. The Six Sigma methodology employed for this purpose was DMAIC. To analyze and improve the process different tools and techniques were used. Minitab 15 was used for data analysis. During the whole process teamwork was a conspicuous element. For example root cause analysis to identify the possible causes of problem and to find the causes most relevant in this project benefited extensively from the teamwork. The DMAIC methodology used for this purpose is discussed as follows. Implementation of Six Sigma: DMAIC methodology 3.1 Define phase The define phase consists of three activities: to define the project charter; to do supplier, input, process, output, control (SIPOC) analysis; and mapping the existing process to see its current health. The project charter outlines the whole project. The project charter consists of: (1) defining the problem statement; (2) why the problem is worth addressing. This is also called defining business case – why the company should do that particular project; (3) discussing project goals; (4) defining measurement metrics to track the performance; and (5) defining the project scope. The project charter is shown in Table IV. Six Sigma at cell site construction 217 3.1.1 D1: project charter 3.1.2 D2: SIPOC diagram. The next step is SIPOC analysis which consists of identifying supplier, inputs, process, outputs, and customer of the whole process. The SIPOC analysis describes the whole process at macro-level. It tells how the process serves its customers; where the process originates; who are the suppliers; who are the customers; how the inputs are processed and transformed into final output; and what the intermediate steps are. The SIPOC analyses, thus, helps to better understand the whole process and makes improvement possible. SPOIC analysis start from cell planning department which will crisscross the area for construction of cell according to the number of users and signals; then, it will forward its reports to marketing department. Marketing department will prepare a feasibility report according to business opportunities and revenue. Keeping in view the reports of marketing and cell planning department, the project management department will plan visits and send its report to the acquisition department. This department acquires the land fulfilling the requirements of other departments. Business case Infrastructure department of the company constructed 900 cell sites last year out of which 150 sites were not as per standards, either these were not accepted by operation department due to quality issues or came in maintenance work after some time. The company has spent US$0.5 million on rework and maintenance at these sites last year. This project envisages the improvement in cell sites construction by 90 percent to save US$0.45 million or rework cost as hard savings Problem Overall expenditures have been raised due to rework. Moreover during rework/ statement maintenance operations of affected sites stops. This affects the quality of service and caused the company to lose its strategic advantage over other telecom companies Goals To eliminate the number of defects by 90 percent in site acceptance To improve the quality of cell site construction by applying quality checks at different phases To reduce/eliminate the cost of maintenance from US$0.5 million to US$0.05 million Metric Primary metric(s): number of sites rejected because of defects blocking installation of radio equipment, number of sites locked due to civil work (production) issues Secondary metric(s): selection of vendor, proper testing of material, targeted timeframe, new quality checks Project scope The project targets reduction of defects in new sites construction and improve quality to avoid maintenance Table IV. The charter of the Six Sigma project AJQ 13,3 218 After land acquisition, the design department will make design calculations according to soil data and a physical visit performed by all technical depts. Representatives check and report on the suitability of required site in terms of land, area, coverage requirement, arial clearance from any other nearby site to connect the new site through microwave link and finally a design is delivered to the infrastructure department. Infrastructure department, following the standard operating procedures (SOP) guidelines, announces a tender, and short lists the vendors. After analysis, the site is awarded to a selected vendor. Now the vendor starts the site construction process while developing a layout according to site marks the area. After this, according to design requirements, the site is prepared for “concrete” by arranging the stubs, make steel fixing, and template checking. Foundation structure would be completed after concreting the pads and tower foundation. When the basic structure is developed, the floor would be compacted and finalized after construction of the shelter and generator foundations. Then, according to the specification of towers and shelter drawings, tower erection and shelter installation and electrification with grounding works process is completed, as well as completion and testing of generators installation. Finally, the site would be completed after performing these activities which satisfy the drawing requirements; flooring and boundary wall would be constructed according to site requirements and final inspection would be made, keeping in view the SOP. The infrastructure department will make final inspection of site and will hand over to OAM or O&M (operations and maintenance) (Table V). 