Value stream mapping in built environments
Manufacturing is an undertaking that uses tools, chemicals, machines, and biological means in producing goods for sale or consumption. Since manufacturing process is the source of products, it has become a crucial step in business. Every organization aims at reducing the cost of production by reducing the operational cost, labor costs and other factors of production in product improvement. The two common approaches used are Value Stream Mapping (VSM) which depicts information and inventory flow improvement and Six Sigma. Six Sigma is a method of improvement that employs five steps of problem analysis; define, measure, analyze, improve and control. In this report, we shall discuss the two methods of product improvement. A case study of a company called Xam is picked in six sigma analysis. The report expects to find that VSM and Six Sigma are invaluable methods of product improvement.
Manufacturing is becoming a more crucial in the market and this makes companies to concentrate due to the resulting competition. The production through manufacturing has to be increased in efficiency, however, high levels of quality needs to be maintained. The rise in production costs such as labor costs, operating cost in many industrialized countries has made them to outsource their most of the operations. The companies may outsource these operations to countries with lower production costs and wages. Another way to reduce cost and maintain competitiveness in the market is to use lean manufacturing. Lean manufacturing is a method manufacturing that tries to reduce wastes in production. These waste can be can result from operations, long lead times, reworking, defects and material waste (Singh, & Sharma, 2009)
VSM is a of flow chart that shows and improves the flow of the inventory and information. The mapping uses the symbols which are known as language of lean.
Purpose of VSM
The aim of employing VSM in manufacturing is to provide the optimum value to the client in terms of goods and services. This is achieved through the value creation in processes through reduction of wastage in designing, building and sustaining quality in production (Singh, & Sharma, 2009)
Reasons for Using VSM
First, the improved events creates a localized improvement which are strengthen by visual stream mapping and analysis. VSM also provides strength through vision plans that links all the activities in a production line. Secondly, the many companies that uses lea conversions have noticed a deficiency in using the improvements events alone. This has called for the use of Value stream mapping. Finally, the VSM analysis acts as a tool that helps in seeing waste and thus be able to eliminate it (Singh, & Sharma, 2009)
The value that’s being analyzed should be of the highest quality, produced at the right time and sold to the customer at an appropriate price.
Principles of Value Stream Mapping
The following five principles are use when constructing a VSM
- The value from the standpoint end of the client need to be specified.
- The value stream for each products family is specified
- The product is made to flow so that the customer can pull to allow one to concentrate on perfection.
(Singh, & Sharma, 2009)
Symbols used in Value stream mapping
This shows a scheduling of central production, operation, person or department.
The icon shows the operation, machine, process or department through which the material flows.
This show the operator. It depict the number of operators required work in a particular process.
Supplier or Client icon
This icon represents the customer when in the upper right and shows the supplier when in the upper left and the usual end point for the material.
Kanban Post Icon
This symbol shows where the kanban signal reside for picking. The symbol is normally used in a two-card systems inn exchanging the withdrawal and the production kanban.
Sequence Pull icon
This symbol shows the pull system that gives instructions to subassembly processes to generate a predetermined quantity and type of a product. This is typically one unit without using a supermarket.
The icon shows operation scheduling using ERP or MRP systems. Other centralized systems can also use the same icon.
The icon represents the process of material from one process to the next in production.
This shows the inventory between two processes.
The arrows show either the movement of materials to the factories or the movements of finished products from the factories to the clients.
This shows the kanban stock point normally referred to as “supermarket”
(Singh, & Sharma, 2009)
Steps of Value Stream Mapping construction
The following steps are taken when constructing a VSM
- The first step is selection of the sponsor and setting of expectations.
A person responsible for making decisions, arbitrate solutions and planning the project is appointed. The guy selects the projects that will mapped and should have an idea of the real target.
- A team is selected.
A team that is composed of every area is selected for full representation i.e. purchasing, sales and ware house departments.
- Then the process to be mapped is selected.
This involves selection of the process to be handled. This may include; service oriented organizations, logistics and manufacturing.
- The data is collected and the current state map produced.
The necessary information regarding the process such as inventory, customer demands and materials information should be acquired for generation of the current state map. The future state maps will use the information acquired hence precision is needed in data collection.
- Critiquing of the current state
Suggestions are made on the present ideas to identify the areas of wastes in the system.
- Mapping the future state
The future state map is compiled basing on the present/current state map and critiques.
- Creation of Action plan and Deployment
Using the future state map, a viable action plan is considered and implemented.
- Results Measurements
The result is rated to see that the expected benefits are realized. The changes that were made are reviewed and the benefits analyzed.
