Value Engineering in Product Renovation

Transcription

1 Value Engineering in Product Renovation Fang-Lin CHAO, Chien-Ming SHIEH and Chi-Chang LAI Department of Industrial Design, Da Yeh University TAIWAN, Abstract: The value engineering approach is selected as a communication platform between industrial designers and engineers. Value engineering is based on function analysis to optimize function and cost ratio in particular situations. Quantitative evaluation of value-engineering provide better communication in the concept generation phase. The evaluation of weighting factor comes from function rank, customer problem rank and manufacturing cost. The criterion can be chosen by project situation to guide innovation s direction. Two kinds of criterion, value increasing and problematic reduction, were utilized during the trimming process. Both criterions are helpful in generating new concepts. The design concept was implemented with a three-dimensional modeling tool. Evaluation results show that performance increase by 14% with the proposed design. This approach is applicable in product re-design phase with clearly specified components and function relationships. Key words: Product evaluation, Functional Analysis, Value engineering 1. Introduction Design is what we do when we solve a problem. Design and engineering are linked together in most of projects. When designers solve a problem or satisfy a need, they often use appropriate engineering technology. Appropriate technology can be low or high technology. It is any type of technology that suits the way it is being used. Therefore design evaluation plays an important role in determining the situation and in choosing better design solution. Industrial designers and engineering designers have different educational backgrounds. Industrial designers tend to be subjective in their judgment of concepts, whereas engineering designers tend to implement systematic approaches. Sometimes the weak communication link between the two fields causes misunderstanding during the product renovation process. The common process in product redesigning is shown as follows: 1. Think about the problem 2. Collect information, think of possible solutions 3. Choose the best solution 4. Plan and make the prototype solution 5. Test the prototype solution When the designer or engineers do not have a consistent perception of the problem or the possible solutions, the contradiction appears. This can easily happen during the above steps 1 to 3. For instance; Which idea is the best? Which idea solves the problem best? Which one can be made easily and within the time limit? If cost were important, which would be the cheapest?

2 Are the designs safe? Will people like it and pay for it? These questions are difficult to answer for both designer and engineer. In this study, the Value engineering approach [1] is selected as a communication platform between industrial designers and engineering designers. Expanding on the meaning of value, the product needs to be not only mechanically efficient but also to satisfy human needs, which are often irrational. Value engineering is based on function analysis and customer information to optimize design related factors in particular situations, and has been utilized in the construction industry for many years. Mr. Lou [2] studied value engineering and risk management. In a complicated system development, the decision is made through an organization structure, which consists of people with different backgrounds. The undetermined factors in the project often confuse the team member in decision-making. Value engineering can be utilized as a systematic development framework and can be helpful in risk management. Mr. Kou [3] studied the vertical cooperate framework in Taiwan s electronic industry. The research investigated the switching mode power supply industry to find out how to use value engineering to enhance the product function, reduce the product size and keep the thermal management ability within a reasonable range. 2. Method In this study, Techoptimizer 3.5 software is selected as a value-engineering platform. The industrial designers and engineering designer built the design information together and shared the data through the project manager module in the software. Function analysis is carried out to optimize function and cost ratio in particular situations. The basic function modeling and concept generation steps include (1). Create a component model, (2) Identify the main function, (3) Assign function to relevant interaction, (4) Select component to eliminate, (5) Select trimming conditions to redistribute functions, (6) Verify the results of the trimming process. 2.1 Functional modeling Function modeling analyzed the product based upon the functions of its components and outside elements [4]. These outside elements, which intersect in a relevant way with the components of the system, are called supersystem elements. By defining functions, we are able to describe the problematic interaction and the performance of the system at a higher level of abstraction. Functions are relationships between components and are performed to affect the parameters and the characteristics of the components. Functions can be described as useful and harmful functions. The qualitative definition of function is then provided the actual value of function s parameters, the acceptable value of parameter as well as the ideal or target value. The ideality or value equation is: Ideality = Function / (Cost + Problems) Inexpensive high performing components without series problems are more valuable than expensive low performing components with series problems. Trimming is a method for improving systems based upon the elimination of components that are

3 problematic, costly or unessential in the system. The criterion (called the Trimming factor) for choosing a component to trim is found by using the following standard value formula: Trimming factor = F*F / (P+C). where F=function rank, P=problem rank, and C=cost. The component with the lowest criteria value should be trimmed first. The functional rank calculation is dependent on both the number of its useful functions and individual rank of these useful functions. Consequently, if a component performs many functions and these functions are basic functions, this component has a high function rank. For each component, the problem rank is proportional to the number of harmful functions and the level of performance of useful functions. If the difference between current parameter and desirable parameter is considerable, the problem rank will become high. In this investigation, a problematic criterion is proposed from the user group interview results. The formula is based on the customer s opinion of the importance about the product functional elements. Trimming factor = F/ (4*P+2*C+V). where F=function rank, P=problem rank, and V=volume of the parts. To redistribute the useful functions that the eliminated components used to perform, while applying trimming conditions, we must ensure that the essential functionality of the system is maintained while simplifying the system. The basic three trimming rules are: 1. The function recipient does not need to exist 2. The function recipient can deliver the function itself 3. The function can be delivered by other elements 2.2 Test Vehicle Evaluation Steps Women s security device is chosen as a test vehicle in this investigation. The reasons are: (1) its semi-mechanical operation mode, (2) consist reasonable complicated parts or components, (3) the evaluation can be done by user directly. Women usually carry security device in her bag or pocket. When a possible dangerous situation happens, the device can be activated to perform a significant sound and light effect to prevent a possible further attack. The evaluations in redesign process are described below. Product value evaluation with customer A questionnaire is given to a group of 100 women with different backgrounds (housekeepers, students, office workers). This helps us to understand their opinions on the product and their expectations. From the statistic calculation, the user s priority result about the product is as follow (1) price, (2) form, (3) volume and size of the product. The user s expectation of additional functions are (1) light, (2) key attach, (3) handing tool, (4) timer, (5) radio. Cost model of the parts, tooling and material cost We analyzed the parts of the product and estimated the production cost of each part by expert interview.