3.1.3 D3: process map. Process map shows how the new site comes about. It shows the different phases of construction of the cell site. Process of cell construction starts from the department of cell planning, after inspection of different sites and making some observation and suggestions, a request is forwarded to project management department. Project management department, after the recognition of request, visits that area with different departments such as TXN, production and acquisition, and cell planning. If all the departments are agreed on the proposed site, the land acquisition department will make an agreement with the owner. If all the departments are not agreed on the proposed site, another visit will be planned and after feedback a site will be selected or proposed. After this, the infrastructure department makes some soil tests and develops a design. Then, the site will be awarded to vendor who will nominate a site engineer to develop a layout and excavate the site. After stubs and steel fixing, foundation pad and columns will be concreted and tower erected. After backfilling the tower, shelter, genset pad is constructed and painted. When the sheltering and electrification process is completed, the genset is installed and checked. Boundary wall and floor will be constructed. After this a comprehensive inspection will be made and all the issues will be removed; and after some rework activities, if required, the site will be handed over to O&M (from this stage, O&M department will take care of this site and in case of any issue O&M department will do the rectification and maintenance of the site). At the end, data will be collected, equipment installed, and finally the new site will be completed (Figure 1). In measure phase; cause and effect diagram is used to describe the causes and subcauses of the main problem and after that the list of the defects provided in detail which researchers find from the sites. Current process performance measure using Six Sigma metrics which shows currently process is working at 4.8 sigma level, target set to reach at 5.0 sigma level. Third, in analysis phase; through graphical Supplier C/N Requirements Inputs Process Output Customer Cell planning department N Number of users, signals Site selection Selected site INFRA Marketing department Project management department Acquisition Designer INFRA Vendor N Revenue Drive test – drive around the area of required site using drive test tool to determine the available signal strength and recommendation of site type and configuration Business need C Request from CP/ commercial/MKT Plan visits N C C C Plot documents Soil data, JV SOP Site annexure Other departments requirements Soil report Design calculations Contractors list Site awarding to contactor Marking the areas for tower, shelter Site construction and generator Excavation and Lean Removing the loose earth according to tower design and pour 4 inch plain concrete to make the bed leveled and hard Stubs and steel fixing Stubs are the main legs of the tower which are fixed in ground and covered with reinforced concrete Stubs and template checking Template is fixed on the top of first main four legs of the tower to keep the equal distance to legs from each other and to keep the slopes of main legs equal Concreting of pads and columns for tower foundation Site design Site design INFRA Site awarded Vendor Marking INFRA Prepared for concrete Foundation structure (continued) Six Sigma at cell site construction 219 Table V. SIPOC diagram C/N Requirements Tower drawings Shelter drawings Drawings Drawings INFRA C Site Design SOP Final inspection Inputs Process Pouring the concrete of tower foundation including pads and columns Backfilling Filling of excavated area with sand and earth with compaction Construction of shelter and genset pads Preparing the foundations of shelter and generator Tower erection and painting Tower erection according to drawings, fixing the bolts, grounding of tower, and painting Shelter erection and electrification Fixing the shelter, installing A/Cs, distribution board, fire system, lighting and grounding Genset installation Installation of generator and connecting with the shelter Complete earthing Laying the complete grounding system and testing to make sure that the grounding value is o1 ohms Flooring and boundary