Kanban Pull System
Abstract Kanban Pull System is a method of controlling the flow of production through the factory based on a customer’s demand. Pull Systems control the flow of resources in a production process by replacing only what has been consumed. Kanban Pull System is a system that suitable for SMIs Company in Malaysia. Next, is discusses about Kanban Pull System Process for SMIs company in Malaysia. Kanban is a sign, symbol, or in the production process trigger signal is generated at the time of lean production and supply.
Is a production Kanban pull or Kamban of JIT, Kanban signals from one process to the next process, to produce more parts in the main method. Besides that, Kanban Pull System has a lot of benefit for SMIs Company in Malaysia such as reduce overall inventory, reduce work in process, reduce order turnaround time, increase customer satisfaction, and improve cash flow. In addition, SMIs Company in Malaysia can use Triangle Kanban Pull System for success their business. keywords: Kanban Pull System, Kanban Pull System is a system that suitable for SMIs Company in Malaysia, Kanban Pull System Process for SMIs Company in Malaysia, Kanban Pull System is a system that suitable for SMIs Company in Malaysia Kanban Pull System has a lot of benefit, and SMIs Company in Malaysia can use Triangle Kanban Pull System. 2. 0 Introduction Global manufacturing enterprises continue to increase their production and operation to recover, especially in the automotive and computer industries a competitive advantage.
Industry challenges, e-commerce and customers via the Internet Order transferred to the configuration of the production equipment and make-up of environmental safety. Traditional large-scale production is not particularly adapted to clients’ needs changing; it depends on forecasts of future demand and scheduling system to meet the expected demand for production work. Production systems, often with an inventory of products. In addition, a high level, and the service is no longer taken from time to delivery.
In contrast, only depend on current production, cause the release of work into the system, and “pull” system, to meet real demand. Timely production is better for the production of ideas, arguing that the right product at the right time and right amount of product that can meet customer needs changing. Reconfigurable systems enable rapid and low-cost replacement for capacity allocation, the desired product. Manufacturers are also moving off-line, and the need for suppliers to deliver the module sub-assemblies.
Therefore, the pull system manufacturing and installation, basic understanding is essential for the orderly implementation of the paradigm. Industrial Engineering degree courses in general, including analysis of production and management process, but time and submits the concept of lean manufacturing principles. Many students also take language simulation, random number generation, input modeling, verification and validation strategies, and the analysis of simulation output, which includes course.
However, little or no text books discuss the pull system using a simulation model, control, and analysis of materials. This article attempts to address this deficiency, and can be used as a simulation, and production and management courses added. This simulation model used to describe the mechanism of exciting the system, provide the reader with a “hands on” approach to the kanban system. And Zazanis Spearman (1992) provides a discussion of more advanced, push, pull-pull system to improve performance over conventional propulsion system and the current theory of motivation.
They help this paper argues that the analysis of interesting systems, and provides a number of suspects, to encourage readers to consider, and pull the article describes the simulation model. 3. 0 Kanban Pull Systems Kanban Pull System is a method of controlling the flow of production through the factory based on a customer’s demand. Pull Systems control the flow of resources in a production process by replacing only what has been consumed. They are customer order-driven production schedules based on actual demand and consumption rather than forecasting.
Implementing Pull Systems can help you eliminate waste in handling, storing, and getting your product to the customer. Pull Systems are an excellent tool to use in the areas where cellular or flow manufacturing cannot be achieved. Kanban is a sign, flag, or signal within the production process to trigger the production and supply of product as part of Just in Time in Lean manufacturing. Kanban or Kamban is the main method by which pull production is realized within JIT, the Kanban being the signal from one processes to a preceding process to produce more components.
Most people have seen Kanban in operation but just do not realize it, there are two well known retail chains that spring to mind when considering Kanbans, the first is the chain that can produce your spectacles within the hour while you wait; your order is dropped into a tray, this tray is the Kanban, it is moved from one process to the next, each step being completed as per your specification within the hour. If there are no spare trays the assistant within the store knows that they cannot produce your glasses within the hour as capacity is all used up.
