International Journal of Science and Research (IJSR), India Online ISSN: 2319-7064 
                Application of Just In Time (JIT) Manufacturing 
                      Concept in Aluminium Foundry Industry in 
                                                          Zimbabwe 
                                                                       
                                    Ignatio Madanhire¹, Lovemore Kagande², Chancellor Chidziva³ 
                                                                       
                                           ¹University of Zimbabwe, Department of Mechanical Engineering 
                                                P O Box MP169, Mount Pleasant, Harare, Zimbabwe 
                                                           imadanhire@eng.uz.ac.zw 
                                                                       
                                           ²University of Zimbabwe, Department of Mechanical Engineering 
                                                P O Box MP 167, Mount Pleasant, Harare, Zimbabwe 
                                                            lkagande@eng.uz,ac.zw 
                                                                       
                                                         ³Craster International (Pvt) Ltd 
                                          Corner Gleneagles / Tilbury Road, Willowvale, Harare, Zimbabwe 
                                                           cchidziva@crasterint.com 
              
            Abstract: This research study investigates the use of Just in time (JIT) concept for the aluminium foundry industry. It explores the 
            adaptation of the manufacturing approach to metal foundry, where raw materials are imported in a highly unstable economy. JIT is 
            applied to improve cost effectiveness of operations, quality and to achieve world class benchmarks on all facets of the engineering entity 
            as competitiveness in product delivery is getting to be mandatory for business survival. 
              
            Keywords: just in time, foundry, aluminium, cost, effectiveness, world class 
             
            1.  Introduction                                               producing to stock to more modern systems such as Just 
            Global manufacturing and trading industry continues to         in time which are better suited to the current prevailing 
            evolve and, most businesses are now faced with an ever         competitive conditions in the market [4]. 
            increasing need to rapidly adapt to these changes.  The         
            changes include changes in market demand, product              Upgrading of manufacturing system to quickly respond to 
            designs, product life cycles, changes in production and        rapid market demand changes and other issues such as the 
            manufacturing technologies [1].  As markets gradually          scarcity of financial resources and material resources is 
            shift from mass markets into niche markets, it is              required. High breakdown frequency, non reliability in 
            becoming imperative that manufacturing entities respond        terms of products with consistent quality and reduced 
            with proactive strategies to ensure not only their             productivity militate against the supposed system 
            continued survival but also facilitate for their own growth    efficiency [5].  Hence Just in Time as a management 
            in a very competitive environment.                             philosophy it advocates for a holistic approach to 
                                                                           manufacturing whereby each activity in the production 
            Any organization needs to focus on quality of products,        system is analyzed and improvements made that will 
            the cost of products, timely delivery of products and the      ensure that efficiency is achieved in the manufacturing 
            flexibility of their internal business process to adapt to     system. 
            rapid changes [3].  The aspect of flexibility becomes very      
            critical especially when an organization is trying to          The benefits that are associated with the implementation 
            capture an immediate intermittent demand of a product.         of a JIT system include the following [7]: 
                                                                            
                                                                            
            2.  Justification                                                 better quality products 
                                                                              quality the responsibility of every worker, not just 
            The country faces a declining manufacturing production             quality control inspectors 
            capacity due to a number of constraints.  Companies are           reduced scrap and rework 
            industry grappling with obsolete equipment, skills flight         reduced cycle times 
            and depressed market activity.  Most raw materials                lower setup times 
            procurement involves importing.  Major challenges                 smoother production flow 
            remain the ability to supply products at the right time, in       less inventory, of raw materials, work-in-progress and 
            the right quantities, at the right level of quality and at a       finished goods 
            competitive price.                                                cost savings 
                                                                              higher productivity 
            Aluminium Foundry Co is facing stiff competition on the           higher worker participation 
            market from Asian suppliers.  One of the major obstacles          more skilled workforce, able and willing to switch 
            to their ability to compete is the lack of transition from         roles 
            the traditional systems of manufacturing such as 
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                       International Journal of Science and Research (IJSR), India Online ISSN: 2319-7064 
                 reduced space requirements                                           direction and, in the backward direction, the flow from 
                 improved relationships with suppliers                                suppliers. 
                                                                                        
