Product Planning & Development (21-423)

Product Planning & Development (21-423)
Advanced Manufacturing Laboratory Department of Industrial Engineering Sharif University of Technology Session #16

Product Planning & Development (21423), Session #16
Course Description Instructor Omid Fatahi Valilai, Ph.D. Industrial Engineering Department, Sharif University of Technology , Tel: Website: Sharif.edu/~fvalilai Recommended prerequisite Manufacturing process I (21-418) Class time Sunday-Tuesday 18:00-19:30 Course evaluation Mid-term (25%) Final exam (40%) Quiz (5%) Exercise (Manufacturing Lab.) (30%) Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 2

Session reference Reference: Edward B., “Integrated product and process design and development : the product realization process”, CRC Press, 2010 John Priest, Jose Sanchez;“Product Development and Design for Manufacturing: A Collaborative Approach to Producibility and Reliability, Second Edition”, CRC Press, 2001 Mital et al. ,“Product Development A Structured Approach to Consumer Product Development, Design, and Manufacture”, Butterworth-Heinemann, 2008 Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 3

Course Description (Continued..)
Contents: Product development in the changing Global world Stages of Product Development The Structure of the Product Design Process Early design: Requirement definition and conceptual Design Trade-off analyses: Optimization using cost and utility Metrics Detailed design: Analysis and Modeling Design Review: Designing to Ensure Quality Production System; Strategies, planning, and methodologies Production System Development Planning and Preparation for Efficient Development Supply chain: Logistics, packaging, supply chain, and the environment Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 4

Design Review: Designing to Ensure Quality
Designing for Assembly and Disassembly in manyd ifferent and conflicting types of information. It is important to recognize that the customers, themselves, may not be able to tell you completely what they want. The customer may not understand the implications of new technology breakthroughs or innovative ideas. There are several approaches for knowledge acquisition of customer needs. The design team shouldu se several of these methods to insure that the final requirements are representative of the customer. Methods for capturing and documenting customer needsin cludes: Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 5

Designing for Assembly and Disassembly A consumer product often is an assemblage of several individual components. Each component has been planned, designed, and manufactured separately. Only after they are assembled into the final product can they effectively perform their intended function Assembly of a product is a function of design parameters that are both Intensive (material properties) and extensive (physical attributes) in nature such design parameters includes shape, size, material compatibility, flexibility, and thermal conductivity A consumer product often is an assemblage of several individual components. Each component has been planned, designed, and manufactured separately. However, by themselves, there is very little use to component parts. Only after they are assembled into the fi nal product can they effectively perform their intended function Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 6

Designing for Assembly and Disassembly In an engineering context, disassembly is the organized process of taking apart a systematically assembled product (assembly of components). Products may be disassembled to enable maintenance, enhance serviceability and/or to affect end of life objectives, such as product reuse, remanufacture, and recycling In an engineering context, disassembly is the organized process of taking apart a systematically assembled product (assembly of components). Products may be disassembled to enable maintenance, enhance serviceability and/or to affect end of life objectives, such as product reuse, remanufacture, and recycling Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 7

Designing for Assembly and Disassembly Design for assembly Design for assembly (DFA) seeks to simplify the product so that the cost of assembly is reduced. Consequently, applications of DFA principles to product design usually result in improved quality and reliability and a reduction in production equipment and part inventory DFA, in principle, recognizes the need to analyze the design of both the part and the whole product for any assembly problems early in the process to cut costs during the entire product cycle. Design for assembly (DFA) seeks to simplify the product so that the cost of assembly is reduced. Consequently, applications of DFA principles to product design usually result in improved quality and reliability and a reduction in production equipment and part inventory. It has been repeatedly observed that these secondary benefi ts often outweigh the cost reductions in assembly. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 8