The second example is that of a certain fast food / burger joint, between the server and the kitchen is what is known as the “burger regulator. ” As the servers remove burgers from the regulator this is the signal to produce more to the kitchen behind. Batch sizes for production are changed during the day to match expected demand for peak and slow periods, if used correctly (many of the youngsters in these places seem to think they know better than the system! ) 95% of customers should find their order freshly available without having to wait. Figure 1: Kanban Pull System
Figure 2: Kanban systems combined with unique scheduling tools, dramatically reduces inventory levels, increases turns, enhances supplier/customer relationships and improves the accuracy of manufacturing schedules. 4. 0 Should Every SMIs company in Malaysia Use Kanban Pull System? The next question to address is should pull systems be implemented in most SMIs company in Malaysia. The two types of pull systems respond slightly differently to changes in volume and product mix. The major disadvantage for both types of pull systems is that they require fairly steady product flow.
Kanban is typically restricted to repetitive manufacturing where material flows at a steady rate in a fixed path. Large variations in volume or product mix destroy the flow and undermine the system’s performance goals. If there is too much WIP, the goal of minimizing WIP in the system is not achieved, and financial flexibility in dealing with scheduling and engineering changes is lost. If there is too little WIP, throughput goals cannot be attained. While still requiring a relatively steady volume, is a little more resilient in handling changes in product mix.
The difference between their capabilities of handling product mixes has to do with the individual products having different bottlenecks and how WIP is controlled within the system. Questions to consider when assessing whether a pull system should be adopted include: • How often do design, engineering and schedule changes occur? •What are the economic consequences of maintaining the current system compared to converting to a pull system? • Can a pull system reduce overall lead-time compared to a push system? •Are suppliers reliable enough to support just-in time delivery of raw materials or subcomponents? Is the production system reliable, or does it suffer frequent breakdowns that stop production? • Are labor and management committed to making the changes needed? • How often and how significantly does the product mix change? In situations where a pull system is found to be acceptable for a facility, a decision of which type of pull system to implement must be made. As discussed previously, the choice depends on the level of WIP control desired (at the individual workstation level, or a “black box” system level). 5. 0 Kanban Pull System Process for SMIs company in Malaysia
Kanban is a sign, symbol, or in the production process trigger signal is generated at the time of lean production and supply. Is a production Kanban pull or Kamban of JIT, kanban signals from one process to the next process, to produce more parts in the main method. Most people have seen the billboard operations, but did not realize it, there are two well-known retail chains, spring to mind when considering signs, the first chain to produce your glasses in an hour, while you wait; order down to the tray, tray this kanban, they move to the next process, each step in an hour to complete, according to your specifications.
If no alternate storage tray assistants know that they cannot come in one hour is your ability to walk out of the glass. The second example is the fast food / burger venture between servers and kitchen, which is known as the “Hamburg rules. ” Hamburg because the server was removed from the regulations, to produce more in the kitchen behind the signal. On that day, to meet expected demand at the summit and slowly, if used correctly (young people in these places, many people seem to think they know better than the system! 95% of customers need to find the size of the production fresh they may have to wait for change orders. 6. 0 Benefit of Kanban Pull System for SMIs company in Malaysia 1. Reduce overall inventory 2. Reduce work in process 3. Reduce order turnaround time 4. Increase customer satisfaction 5. Improve cash flow 7. 0 Successes of Kanban Pull System for SMIs company in Malaysia A maker of fine table linens was able to slash its average order turnaround time from 3-weeks to 3-days using a Pull System. The changes eliminated bottlenecks in production and increased responsiveness to customer needs.
A manufacturer of high-quality packaging machinery implemented a multi-faceted Lean transformation. A Pull System was used to smooth the flow of WIP. The changes decreased WIP by 62% and dramatically increased the number of orders completed each day. Pull Systems/Kanban-and other lean techniques-were implemented by a manufacturer of custom fiberglass and vacuum form products. These changes increased productivity by 20%, reduced inventory by 53%, decreased lead-time by 63%, and far exceeded their targeted goals. 8. Simulation Models of Kanban Pull System for SMIs company in Malaysia Simulation models have been developed in Arena 3. 5 and tested in Arena 4. 0 for the Kanban Systems in Figures 1 and 2 respectively (Marek, 2000). The reader is assumed familiar with the basics of simulation programming and analysis. The code for these models is presented in the following sections for the reader to obtain a “hands-on” feel for the different pull mechanics in each system. The serial manufacturing systems being modeled contain four workstations, and must produce two types of products.