              3.  Just in time concept                                                 3.1 JIT development 
                                                                                        
              JIT has been defined in a number of ways but the                         The present idea of JIT manufacturing can be traced to the 
              essential elements of JIT have remained the same. As a                   Toyota motor company in Japan.  However the concept 
              definition JIT is a manufacturing philosophy that aims to                was only adopted implemented and publicised by Toyota 
              eliminate waste, as waste is or results from any activity                of Japan as part of its Toyota Production System (TPS).  
              that adds cost to the production process without                         JIT was used by Toyota to deal with a problem of 
              necessarily adding value to the product, such as                         increasing and wasteful overstocking of cars they were 
              transporting inventories from one warehouse to the other                 producing around 1954[3]. 
              or the simple act of storing them. Waste in the following                 
              areas or from the following identified sources need to be                Basically, it is manufacturing set up whereby the usage of 
              reduced or eliminated [8]:                                               parts determined the consumption rates of the parts.  
                                                                                       Materials were “pulled” through the plant by usage or 
               
                Overproduction - waste from producing more than is                    consumption of parts in the final assembly.  To obtain 
                  needed                                                               maximum benefit from this “pulling” system, it was also 
                Time spent waiting - waste such as that associated                    proposed the formation of manufacturing cells or bringing 
                  with a worker being idle whilst waiting for another                  machines closer together in groups. The JIT system has 
                  worker to pass him an item he needs (e.g. such as                    continued to evolve and hence its applicability in a variety 
                  may occur in a sequential line production process)                   of industries. Also the notion that JIT is an inventory 
                Motion – waste associated with operator movements                     management system only has since been dispelled as it 
                  or employee movements on the shop-floor                              has come to be more than just an inventory management 
                Transportation/movement  - waste such as that                         system.  JIT has evolved into an operational philosophy 
                  associated with transporting/moving items around a                   that incorporates an improved inventory control system in 
                  factory                                                              conjunction with other systems such as [6]. 
                Processing time - waste such as that associated with                   
                  spending more time than is necessary processing an                       A set-up time improvement system 
                  item on a machine                                                        A maintenance improvement system 
                Inventory - waste associated with keeping stocks or                       A quality improvement system 
                  inventory                                                                A productivity improvement system 
                Defects - waste associated with defective items                        
                                                                                       3.2  Key elements of JIT manufacturing 
              Basics of the concept are that industries should produce                  
              what is needed, when it is needed and in the quantity that               3.2.1     JIT and the Kanban [4] 
              it is needed [7].  A company aims to produce what                         
              customers’ need that is, producing against customer                      JIT primarily applied to repetitive forms of manufacturing 
              orders as opposed to producing against forecasts. JIT can                in which the same products and components are produced 
              also be defined as producing the necessary units, with the               over and over again. The general idea is to establish flow 
              required quality, in the necessary quantities at the last safe           processes (even when the facility uses a jobbing or batch 
              moment. Customer demand triggers the production of                       process layout) by linking work centres so that there is an 
              goods and these goods feed into a buffer before they are                 even, balanced flow of materials throughout the entire 
              delivered to the customers.  Material movement is of great               production process, similar to that found in an assembly 
              importance in the JIT concept as shown in Figure 1:                      line.  To accomplish this, an attempt is made to reach the 
                                                                                       goals of driving all inventory buffers toward zero and 
                                                                                       achieving the ideal lot size of one unit.  One of the key 
                                                                                       features of a JIT system is the kanban which aids in this 
                                                                                       flow movement throughout the manufacturing system. 
                                                                                       There are two main types of kanban, the production 
                                                                                       kanban and the conveyance kanban.  The production 
                                                                                       kanban lets the workers know that more of a certain part 
                                                                                       needs to be produced.  The conveyance kanban lets them 
                                                                                       know that parts need to be transported to another 
                                                                                       centre. The kanban system is classified as a “pull system”  
                               Figure.1: JIT concept [1]                               in production, which means that when parts are need they 
                                                                                       are pulled and sent to the work station in need of them.  
              JIT is more than just a production and inventory planning                The starting point for a pull system is the customers and 
              and control system analogous to the well-known material                  then it works its way backwards all the way to the raw 
              requirements planning (MRP) systems. JIT pervades all                    material resources. Decisions regarding the number of 
              aspects of the production and inventory flow process,                    kanban (and containers) at each stage of the process are 
              covering not only the work-in-process (WIP) inventories                  carefully considered, because this number sets an upper 
              (parts), but also the flow of finished goods from                        bound on the work-in-process inventory at each stage. 
              manufacturing to distribution centres in the forward                      
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                       International Journal of Science and Research (IJSR), India Online ISSN: 2319-7064 
             3.2.2     Production scheduling within a JIT system                     3.2.6    Preventive maintenance 
                                                                                      