Designing for Assembly and Disassembly Design for assembly Different Methods of Assembly Manual assembly Manual assembly is a process characterized by operations performed manually, with or without the aid of simple, general-purpose tools, such as screw drivers and pliers The cost per unit is constant, and the process requires little initial investment Although this is the most flexible and adaptable assembly method, there usually is an upper limit to the production volume, and labor costs (including benefits, workers compensation due to fatigue and injury, and overhead for maintaining a clean and healthy environment) are higher The different methods of assembly are as follows: • Manual assembly: Manual assembly is a process characterized by operations performed manually, with or without the aid of simple, general-purpose tools, such as screw drivers and pliers. The cost per unit is constant, and the process requires little initial investment. Manual assembly involves parts that are transferred to workbenches, where the assembly of individual components into the fi nal product takes place. Hand tools generally are used to aid the worker for easy assembly. Although this is the most fl exible and adaptable assembly method, there usually is an upper limit to the production volume, and labor costs (including benefi ts, workers compensation due to fatigue and injury, and overhead for maintaining a clean and healthy environment) are higher. • Automatic assembly: Often referred to as fi xed automation, this method uses either synchronous indexing machines and part feeders or nonsynchronous machines, where parts are handled by a free transfer device. The system generally is built for a single product and the cost per unit decreases with increasing volume of production. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 9

Designing for Assembly and Disassembly Design for assembly Different Methods of Assembly Automatic assembly Often referred to as fixed automation, this method uses either synchronous indexing machines and part feeders or nonsynchronous machines The system generally is built for a single product and the cost per unit decreases with increasing volume of production The different methods of assembly are as follows: • Manual assembly: Manual assembly is a process characterized by operations performed manually, with or without the aid of simple, general-purpose tools, such as screw drivers and pliers. The cost per unit is constant, and the process requires little initial investment. Manual assembly involves parts that are transferred to workbenches, where the assembly of individual components into the fi nal product takes place. Hand tools generally are used to aid the worker for easy assembly. Although this is the most fl exible and adaptable assembly method, there usually is an upper limit to the production volume, and labor costs (including benefi ts, workers compensation due to fatigue and injury, and overhead for maintaining a clean and healthy environment) are higher. • Automatic assembly: Often referred to as fi xed automation, this method uses either synchronous indexing machines and part feeders or nonsynchronous machines, where parts are handled by a free transfer device. The system generally is built for a single product and the cost per unit decreases with increasing volume of production. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 10

Designing for Assembly and Disassembly Design for assembly Different Methods of Assembly Fixed or hard automation Fixed or hard automation characteristically involves a custom built machine that assembles only one specific product and entails a large capital investment. As production volume increases, the fraction of the capital investment compared to the total manufacturing cost decreases. Indexing tables, parts feeders, and automatic controls typify this inherently rigid assembly method. typify ˈtɪpɪfʌɪ/ verb 1. be characteristic or a representative example of. "tough, low-lying vegetation typifies this arctic area" synonyms:epitomize, exemplify, be representative of, represent, be characteristic of, characterize; More 2. represent; symbolize. "the sun typified the Greeks, and the moon the Persians" synonyms:symbolize, be symbolic of, represent, stand for, be emblematic of;rareemblematize Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 11

Designing for Assembly and Disassembly Design for assembly Different Methods of Assembly Robotic assembly This form of assembly is best suited for those products whose production volume lies between the manual and automatic assembly methods. This method of product assembly is the most flexible and can achieve volumes closer to the automatic assembly methods. Soft automation or robotic assembly incorporates the use of robotic assembly systems. Although this type of assembly method can have large capital costs, its flexibility often helps offset the expense across many different products. typify ˈtɪpɪfʌɪ/ verb 1. be characteristic or a representative example of. "tough, low-lying vegetation typifies this arctic area" synonyms:epitomize, exemplify, be representative of, represent, be characteristic of, characterize; More 2. represent; symbolize. "the sun typified the Greeks, and the moon the Persians" synonyms:symbolize, be symbolic of, represent, stand for, be emblematic of;rareemblematize Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 12

Designing for Assembly and Disassembly Design for assembly Different Methods of Assembly The different methods of assembly are as follows: • Manual assembly: Manual assembly is a process characterized by operations performed manually, with or without the aid of simple, general-purpose tools, such as screw drivers and pliers. The cost per unit is constant, and the process requires little initial investment. Manual assembly involves parts that are transferred to workbenches, where the assembly of individual components into the fi nal product takes place. Hand tools generally are used to aid the worker for easy assembly. Although this is the most fl exible and adaptable assembly method, there usually is an upper limit to the production volume, and labor costs (including benefi ts, workers compensation due to fatigue and injury, and overhead for maintaining a clean and healthy environment) are higher. • Automatic assembly: Often referred to as fi xed automation, this method uses either synchronous indexing machines and part feeders or nonsynchronous machines, where parts are handled by a free transfer device. The system generally is built for a single product and the cost per unit decreases with increasing volume of production. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 13