The make-to-order production facility has reconfigurable manufacturing equipment, allowing rapid and low cost changeovers to switch between product types. The setup times for changing between product types are considered to be zero on the assumption that the products are quite similar. This is a realistic assumption, for production line designers are now examining the value of agile tooling, fixtures, and material handling, so that any part in a general family may be produced on the line if the designed part fits within he line’s production envelope. For this reason, product types are not batch processed on a forecasted basis, but are processed on a first-come first serve (FCFS) basis as orders arrive. Product types are assigned from a discrete probability distribution for each arriving order with 70% type 1 and 30% type 2. Process times at each workstation may depend on product type. Machine breakdowns and supply chain failures are currently not considered. The variance reduction technique of Common Random Numbers (CRN) (Pegden, et al. 1995) is employed to synchronize usage of random numbers in the Kanban Systems so that the systems are compared under similar conditions. Each system observes the same sequence of arrivals of type 1 and type 2 jobs and uses the same processing times for jobs at each workstation. This approach is often justified for scenario analysis whereby the analyst seeks to compare two or more alternatives (systems) and control specified parameter sequences while permitting other system parameters to vary.
By designing the various simulation runs, the analyst can better distinguish the impact(s) of specific changes in the scenarios. Throughout the remainder of this paper, specific ARENA modeling constructs are used to define the modeling approach. The ARENA SEEDS element controls the six random number streams used (See Table 1). By using common random numbers, randomness in experimental conditions is reduced, and any measured differences in the two systems are due to the pull behavior and card control level used. Stream| Seed| Purpose| 1| 2323| Job Inter-Arrival Times| | 4545| Workstation 1 Processing Times| 3| 8080| Workstation 2 Processing Times| 4| 8181| Workstation 3 Processing Times| 5| 1717| Workstation 4 Processing Times| 6| 1974| Job Type| Table 1: Random Number Streams 9. 0 Kanban Pull System Focus for SMIs company in Malaysia A Kanban card can be generated to identify production of part(s) to replenish in-house inventories, a withdrawal of product for shipment to a customer, or to signal the replacement of raw materials and components. Using Kanbans there must be a purchase or an order to generate the card.
The product is pulled through the production sequence based on the order from the customer. Pull/Kanban is a part of the Lean Production or Just-in-time (JIT) manufacturing process, applying Lean principals to eliminate waste. Every method in the Lean production system focuses on the elimination of waste. Lean principals should not be limited only to manufacturing operations, all areas of a company can benefit from the application of Lean principals. Reduction of waste ensures lower costs, higher quality products, and better service and delivery. 10. Triangle Kanban Pull System for SMIs company in Malaysia The method that Toyota facilities would follow most of the time in connecting a batch process to a downstream assembly process is called the triangle kanban. Below is an example in rough detail of how to evaluate to use this method for implementation (See LEI Workbook Creating Level Pull for a more detailed explanation). The example assumes you have a batch machining department feeding some type of final assembly. The machining department has five machines building 11 totally different product variations.
The demand for each product varies significantly, as does the standard pack quantity of each part. The setup time for changeover is about three hours. 1. Take the 11 part numbers and dedicate them to the five machines. (Ideally for example four machines will have two part numbers to run and one will have three part numbers to run, but this depends upon volume and mix, etc. ) 2. Now let us take one machine which now has several dedicated part numbers assigned to run on it. 3. Create a single triangle kanban for each part number including the following information (see picture below). . Part number b. Part description c. Inventory location d. Machine to be run on e. Space for date triggered to be written f. Tool number g. Lot size* h. Trigger or reorder point* *We’ll calculate these below 4. Determine the required daily run time for each part number. Calculate your average daily demand for each part number. If you haven’t leveled the build in final assembly it’s probably wise to add some amount in to cover demand variation. Let’s assume that you have two shifts of eight hours available production time which equals 16 hours of production (simplest case).