             The need to stabilize and level the master production                   Preventive maintenance (PM) as a management system is 
             schedule (MPS) with uniform plant is emphasised within                  of critical importance in the achievement of the objectives 
             JIT manufacturing. To create a uniform load on all work                 of JIT. Preventive maintenance involves the utilisation of 
             centres through constant daily production and mixed                     machines’ and workers’ idle time to maintain equipment 
             model assembly are some of the techniques used to                       and prevent breakdowns.  This tries to make sure that 
             maintain a uniform plant loading.  Demand fluctuations                  during production time no breakdowns are encountered so 
             are met through end item inventory rather than through                  as to meet the deliveries to customers.  Thus by utilising 
             fluctuations in production level.  Use of a stable                      the idle time production can go on undisturbed.  
             production schedule also permits the use of back-flushing               Introduction of fail-safe systems also greatly reduces the 
             to manage inventory where an end item’s bill of materials                                                                           . 
             is periodically exploded to calculate the usage quantities              down time in a manufacturing operation and enhance JIT
             of the various components that were used to make the                     
             item, eliminating the need to collect detailed usage                    3.2.7    The workforce 
             information on the shop floor [2].                                       
                                                                                     Flexible work force: workers should be trained to operate 
             3.2.3     Set-up time reduction                                         several machines, to perform maintenance tasks, and to 
                                                                                     perform quality inspections.  In general, JIT requires 
             Reduction or elimination of setup times is one of the aims              teams of competent, empowered employees who have 
             of JIT.  JIT aims for single digit setup times (less than 10            more responsibility for their own work.  The 
             minutes) or "one touch" setup. This can be done through                 interdependence of the factors above can be summed in 
             better planning, process redesign, and product redesign.                the diagram below: 
             A good example of the potential for improved setup times                 
             can be found in auto racing, where a NASCAR pit crew 
             can change all four tires and put gas in the tank in under 
             20 seconds.   The pit crew’s efficiency is the result of a 
             team effort using specialized equipment and a 
             coordinated, well-rehearsed process. In a manufacturing 
             system the single minute exchange of dies (SMED) has 
             been an area that has received widespread attention in 
             terms of research and application aimed at set up time 
             reduction. 
              
             3.2.4     Reduction of lot sizes 
              
             Reducing lot sizes (whether manufacturing or purchase) is 
             key in JIT production. Reducing setup times allows 
             economical production of smaller lots and close 
             cooperation with suppliers is necessary to achieve 
             reductions in order lot sizes for purchased items, since 
             this will require more frequent deliveries. The use of a 
             control system such as a kanban  system (or other 
             signalling system) to convey parts between work stations 
             in small quantities (ideally, one unit at a time) rather than 
             in large complete batches helps to enhance JIT as 
             materials move to the next work station without delay.                                                                            
                                                                                        Figure 2: JIT system elements inter relationship [2] 
             3.2.5     Zero lead times                                                
                                                                                     3.3  Benefit of  JIT in manufacturing 
             The reduction of lead times, which is the time it takes                  
             from the time a customer, places an order, to production                The ideal goal of JIT is that an enterprise’s business cycle 
             and delivery enhances the principles upon which JIT                     operates without interruptions and without non-value 
             manufacturing has been founded. Production lead times                   added time costs. Some of the more generic benefits in a 
             can be by moving work stations closer together, applying                manufacturing environment are [4] 
             group technology and cellular manufacturing concepts,                    
             reducing queue length (reducing the number of jobs                        Reduced set up times 
             waiting to be processed at a given machine), and                          Improved flow of materials throughout the 
             improving the coordination and cooperation between                           manufacturing system 
             successive processes; whilst delivery lead times can be                   Factory employees are multi-skilled 
             reduced through close cooperation with suppliers,                         Better consistency of production scheduling 
             possibly by inducing suppliers to locate closer to the                    Improved supplier relationships 
             factory.                                                                  Improved customer satisfaction levels 
              