Designing for Assembly and Disassembly Design guidelines for different modes of assembly Manual Assembly Eliminate the need for decision making by the worker, including making final adjustments Eliminate excess parts and combine two or more parts into one, if functionally possible Avoid or minimize the need to reorient the part during the assembly process Minimize the total number of individual parts, if possible. To facilitate this objective, multipurpose components may be used. Ensure good product accessibility as well as visibility. • Eliminate the need for assembly tools or special gauges by designing individual components to be self self-aligning and self self-locating. Parts that snap and fi t together eliminate the need for separate fasteners. This results in speedy as well as more economical assembly • Minimize the total number of individual parts, if possible. To facilitate this objective, multipurpose components may be used. • Eliminate excess parts and combine two or more parts into one, if functionally possible. • Avoid or minimize the need to reorient the part during the assembly process. Ensure that all insertion processes are simple. Avoid the need for rotation, releasing, and regripping. Vertical insertion always is preferable, since it utilizes gravity to accomplish the task. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 14

Designing for Assembly and Disassembly Design guidelines for different modes of assembly Automatic Assembly Self-aligning and self-locating features need to be incorporated into the design to facilitate assembly. As with all other Design For X principles, use a high percentage of standard parts Avoid the possibility of parts tangling, nesting, or shingling during feeding Avoid flexible, fragile, and abrasive parts Self-aligning and self-locating features need to be incorporated into the design to facilitate assembly. Considerable improvement can be achieved by using chamfers, guide pins, dimples, and cone and oval screws. • Use the largest, most rigid part of the assembly as a base or fi xture, where other parts are stack assembled vertically to take advantage of gravity. This, in turn, eliminates the need to use an assembly fi xture. The best assembly operation is performed in a layered fashion. If this is not possible, the assembly should be divided into subassemblies and plugged together at a later stage. • As with all other Design For X principles, use a high percentage of standard parts. Employing the concept of group technology, begin with fasteners and washers. Use standard tangle1 ˈtaŋɡ(ə)l/ verb gerund or present participle: tangling 1. twist together into a confused mass. "the broom somehow got tangled up in my long skirt“ synonyms:entangle, snarl, catch, entwine, intertwine, intertwist, twist, ravel, knot,enmesh, coil, mat, jumble, muddle More shingle2 ˈʃɪŋɡ(ə)l/ gerund or present participle: shingling roof or clad with shingles. modules and subassemblies. • Avoid the possibility of parts tangling, nesting, or shingling during feeding, since this can complicate and unduly delay the assembly process. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 15

Designing for Assembly and Disassembly Design guidelines for different modes of assembly Automatic Assembly Self-aligning and self-locating features need to be incorporated into the design to facilitate assembly. Considerable improvement can be achieved by using chamfers, guide pins, dimples, and cone and oval screws. • Use the largest, most rigid part of the assembly as a base or fi xture, where other parts are stack assembled vertically to take advantage of gravity. This, in turn, eliminates the need to use an assembly fi xture. The best assembly operation is performed in a layered fashion. If this is not possible, the assembly should be divided into subassemblies and plugged together at a later stage. • As with all other Design For X principles, use a high percentage of standard parts. Employing the concept of group technology, begin with fasteners and washers. Use standard tangle1 ˈtaŋɡ(ə)l/ verb gerund or present participle: tangling 1. twist together into a confused mass. "the broom somehow got tangled up in my long skirt“ synonyms:entangle, snarl, catch, entwine, intertwine, intertwist, twist, ravel, knot,enmesh, coil, mat, jumble, muddle More shingle2 ˈʃɪŋɡ(ə)l/ gerund or present participle: shingling roof or clad with shingles. modules and subassemblies. • Avoid the possibility of parts tangling, nesting, or shingling during feeding, since this can complicate and unduly delay the assembly process. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 16