If you have two part numbers on a machine, you can derive required production time based upon average daily demand and the cycle time to run the 3 part number. For example, let’s say, for ease of calculation, that required production time adds up to 10 hours. 5. Determine the time available for changeovers. In the simple case of 16 hours of production and 10 hours of demand it leaves six hours for changeovers each day. You should incorporate any average down time and scrap you have in the short run – but eliminate this in the long run. Thus, in our simple case (ignoring downtime, etc. you have available time for two changeovers daily or roughly one per shift under current calculations. 6. Determine your lot size for each part number. There are different ways to do this but for simplicity I will only describe the easiest. In this case your lot size is simply set at one day of production since you probably have two part numbers on this machine and will average two changeover events per day. In essence you are making every part ever day. If you had 10 part numbers on the machine and only two changeovers per day you would have lot sizes of five days. . Determine your trigger point for replenishment. To do this, add up the run time for the longer of the other components, add the changeover time, and add the time to make the first container and get it reliably back into the market. This is the minimum level you can establish for a replenishment trigger point for product. (An average trigger point might be 300 pieces. ) The system works by hanging a single triangle kanban at the trigger point in the inventory location. When the trigger point is reached, material handling takes it back to the producing machine.
The kanban is hung on a rail at the machine and dictates what to build next and the lot size. The triangle pull system has many advantages. It is virtually self-running once established as long as average demand does not change. If it does, change your lot sizes accordingly. Also, the triangle helps stabilize quality since product is dedicated to a machine, and it takes out some variability but you can choose to run product on other machines. The down side is that the inventory in the market is not visible at all times since there is no batch board with cards.
You do see, however, how many kanban are hanging on a rail at the machine which is a good indication of inventory depletion and a tool for visual control. Furthermore, there is only one kanban per part number to manage. Other minor challenges include, of course, figuring out the die maintenance schedule (for some types of machine) and what impact this will have on the schedule. Also you must figure out a simple signal to reliably bring any needed raw material to the machine. Figure 3: Sample Work Flow Using Triangle Kanban for Scheduling
Figure 4: Triangle Kanban Detail In the end, you must decide what is the main goal is of implementing the pull system. Each of the three described ways works in terms of scheduling a batch process in conjunction with a market but each has a slightly different emphasis in mind. It might be worth the time to calculate the inventory levels, run times, operating rules for each of the three different ways. Construct a simple matrix, evaluate each of them in accordance with your priorities, and select the one that best fits your needs and company ability. 1. 0 Conclusion At this point, the reader should feel comfortable with the basic concepts, modeling, and card reduction techniques for Kanban systems. The major advantages of implementing a pull system include reduced cycle time variability, and economic flexibility to make engineering and design changes. While Kanban systems maintain tighter control of system WIP through the individual card resources at each workstation, Kanban systems are easier to implement and adjust, since only one set of system cards is used to manage system WIP.
The card reduction strategy discussed also demonstrates how simulation can be used as an effective decision support tool for production operations. Additionally, modeling pull systems with virtually any simulation language can present challenges to the analyst in that one must be somewhat innovative in the construction of the model and fully understand how to apply the given modeling constructs to effect a valid model. ARENA was chosen as the underlying simulation language because of its wide applicability in industry, and its ease-of-use as a teaching language.
The authors’ experience is that it is straight forward to learn additional simulation languages after learning concepts of process flow and modeling techniques using a first simulation language. The Kanban systems logic should be relatively easy to implement in other simulation languages (such as AutoMod, Witness, ProModel, Simul8, etc. ) that specialize in modeling manufacturing process flows. Thus, by studying the example problem contained herein, a greater insight and appreciation for the logic and application of the modeling constructs (especially in the ARENA frame) are obtained. 2. 0 References Marek, R. P, Elkins, D. A, Smith, D. A (2001). Understanding The Fundamentals of Kanban and Conwip Pull Systems using Simulation. Spearman, M. L, Woodruff, D. L, Hopp, W. J, (1990). Conwip: A Pull Alternative to Kanban. Deleersnyder, J. L, Hodgson, T. J, Malek, H. M, Grady, P. J. O (1989, September). Kanban Controoled Pull Systems: An Analytic Approach. Karmakar, S. U (1986, June). Interating MRP with Kanban/Pull Systems. Working paper Sereies No. QM8165. Krar, Steve. Pull (Kanban) Systems Smalley, A. Connecting Assembly with batch Processes via basic Pull Systems