wall constant Final inspection Site completion HO/TO form Output AJQ 13,3 220 Table V. Supplier Customer Compaction Pads completion Tower completion Shelter completion Genset testing Site completion Site handed OAN over to OAN Notes: INFRA, infrastructure department; CP, cell planning department; MKT, marketing department; PM, project management department; ACQ, acquisition department; JV, joint visit; C, controllable; N, noise Cell planning Cell site construction process Request for new site Observations and suggestions Drive test Issue DD 4 N PM Acknowledge request Escalation mail to other depts Joint visit conducted with TXN, Dep, Prod, Acq, CP for an option All dept. agreed Feed back from all depts Acquisition Prepare buildout OAN/Dep. Infrastructure Infrastructure Agreement with site’s owner Infrastructure Y Site location handing over to production Site clearance Soil investigation and design Awarding to contractor Layout, excavation and lean concrete Nominate site engineer Stubs and steel fixing 1 N Stubs and template checking/ rechecking 1 Ready for concrete Y Foundation pads and columns concreting Backfilling Shelter and genset pad construction Tower erection and painting N Genset installation and testing 2 Complete earthing Flooring and B/W construction Inspection Ready to HO to OAN Y Shelter erection and electrification 2 Checking for issues and rectification/ rework 3 N 3 Site handing over to OAN Accepted Y Data gathering Equipment installation New cell site born Site onair 4 Six Sigma at cell site construction 221 Figure 1. Process map – cell site construction AJQ 13,3 222 representations and severity of defects, the researchers found that most of the sites are having issues of shelter leakage; antenna mounts issue, settlement of flooring and more grounding value issue, so the impact of these defects causes of site rejection. Fourth, in improvement phase; with the help of design of experiment (DOE) three selected variables (i.e. causes: training/skills, SOPs, material) addressed, in this result improvement found in the process. Fifth, in control phase; control plan and run chart used for monitoring/controlling the process. The details of these phases are as follows. 3.2 Measure Measurement phase is discussed in the following steps: . M1 – cause and effect diagram. . M2 – description of defects. . M3 – sigma calculation. 3.2.1 M1: cause and effect diagram. The researchers initially conducted a brainstorming session for the identification of the site rejection/maintenance reason: as a result of this valuable session, ten major defects were found, due to which the site’s rejection/maintenance takes place; and there are multiple causes of these defects. For the clear identification of these multiple causes, the researchers constructed a cause and effect diagram (Figure 2). Following are the causes of the major defects: . unskilled labor; . non-recommended material; . fabrication faults; Cause and effect diagram - “cell site construction” Measurements Materials No process of tower testing in factory Man Low grade steel Unskilled labour Poor quality crush Less number of quality checks Under size bolts Low quality earthing material Measurement equipment not calibrated Weather condition Environment Fine sand Engineers not follow laws and procedures REJECTED SITES/ DEFECT RATE Less RPM of concrete mixing machine an d es s gl d r an da of tan t th r s no ba pe es nc s gl Zi a t n no of a g t in no an s le er C op gle pr an in g in ol er H rop p Rainy sand Figure 2. Cause and effect diagram – cell site construction Im pa prop ne er ls fix shelt ing er Labour not commited Poor shelter installation Compactor not working properly Silcon gun's adjustment issue Poor tower fabrication Methods Machines . installation faults; and . improper use of equipment. Six Sigma at cell site construction Due to these causes we face a lot of major and minor defects which result in the site’s rejection and rework. 3.2.2 M2: description of defects. Ten major defects, due to which researchers find site rejection, are: (1) settlement of site flooring; (2) tower (main legs) foundation strengthening issue; (3) fire alarm not reporting/working; (4) tower galvanizing is o90 microns; (5) poor tower tightening; (6) oil leakage observed from genset and fuel tank; (7) grounding value is more than four ohms; (8) antenna mounts are not straight; (9) water leakage observed in shelter; and (10) A/Cs not cooling/working properly. There are some minor defects which result from these major defects (see Table VI). 