Designing for Assembly and Disassembly Design guidelines for different modes of assembly Self-aligning and self-locating features need to be incorporated into the design to facilitate assembly. Considerable improvement can be achieved by using chamfers, guide pins, dimples, and cone and oval screws. • Use the largest, most rigid part of the assembly as a base or fi xture, where other parts are stack assembled vertically to take advantage of gravity. This, in turn, eliminates the need to use an assembly fi xture. The best assembly operation is performed in a layered fashion. If this is not possible, the assembly should be divided into subassemblies and plugged together at a later stage. • As with all other Design For X principles, use a high percentage of standard parts. Employing the concept of group technology, begin with fasteners and washers. Use standard tangle1 ˈtaŋɡ(ə)l/ verb gerund or present participle: tangling 1. twist together into a confused mass. "the broom somehow got tangled up in my long skirt“ synonyms:entangle, snarl, catch, entwine, intertwine, intertwist, twist, ravel, knot,enmesh, coil, mat, jumble, muddle More shingle2 ˈʃɪŋɡ(ə)l/ gerund or present participle: shingling roof or clad with shingles. modules and subassemblies. • Avoid the possibility of parts tangling, nesting, or shingling during feeding, since this can complicate and unduly delay the assembly process. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 17

Designing for Assembly and Disassembly Evaluating design for assembly Several methods for assembly evaluation exist, such as The Hitachi assembly evaluation method. The Lucas DFA method. The Fujitsu productivity evaluation system. The Boothroyd Dewhurst DFA method. The AT&T DFA method. The Sony DFA method. SAPPHIRE (a software package used to analyze ease of product assembly). Various researchers have proposed methods for evaluating the effi ciency of a product design from the perspective of product assembly. Comparison of two different product designs using one of these methodologies can enable one to ascertain the better design. As such, these methods concentrate on an objective design evaluation. Note that several methods for assembly evaluation exist, such as • The Hitachi assembly evaluation method. • The Lucas DFA method. • The Fujitsu productivity evaluation system. • The Boothroyd Dewhurst DFA method. • The AT&T DFA method. • The Sony DFA method. • SAPPHIRE (a software package used to analyze ease of product assembly). Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 21

Designing for Assembly and Disassembly Evaluating design for assembly The Hitachi assembly evaluation method. This method aims to facilitate design improvements by identifying weaknesses in the design at the earliest stage in the process by using an assemblability evaluation score and an assembly cost ratio Assemblability evaluation score ratio (E) assesses design quality by determining the difficulty of operations, Assembly cost ratio (K), which projects elements of assembly cost The objective of the Hitachi assemblability evaluation method (AEM) is to facilitate design improvements by identifying weaknesses in product design at the earliest possible stage. This is achieved using two principal indicators: An assemblability evaluation score ratio (E), which assesses design quality by determining the diffi culty of operations, and an assembly cost ratio (K), which projects elements of assembly cost. The Hitachi method considers both cost and quality important. This means that a low-cost design is not necessarily the best; alternatively, a good design may be too expensive. This is the only evaluation method that takes product design economics into account and hence is not purely technical in nature. Figure 7.3 illustrates the fl ow of logic in making design decisions using the Hitachi evaluation method. The following is Hitachi’s stepwise procedure for general design evaluation: • The general universe of assembly operations is categorized into 20 elemental assembly tasks. Each task is assigned a symbol indicating the task content. Each task relates specifi cally to insertion and fastening processes and not to parts handling. • Each of the elemental tasks is subject to a penalty score that refl ects the degree of diffi culty of the task. The penalty scores are obtained from analysis of shopfl oor data and are revised constantly to refl ect changes in technology and methods. The penalty scores then are ranked, and all are compared to the elemental task with the lowest penalty score. For instance, the simple task of placing an object on top of another object without requiring much accuracy is assigned a penalty score of 0 due to the inherent ease with which the task can be performed. Conversely, the more complicated task of soldering (assembly method) is assigned the much higher penalty score of 20. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 22