(Singh, & Sharma, 2009)
Six sigma is a tool that is used to reduce the variations in a process. It is a tool that deals with improvement. It involves the use of statistical tools to help the management predict the outcome of a process in an organization. The tools can be used every now and then to clarify the elements that causes such problems and by so doing look for ways of removing them. The elements that are usually analyzed include quality control, production lead time among other factors of business. The six sigma strategy has five steps; define, measure, analyze and control normally abbreviated as (DMAIC) (Chen, Chang, & Huang, 2011)
The top management begins by defining the process. This involves asking the questions regarding the type and who the customers are for a particular product. They shall then identify the problem through customer feedback and then strategize the company’s mission, determine the client’s requirements and set the goals of achieving them.
This is the key transitional step in the six sigma policy. The problem is refined through inquisition for the root causes and this helps in finding the solutions to these problems. The key features of a system are grouped, measurements systems are proved and data collection is done.
The data collected is analyzed in this step. The project team shall use the data analysis tools and techniques to determine and verify the root causes of the problem being studied. For this purpose, the members of the team needs to come up with some hypothesis, identify the few core causes and finally authenticate the hypothesis.
The step aims at improving the process. Solutions to the problems identified so far are improved and changes are made to the process. The team members have the task of developing the ideas that remove the root causes, test the solutions and harmonize the solutions to yield better results. They then judge if the changes are beneficial or not and if another set of changes are needed.
This the last step of the six sigma. If the system is performing under a required and realistic level, a control measure is put to sustain it. This is done when the improvements and results made in the system has been documented. The team needs to establish measures of maintaining the performance and correction when deem necessary. This step is necessary, otherwise the process may revert to its original state.
(Chen, Chang, & Huang, 2011)
A company called Xam manufactures food products known as pork buns. The company wants to reduce the operational cost to improve financial returns and increase the competitive ability in the market. They decided to implement the six sigma in achieving their desires. A committee was selected to handle the project. The key issues they discussed were reducing the accounts receivables collection cycle, lowering rates of products defects, improving customer satisfaction, reducing the recruit cycle time and reduction of new product development time. The following phases were followed in addressing the product problems.
Results and Discussion
The feasible scope of the project was defined and this includes setting the projects goals and objectives. Pareto charts were used to define the hierarchy of attending the problems. The primary problem that was that the buns was due to shrinkage. After the scope project was obtained the goals had to be set; project financial and consequential indices. In this case, the goal was to reduce the defect rate of shrinkage. The time series data for shrinkage was collected. It showed that there was low shrinkage defects in the beginning which rose with time. The objective of the phase was to reduce the defects by 50% in two months. After setting the goal, financial index was then calculated accordingly. Finally, the consequential index takes note of effects that mat occur in trying to reach the target (Chen, Chang, & Huang, 2011)
Figure 1: Pareto chart (Chen, Chang, & Huang, 2011)
In this phase, the project situation as a whole is comprehended. Process flow diagram (PFD) is used was used to discussed the related flow processes of the product. A process map is established for inputs and output consideration is constructed for use in cause and effect analysis. Basing on the PFD, and the flow diagram, the members discussed the factors that may have caused the bun to shrink and the results were summarized in a fish-bone diagram as figure 2. The major problems forms the ribs of the fish while the main problem is the fish head (Shrinkage).
Figure 2: Fish bone diagram (Chen, Chang, & Huang, 2011)
The variables were then analyzed. In statistical analysis, the small frozen buns were collected through sampling out each from the container plate. Each bun was re-steamed to test the whether the bun would shrink or not. Also, the type of steaming box and pressure were collected in that level. Among other factors such as dough sheet rolling, ferment time, volume of input ice water and steaming time, the shift seemed to be the main factor in accelerating the defect rate.
A series of integrated experiments were performed in investigating the best approach of improving the quality of the bun. Stuffing temperature, ferment time, volume of input ice, times for dough rolling and steaming time were selected for improvement analysis. The results showed that the most critical factor was input ice volume.
Figure 3: Design of experiments analysis (Chen, Chang, & Huang, 2011)
After the improvement phase the factors that causes shrinkage of the buns were proposed. The actions were then implemented in the manufacturing process and the results were monitored in the control phase (Chen, Chang, & Huang, 2011)
VSM and Six sigma are tools and techniques that are mainly used in manufacturing a product that is desired by the customer. They guide on the proper steps and approaches that are followed in any production set up. Both method aims at improving the products in order to meet the client’s need. Through implementation of the two approaches, the organization will realize reduced operational cost, quality products, low production lead time and optimum profits.
- Chen, S., Chang, L.,& Huang, T. (2009). Applying Six-Sigma methodology in the Kano quality model: An example of the stationery industry 20(2), 153-170. Doi-10.1080/14783360802622847
- Singh, B., & Sharma, S. (2009). Value stream mapping as a versatile tool for lean implementation: 13(3), 58-68. Doi-10.1108/13683040910984338