Creative Concept Convergence Tools For Use In The Product Development Stage Of Dfm/A

NESS: Each criteria should be developed to the same level of abstractness ( or detail ) as every other criteria, in so far as possible. Although many engineers consider all the criteria in early concept evaluation to be “fuzzy” since they cannot quantify all of them, even the non quantifiable criteria should be at the same level of abstractness as the other criteria. The statement, “Does the processor cut celery?” is not at the same level of abstractness as “Does the processor cut vegetables?”. QUANTIFIABLE (QUALIFIABLE): * Where appropriate the criteria should be expressed in terms that can be quantified with some metric that is viewed appropriate for early P ge 221.3 product design. The question “Does the product have good assemblability?” is too vague for most engineers to evaluate. A more quantifiable question might be, “Does the product have a low number of subassemblies? * This fourth criteria has been added through DFM/A teaching at GMI. The PUGH selection process proceeds as follows: 4 1. List the product function criteria in short phrases in each row of the PUGH matrix. Typically 8-12 criteria are used at the product level including not only the functional criteria of the product , but also, aesthetic functions, manufacturability metrics, assemblability metrics, serviceability indexes, and disposal metrics should be employed where appropriate. 2. Each new product concept should be briefly described in each column of the matrix. Any number of concepts from 2 12 can be evaluated. 3. A product concept sketch should be developed at the same level of detail for each of the concept ideas to feed the visual side of the brain during the evaluation process. 4. A DATUM (REFERENCE POINT, BENCHMARK ) must be selected against which each concept will be compared for each criteria. In most DFM/A practice the Datum for the initial selection process is the original product design. 5. Each concept is compared to the Datum ONLY, one criteria at a time until that new concept has been evaluated for all the criteria. The team then evaluates the next concept for all the criteria in the rows of the matrix. It is important to compare the new concepts only to the datum not to each other. A simple GO/NO-GO evaluation is made using the following criteria: + (Plus) = this concept is clearly better than the datum S (Same) = this concept is about the same as the datum (Minus) = this concept is not as good as the datum 6. Only when all the concepts have been evaluated relative to the datum, should the concept ratings be tallied. The + is a + 1, the is a 1, and the S is a. The algebraic sum of the ratings for each concept should be entered in the row marked “Concept Rating”. 7. If a single concept does not appear to clear # 1 idea in step 6, change the datum to one of the stronger concepts identified in the first evaluation and perform the PUGH analysis again. This time you will be comparing each concept, criteria by criteria, to a the New Datum. ( The old datum, the original product concept should be removed completely from the matrix along with the potential concepts that rated below the original concept in the first PUGH selection analysis.) The PUGH concept selection matrix shown in Figure 1 is the evaluation of five concepts for a new hand operated food processor. In this selection matrix, concept #4 has emerged as the most favorable concept. IMPLEMENTATION OF TOOLS INTO DFM/A A COURSE: The various tools for concept generation and concept analysis are learned through active practicum sessions throughout the term. Explanations of the application of each tool, the procedures for applying the tool and the direction to be taken as a result of the tool are given in tool instruction booklets. The concept generation ( Divergent Thinking ) and concept selection P ge 221.4 ( Convergent Thinking ) tools are applied in a single 2 hour practicum workshop. In the practicum session four student teams of four students tackle a engineering problem confronting a local organization. The “warm-up” problem that is most often utilized is one that has many solutions, both logical and illogical, that can be contributed by all students. The problem statement is: “How can we prevent the beaver dams at Camp Holaka from flooding the campsites?” When they start on the Beaver Dam Problem, the teams have already participated in some exercises to stimulate their divergent thinking. Each student team generates ideas using Classical Group Brainstorming, and Forced Random Stimulation. Each team generates 25 40 ideas in a 20 25 minute period. The concept generation activity is usually halted at this time to permit the application of the compression and selection tools within the time period. Within each team the ideas range from the violent death and destruction solutions to the calm ecologically acceptable technical solutions. Table I illustrates the range of concepts developed by one team. The team is first asked to cull out 10 percent of the ideas that are just too wild, too dangerous, too violent or too deadly to apply in a camp situation. The team removes: C 4, TNT, Acid, Poison, Guns, Snipers and Sterilize beavers. The team now looks for the Hits that jump out at them as interesting, intriguing, and unusual. They isolate the following concepts: 11. retaining wall 8. Remove trees 12 locks 28. Remove food 15. stilts for campground 34. Scents of enemies 19. Sump pump 35. Shield trees 20. Hydro plant 22. Drainage ditches 37. sandbags 38. cut trees for dike 39. cement wall They clustered these into four themes: I Lowering Water Level ( 18, 19, 20, 22, ) II Eliminating food ( 8, 28, 34, 35, ) III Separating camp from water (12, 15, 37, 38, 39, ) In the interest of time the practicum facilitator provided each team with a set of criteria for evaluating their final concepts using the PUGH Concept Selection matrix. The criteria used for the beaver problem are: Costs less than $100 Requires little maintenance Can be installed by scouts maintains water for beavers The team evaluated their four potential concepts against the datum of the present method ( i.e. tearing down part of the dam each week ). The team selected drainage ditches as the best idea. In the process of selecting their final concept, the team made their drainage ditches invisible by placing them inside plastic pipe and burring these in mud along the pound and inside old trees in the bottom of the pond. P ge 221.5 SUCCESSES AND CHALLENGES: Engineering students in a DFM/A course have learned to break that engineering mind set and generate divergent ideas. They have successfully adapted to a culling method to remove the “violent” ideas. They have adopted the PUGH Concept Selection Method as a filtering tool for product concepts. However, they do not want to garner together ideas to locate an appropriate broader theme for final concept generation. The reason for a Hit & Highlighting process does not seem to be important to them. Two challenges remain in instilling the implementation of concept selection tools in the DFM/A process in today’s engineering students. First, the importance of slow focused convergence on a central theme must be instilled in the students. Secondly, the ability to generate reasonable criteria, other than the direct product functions, that are parallel, distinct, equally abstract, and quantifiable.