Designing for Assembly and Disassembly Evaluating design for assembly The Lucas DFA method. The Lucas method is based on a point scale that gives a relative measure of the difficulty associated with assembly. This method is based on three separate and sequential analyses, which are described by means of the assembly sequence flowchart The functional analysis  design efficiency (DE) >=60% Feeding/handling ratio =2.5 Fitting ratio =1.5 cost of manufacturing each component The Lucas DFA method was developed in the early 1980s by the Lucas Corporation in the United Kingdom. The Lucas method is based on a point scale that gives a relative measure of the diffi - culty associated with assembly. This method is based on three separate and sequential analyses, which are described by means of the assembly sequence fl owchart. Figure 7.4 depicts the Lucas design for mechanical assembly procedure Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 23

Designing for Assembly and Disassembly Evaluating design for assembly The Lucas DFA method. The functional analysis forms the fi rst part of this evaluation system. Components are divided into two groups. The fi rst group includes components that perform a primary function, therefore existing for fundamental reasons. These components are considered essential, or A, parts. The second group, B, components are nonessentials, such as fasteners and locators. The design effi - ciency (DE) is computed using the formula: DE = A/(A + B) × 100 The target effi ciency is at least 60% Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 24

Designing for Assembly and Disassembly Evaluating design for assembly The Lucas DFA method. concerned with the problems associated with handling components and subassemblies before they are admitted to the assembly system. By answering a group of questions regarding the size, weight, handling diffi culties, and orientation of a part, its feeding/handling index can be calculated. The feeding/handling ratio is computed as follows: F/H ratio = (Feeding/handling index)/Number of essential components The target value is 2.5. The fi tting analysis is similar to the feeding analysis. A fi tting index of 1.5 is a goal value for each assembly. However, note that there usually is greater variance in the fi tting indices than in the feeding indices. Again, an overall fi tting ration of 2.5 is desired. Fitting ratio = (Total fi tting index)/(Number of essential components) Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 25

Designing for Assembly and Disassembly Evaluating design for assembly The Boothroyd-Dewhurst method of assembly evaluation is based on two principles: The application of criteria to each part to determine if it should be separate from all other parts and The estimation of the handling and assembly costs for each part using the appropriate assembly process. The Boothroyd-Dewhurst method relies on an existing design, which is iteratively evaluated and improved. 1. Select an assembly method for each part. 2. Analyze the parts for the given assembly methods. 3. Refine the design in response to shortcomings identified by the analysis. 4. Refer back to step 2 until the analysis yields a satisfactory design. The Boothroyd-Dewhurst method of assembly evaluation is based on two principles: The application of criteria to each part to determine if it should be separate from all other parts and the estimation of the handling and assembly costs for each part using the appropriate assembly process. Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 26

Designing for Assembly and Disassembly Evaluating design for assembly The Boothroyd-Dewhurst method of assembly evaluation is based on two principles: The analysis generally is performed using a specific worksheet. Tables and charts are used to estimate the part handling and part insertion time Each table is based on a two-digit code, which in turn, is based on a part’s size, weight, and geometric characteristics The analysis generally is performed using a specifi c worksheet. Tables and charts are used to estimate the part handling and part insertion time. Each table is based on a two-digit code, which in turn, is based on a part’s size, weight, and geometric characteristics. Handling and insertion times are a function of the following component parameters. Each of these parameters directly affects the assembly process by simplifying or complicating it: Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 27

Designing for Assembly and Disassembly Evaluating design for assembly The Boothroyd-Dewhurst method of assembly evaluation is based on two principles: In column I, the number 1 is used to represent that a part is essential, and 0 to represent that a part is not essential. The method assumes that the ideal assembly time for a part is 3 seconds. Given that assumption, the design effi ciency can be calculated as (3 s × Nm)/Tm. It is clear from this discussion that the method can be quite time consuming, owing to the amount of intricate detail involved in the analysis procedure. A software package has been developed to accelerate the application of this process. Table 7.4 shows an example of estimated times required for manual handling of components for product assembly Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #16 28

Project Phase 7 Product DFA Analysis The first matrix to be used in QFD is known as the house of quality (HoQ). This matrix serves to describe the basic process underlying QFD: the transition (based on a strategy of input–output) from a list of customer requirements, the “what,” through to a list of considerations as to “how” the requirements will be met (product characteristics). Advanced Manufacturing Laboratory, Department of Industrial Engineering, Sharif University of Technology Product Planning & Development (21423), Session #5 29

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