4 For example the cover is made by injection molding. The molding tools, material cost and the related processing cost are then estimate by manufacturing expert. The estimated per unit cost of each component is shown in Table 1. Table 1. The estimated per unit cost of each components No. Component Function number Cost 01 Upper case Protect main unit Lower case Support Switch Selection, control Hook Hang with body Light frame Cover light bulb Locker bar Activate alarm Bulb set Provide light Plastic plate Light reflection Base conductor Electrical path Contact Support battery Spring Contact beeper Conduction pad Conduction Beeper Generate sound Skew Support Wire Connect Outer package Storage Labor cost assembly The functional model is build as shown in Figure 1. Figure 1 Function model of the Women s security device

5 Extract of rank index The functional rank calculation is dependent on both the number of its useful functions and the individual rank of these useful functions. The functional rank is calculated by function model [5]. If the component acts directly, the rank of the action is basic function. If the component acts on a component that performs a basic function, the rank of its action is auxiliary-1. For each component, the numerical ranks for each action that is performed are added and the sum is the functional rank of the component. For each component, the problem rank is proportional to the number of harmful function and the level of performance of useful functions. In this study, instead, the problem rank is gathered from the customer evaluation. Thirty people are invited to practice the device under test within 10 minutes. Then people answer questions about the importance of the function and the operation convenience (actual and expected). Then the problem rank of each component can be defined as: Problem rank = (Expect condition Actual condition)* Importance The calculated data are then normalized on a 1-10 scale for further application. We can calculate the Trimming factor by combining those parameters with cost rank. 3. Results Trimming factor results are shown in Table 2. The criterion can be chosen by project situation to guide the innovation direction. Two kinds of criterion, value increasing and problematic reduction, were utilized during the trimming process. Both of them are helpful in focusing on generated new concepts. The component with the lowest value should be trimmed first. Table 2 TechOptimizer Trimming factors Component Function rank Problem rank Cost rank Volume Evaluation value increasing Evaluation problematic reduction activate bar bulb fixture hanger housing beeper switch bulb During the trimming process we have to redistribute the useful functions that the eliminated components used to perform. The basic three trimming rules are employed in trimming process. Every possibility is considered and the most valuable one is elected for further implement. As shown in Figure 2, the function of activate bar can be delivered by other elements (hanger). This means that the activate bar s

6 function can be delivered by the hanger. Consequently, the number of components is decreased, which reduces the cost too. (a) (b) Figure 2. The trimming example of the (a) activate bar and (b) switch. Two kinds of criterion, value increasing and problematic reduction, were utilized during the trimming process. These formulas are not derived from analytical approach. The formulas can be built based on design management judgments. This is strongly affected by the situations of individual project. Both criterions are helpful in this project. The design concept was implemented with a three-dimensional modeling tool. Based on the idea generated above, the 3D computer model of the proposed design is implementing on Alias (Figure 3). As shown in results, concepts evaluation indicates an improvement of 14% with the proposed design. The useful function is increased by 8%. During the trimming process, we found that a quantitative

7 evaluation allows the value-engineering approach provide helpful communication between team members. Figure 3. Original product and redesign 4. Discussions and Conclusion Through the study, we find that functional modeling can provide industrial designers and engineering designers a more solid interface. Quantitative evaluation lets the value-engineering approach provide better communication in the concept generation process. The trimming criteria s weighting factor comes from function rank, customer problem rank and manufacturing cost. The trimming criterion can be chosen depend on the characteristic of product. Two kinds of criterion, value increasing and problematic reduction were utilized during the trimming process. Both of them are helpful in focusing on generating new concepts. The functional model and evaluation process can help to build a more systematic approach in problem definition and concept generation. This approach is applicable in product re-design phase with clearly specified components and function relationships between components of product. References 1. Jose Arocha, Introduction to the Innovative Technology of Design, Invention Machine Corporation, 1-6, (1999). 2. S.H. Lou, Value Engineering in Risk Management, master thesis, Taiwan University, (2001). 3. M.H. Kou, Value Engineering and its application in electronic industry, master thesis, (2001). 4. Y.Shimomura, Representation of design object based on functional evolution process model, Journal of Mechanical Design, 120(6), (1998). 5. TechOptimizer 3.5 user guide, Invention Machine Corporation, 2-8, (2000).