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                      International Journal of Science and Research (IJSR), India Online ISSN: 2319-7064 
               Better quality products                                           more inventories might prove not to be a valid remedy as 
               Improved productivity                                             inventory holding costs may become prohibitive.  Too 
               Eliminates the cost of storage facilities and associated          much or too little inventory leaves an organisation at a 
                 costs                                                            competitive (or cost) disadvantage to competitors. 
               A culture of continuous improvement                                
               Less capital tied up in inventories                               Figure 4 shows that holding too little inventory will lead 
                                                                                  to an organisation not being able to meet customer 
             The market is a strangely fluctuating phenomenon and for             requirements (low customer service level) and whilst too 
             companies abiding by the approach of JIT, it is difficult            much inventory may lead to capital tie up and high 
             for them to cope with those fluctuating cycles of customer           storage costs that may affect the product price (or 
             demand. For instance, if the demand for a product goes               production cost) and possible loss or deterioration of the 
             suddenly up, companies using JIT won't be able to meet               product whist it is in storage.  JIT aims at obtaining the 
             them from stocks held, since they are used to keeping                optimal mix of customer service level versus inventory 
             small amounts of inventories.  Such challenges can                   that increases operational efficiency. 
             disturb the company’s overall potential to supply goods in 
             a timely manner or the capturing of that intermittent 
             market. 
              
             3.4  Inventory in manufacturing 
              
             Inventory can be defined as all the raw materials, work-
             in-progress, finished goods, assemblies and sub-
             assemblies in a manufacturing organisation’s production 
             system.  The goal of any manufacturing entity is to make 
             money; stock held in an organisation represents money 
             that is ‘locked up’ that might not necessarily translate to 
             actually cash. 
              
             Hence the ultimate goal of JIT is to eliminate such 
             activities so as to streamline all activities towards creating 
             value in the product. 
                                                                                      Figure 4: Inventory versus customer service level       
             3.5  Perceived disadvantages of inventory [5]                                                      
                                                                                  3.6  JIT and quality management 
             The tendency with most organisations that have to keep                
             some level of inventory is to keep more than what is                 A manufacturing company’s survival in an increasingly 
             enough or a high level of inventory. Figure 3 below gives            competitive environment closely depends on its ability to 
             an insight into the dangers associated with high levels of           produce highest quality products at the lowest possible 
             inventory.                                                           cost and in timely manner with the shortest possible lead 
                                                                                  times. Thus quality management has also become an 
                                                                                  integral part of JIT systems.  This has given rise to 
                                                                                  concepts such as JIT based quality management.  Quality 
                                                                                  management can be defined as part of the overall 
                                                                                  management function that focuses on the achievement of 
                                                                                  results aimed at satisfying the needs, requirements and 
                                                                                  expectations of stakeholders in line with the 
                                                                                  organisation’s quality policy and objectives.  This 
                                                                                  includes the organisational practices, procedures, 
                                                                                  processes and resources for developing, implementing, 
                                                                                  achieving, reviewing, maintaining and improving the 
                       Figure 3: High levels of inventory [2]                     organisation’s quality capabilities and performance (ISO 
                                                                                  9000 standard, 2000).  Thus an organisation in pursuance 
             Inventory can mask or cover a lot of problems within a               of JIT production will in essence be in line with some if 
             manufacturing system. These problems may include                     not part of the requirements of a QMS. JIT based quality 
             machine breakdowns, long set-up times, long lead times,              management has been defined as the combination of 
             quality defects, problems associated with scheduling and             inventory control, quality control and production 
             even problems associated with the selling and marketing              management functions that makes sincere efforts for 
             of products.  With a high level of inventory such                    quality improvements in two ways. Managers motivate 
             problems are not immediately recognised and at times                 workers to think quality first and then production rate 
             these later can manifest in a number of ways such as tied            second [7]. 
             up capital, storage space problems and loss or                        
             deterioration whilst in storage. However in very                     3.7  Lean management and JIT 
             competitive markets reducing uncertainties by holding                 
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