3.2.3 M3: sigma calculation. For calculating sigma level, deep study of sites’ database was required. First of all, data collected from all stake holders and compiled it on a sheet. This one sheet has data of 900 nationwide constructed sites in the year 2008. From this data a sample of 200 sites was taken, this sample represents the total population. The data show the number of defects in each site (see Table VII). With the help of following data current sigma level is calculated. Opportunities for one site are 2,731; whereas total opportunities for 200 sites will be 2,731  200 ¼ 546,200. Total defects in 200 sites Total opportunities DPU (defects/unit) DPO (defects/opportunity) Yield DPMO Sigma ¼ 249 ¼ 2,731  200 ¼ 249/200 ¼ 1.245 ¼ 249/(2,731  200) ¼ 0.0005 ¼ 1DPO ¼ 10.0005 ¼ 0.9995 ¼ (249  106)/(2,731  200) ¼ 456 (defects/million opportunity) ¼ NORMSINV(0.9995) þ 1.5 ¼ 4.8 Our current sigma is 4.8 and our first target is to achieve 5 sigma. The next stage is analysis of the data. 3.3 Analysis Analysis phase is discussed in the following steps: . A1 – graphical representations. . A2 – severity of defects. 223 AJQ 13,3 Major categories of defects 1. Settlement of site flooring 224 2. Tower foundation strengthening issue 3. Fire alarm not reporting/working 4. Tower galvanizing is o90 microns 5. Poor tower tightening 6. Oil leakage 7. Grounding value more than 4 ohms 8. Antenna mounts not straight 9. Water leakage in shelter 10. A/Cs not cooling Table VI. Categories of issues Major defects Table VII. Defects and opportunities per site Settlement of site flooring Tower foundation strengthening issue Fire alarm not reporting/working Tower (main legs) galvanizing is o90 microns Poor tower tightening Oil leakage observed from genset and fuel tank Grounding value is more than 4 ohms Antenna mounts are not straight Water leakage observed in shelter A/Cs not cooling/working properly Total Sub defects 1.1 Poor backfilling material 1.2 Compaction not done in layers 1.3 Compactor not used 1.4 Improper cement sand ratio 2.1 Fine sand 2.2 Old cement 2.3 Poor mixing of concrete 2.4 Poor workmen ship 2.5 Less curing time of concrete 3.1 Wrong connections 3.2 Less battery life 4.1 Rusty angle 4.2 Zinc not as per standards 4.3 Low temperature during zinc bath 5.1 Undersize bolts 5.2 Improper fabrication of angles 5.2 Improper fixing of angles 6.1 Poor connection and sealing of pipes 6.2 Low-grade material 7.1 Non-recommended grounding cable 7.2 Less depth of grounding pits 7.3 Water inlet chocked in grounding pit 7.4 Improper/loose connection of cables 8.1 Poor fabrication 8.2 Slope level not checked 8.3 Poor fixation of mounts 9.1 Shelter panels fixing improper 9.2 Silicon not used properly 9.3 Silicon gun not working properly 9.4 Panel locks not adjusted 9.5 Roof drain not installed properly 10.1 Wrong connection 10.2 Gas leakage from outdoor units 10.3 Filters not cleaned 10.4 A/C timer faulty No. of defects/site causing major defect Opportunities/site 4 5 2 3 3 2 4 3 5 4 35 6 5 2 60 2,560 2 4 9 75 8 2,731 Issues vs no. of sites 40 35 30 25 20 15 10 5 0 No. of sites 32 225 27 24 19 18 G e su ge is C el te A/ rl nt s ea is ka su su is ou Sh nn An ro te un di a ng m O tig To w er e e e ue ak va l le il in en ht ni lva ga ag su is g ng zi ar al re Fi To w er st n io Figure 3. Issues vs number of sites Fo u nd at e e is is m is g in en ht ng re su su e su in or lo ff to en e 3 em ttl Se Six Sigma at cell site construction 38 35 31 22 g No. of sites 3.3.1 A1: graphical representations. Figure 3 shows the number of sites having different issues. This figure shows that most of the sites are having issues of shelter leakage; antenna mounts issue, settlement of flooring, and more grounding value issue. The next chart (Figure 5) shows percentage of issues in sites (Figure 4). Figure 5 is quite interesting in that it shows that in each month how many sites are without issues and how many sites are having issues. Next graph (Figure 6) is continuation of Figure 5, as it shows the number of sites with issue and also number of issues in these sites. Issues Issues rate Settlement of flooring 11% Foundation strenghtening issue 1% 13% Fire alarm issue 9% 15% Tower galvanizing issue Tower tightening issue 7% Oil leakage 14% 8% Grounding value issue 10% 12% Figure 4. Issues rate Antenna mounts issue Shelter leakage 35 Sites with issues Sites w/o issues 25 4 2 20 9 4 3 21 10 10 6 15 4 5 2 23 16 16 5 15 21 18 20 3 2 11 11 16 12 8 ec ,0 D N ov ,0 8 8 O ct ,0 8 8 p, 0 Se 8 Month Au g, 0 ,0 Ju l 8 Ju n, 0 M ay ,0 8 8 r, 0 Ap M ar ,0 8 8 Fe b, 0 ,0 8 0 Ja n No. of sites 30 Figure 5. Sites with issues in each month AJQ 13,3 45 40 Sites with issues 35 No of issues 30 226 39 38 28 25 24 23 20 17 14 11 10 5 4 2 0 9 4 3 10 10 6 5 10 4 2 3 2 Ja n, 08 Fe b, 08 M ar ,0 8 Ap r, 08 M ay ,0 8 Ju n, 08 Ju l, 08 Au g, 08 Se p, 08 O ct ,0 8 N ov ,0 8 D ec ,0 8 Figure 6. Time wise distribution of defects 18 17 15 Month The above mentioned graphs and charts show the number of defected sites and number of issues in these sites. Now the point is, which issues should be controlled in first phase so that sigma level can be improved. To know this, severity of defects needs to be known, which can be determined from Table VIII. 3.3.2 A2: severity of defects. Table VIII shows the defects and impact of these defects which are the causes of site rejection. By multiplying the occurrence rate with impact, the score can be calculated; this shows which issue is more critical to address first. The result of this table shows that first of all “high value” issues should be addressed to improve the quality of work in sites’ construction. 3.4 Improve The improve phase is detailed in the following steps: I1 – DOE. I2 – steps for improvement. I3 – results in improve phase. 3.4.1 I1: DOE. Researchers selected three variables (i.e. causes: training/skills, SOPs, material) from the cause and effect diagram, which researchers found needed Defect/issues Table VIII. Severity of defects Settlement of flooring Foundation strengthening issue Fire alarm issue Tower galvanizing issue Tower tightening issue Oil leakage Grounding value issue Antenna mounts issue Shelter leakage A/C issues Occurrence 32 3 22 18 19 24 31 35 38 27 1 Impact 2 3 4 5 Score Remarks 128 15 44 18 57 96 62 140 190 81 High Severe Medium Low Medium High Medium High High High attention after brainstorming session and which are the major critical factors for process improvement. At this point in the DOE analysis, the selected three variables are used to build a statistical table comparing the combination of low and high levels for each variable. Eight runs are created in the screening design, as shown in Table IX: (1) Training/skill level of technical staff: 1 shows low training/skill level of technical staff whereas 1 shows high training/skill level of technical staff. If staff is not trained/skilled, company facing more issues as compared to trained staff. (2) SOPs: 1 shows that existing SOPs are not being followed and SOPs and not updated; whereas 1 shows that existing SOPs are being followed. In case of unavailability of updated SOPs, or poor follow up of existing SOPs, issues will be increased as compared to proper implementation of SOPs. (3) Use of approved construction material: 1 shows that approved and recommended materials are not being used during construction; whereas 1 shows that approved and recommended materials are being used. In case of using poor quality/non-recommended material, issues will increase as compared to the use of approved and recommended construction material. Six Sigma at cell site construction 227 Following are the results of the experiment (see Figures 7-9). The result demonstrates that the three variables (material, SOPs, and skill level of staff) are playing major part in sites rejection. From Figure 10 it can be seen that poor or low-grade material is a big problem for us. Most of the defects are the result of using non-recommended/ approved materials. The second major cause of defects is unavailability of updated SOPs or non-implementation of existing SOPs. The third major factor is skill level of technical staff. These three major causes will be addressed to reduce the number of defects. 3.4.2 I2: steps for improvement. DOE shows the weak areas, and to overcome such areas, proper training of staff, revision in SOPs, and testing of material is required. To overcome this, the following steps are taken: (1) Material list: a new approved material list has been floated to all contractors and they can only proceed if approved material will be available at site. Testing of all materials will be done through a recognized body. Moreover, Training/skills SOPs (procedure) Material Result/defects per site 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 8 7 6 5 4 3 2 1 Table IX. Design of experiment (1 is low/poor; 1 is high/good) AJQ 13,3 Cube plot (data means) for defects/site 2 1 5 6 1 SOPs 228 3 4 8 –1 1 –1 Skill level er 7 at –1 M Figure 7. Cube plot for defects/site ia ls 1 Interaction plot (data means) for defects/site –1 1 –1 1 Skill level 6 4 2 Skill level –1 1 –1 1 6 SOPs SOPs 4 Figure 8. Interaction plot for defects/site 2 Materials all vendors will submit the following reports at different stages of site construction: . steel testing report; . concrete testing report; . compaction test report; . silicon test (water proofing of shelter); . level checking of antenna mounts; . . load checking of A/C; pressure test of fuel lines of genset and fuel tank; Six Sigma at cell site construction Main effects plot (data means) for defects/site Skill level SOPs 6 Mean of defects/site 5 4 3 229 2 1 –1 1 –1 Materials 6 5 4 3 2 Figure 9. Main effect plot for defects/site –1 0.000 1 Pareto chart of the effects (response is defects/site, α = 0.05) C B Team A AB AC Factor Name ABC A B C BC 0 1 2 3 Skill level SOPs Materials 4 Effect . . (2) Updated SOPs: revision in SOPs has been done. As per new SOPs mentioned, new forms are introduced: . . . (3) galvanizing test from Alco-meter of tower; and fire alarm testing by simulation. material checklist; site forms (tower, concrete, steel, quality check); and quality assurance form. Training of technical staff: a training plan is floated for engineers and site staff. Contractors will be responsible for the training of their staff and they will submit the reports on monthly basis. At least 40 hours training will be required in six months. Figure 10. Pareto chart of effects AJQ 13,3 230 3.4.3 I3: results in improves phase. After implementing of approved material, new procedures and training of staff, sigma was calculated once again. It is observed that ten sites in each month to check defects/site and again took sample of 80 sites for year 2009 (from January to August). Total issues observed are 48. Total defects in 80 sites Total opportunities DPU (defects/unit) DPO (defects/opportunity) Yield DPMO Sigma ¼ 48 ¼ 2,731  80 ¼ 48/80 ¼ 0.60 ¼ 48/(2,731  80) ¼ 0.00022 ¼ 1DPO ¼ 10.00022 ¼ 0.99978 ¼ (48  106)/(2,731  80) ¼ 219.69 (defects/million opportunity) ¼ NORMSINV (0.99978) þ 1.5 ¼ 5.02 Hence target has been achieved. 3.5 Control After analyzing and improving it is mandatory to control the process to maintain the results and to further improve the process. Control phase is detailed in the following steps: C1 – run chart. C2 – control plan. 3.5.1 C1: run chart. After taking the sample again from sites constructed from January 2009 to August 2009 it is observed that number of defects/site have been reduced and site’s rejection rate has been decreased as well. All the p-values indicate that there are no special causes. Figure 11 represents the results. 3.5.2 C2: control plan. After improving the process of cell sites’ construction, control plans for improved construction of cell sites established and implemented. After applying new check, process diagram is as shown in Figure 12. Run chart of defects/site Defects/site 4 3 2 1 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Observation Figure 11. Run chart of defects/site Number of runs about median: 11 9.33333 Expected number of runs: 7 Longest run about median: Approx p-value for clustering: 0.87454 Approx p-value for mixtures: 0.12546 Number of runs up or down: 19 Expected number of runs: 19.66667 Longest run up or down: 3 Approx p-value for trends: 0.38292 Approx p-value for oscillation: 0.61708 30 Cell planning New process - cell site construction Observations and suggestions Drive test Request for new site Issue DD 4 PM N Escalation mail to other depts Acquisition Acknowledge request Agreement with site’s owner Y 1 N Infrastructure Infrastructure Infrastructure All dept. agreed Feed back from all depts Site location handing over to production Site clearance Prepare buildout Soil investigation and design Awarding to contractor and nominate site engineer Layout and excavation Material checklist (by site engineer) N OAN/Dep. Joint visit conducted with TXN, Dep, Prod, Acq, CP for an option 1 Stubs and template checking / rechecking 2 Shelter erection and electrification All material ok Y Lean concrete of foundation pad N Ready for concrete Y Foundation pads and columns concreting Backfilling & compaction test Compaction test ok Y Shelter and genset pad construction Tower and antenna mounts checking in factory Stubs and steel fixing Tower erection and painting 2 Rectification of issues/rework 3 N Water proofing test on shelter Genset installation and testing Complete earthing Flooring and B/W construction Inspection of complete site Ready to HO to OAN Y N 3 Site handing over to OAN Y Data gathering Accepted Equipment installation Site onair New cell site born 4 Six Sigma at cell site construction 231 Figure 12. New process map – cell site construction AJQ 13,3 232 4. Conclusion Six Sigma has been used successfully in manufacturing industry for three decades. The real challenge was to employ Six Sigma in the telecom industry for construction of its sites. In this paper, it is concluded that Six Sigma is applicable in telecom (cell) sites construction. There are a lot of differences between constructions and manufacturing processes but with proper attention, Six Sigma works very well in cell sites’ construction. It may bring great benefits to telecom companies, especially when there is a big competition and number portability has been introduced. Any telecom company can only retain its customers if service quality is better than others, otherwise users will switch to another telecom operator. And for better service, cell sites construction quality is a major area where improvement is needed and this can be achieved if Six Sigma tools are used for construction’s process improvement. 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(2012), “Examining the implementation of Six Sigma training and its relationships with job satisfaction and employee morale”, Asian Journal of Quality, Vol. 13 No. 1, pp. 100-10. Corresponding author Muhammad Usman Awan can be contacted at: usman.iqtm@pu.edu.pk To purchase reprints of this article please e-mail: reprints@emeraldinsight.com Or visit our web site for further details: www.emeraldinsight.com/reprints Six Sigma at cell site construction 233