FORMULATING A DESIGN PROBLEM PART 2

Pengumuman – dari Puan Marina Sila download lab module untuk minggu depan dari portal  lab project management Hantar drawing in template (assignment minggu lepas) next week by lab session. (except student baru). Individual. 1 day late submission -50%. In the detail drawing: 1. title block 2. top, front, left, iso view(3 rd angle projection) 3. dimensions

Recap Objectives  the desired attributes of a design. Constraints  strict limits that a design must meet to be acceptable.

Objective Tree A graphical representation of the objectives for the product. The top-level objectives in an objective tree, which is presented as a node at the peak of the tree, is decomposed or broken down into sub-objectives that are at differing levels of importance or that include progressively more details, so that the tree reflects an hierarchical structure as it expands downward. Ordered lists of the desired attributes of a design. Sub-objective  tells how to realize the top objective

Safe ladder objectives 1.The ladder should be safe 1.1The ladder should be stable 1.1.1Stable on floors and smooth surfaces 1.1.2Stable on relatively level ground 1.2The ladder should be reasonably stiff 2.The ladder should be marketable 2.1The ladder should be useful 2.1.1The ladder should be useful indoors Useful to do electrical work Useful to do maintenance work 2.1.2The ladder should be useful outdoors 2.1.3The ladder should be of the right weight 2.2The ladder should be relatively inexpensive 2.3The ladder should be portable 2.3.1The ladder should be light in weight 2.3.2The ladder should be small when ready for transport 2.4The ladder should be durable

electrical maintenance small, transportable light in weight of right weight outdoors indoors on level ground on floors inexpensive portable durable useful stiff stable Safe SAFE LADDER Marketable Objective Tree for Safe Ladder electrical maintenance small, transportable light in weight of right weight outdoors indoors on level ground on floors inexpensive portable durable useful stiff stable Safe SAFE LADDER Marketable electrical maintenance small, transportable light in weight of right weight outdoors indoors on level ground on floors inexpensive portable durable useful stiff stable Safe SAFE LADDER Marketable

Pairwise Comparison Chart Helps to understand the relative importance of the objectives  comparing objectives. To identify the values of objectives or their importance relative to one another and to order them accordingly. Procedure: 1. compare every objectives with each of the remaining objectives individually 2. add cumulative or total scores for each one of the objectives.

ObjectivesCostPortabilityUsefulnessDurabilityScore Cost-0011 Portability1-113 Usefulness10-12 Durability objectives are compared. The entries in each box of the chart are determined as binary choices, i.e. every entry is either a 1 or a 0. The PCC for the ladder design shows that the objectives ranked in the order of decreasing value or importance is: portability  usefulness  cost  durability A pairwise comparison chart (PCC) for a ladder design

Quality Function Deployment What is quality? 1. (Time magazine (1989)) i.Works as it should ii.Lasts a long time iii.Easy to maintain 2. Garvin (1987) i.Performance ii.Features iii.Reliability iv.Durability v.Serviceability vi.Conformance to conventions/ standards vii.Aesthetics viii.Perceived quality/ reputation of manufacturer A quality product: i.made of quality parts, which are made by high-quality processes ii.Functions or performs as expected (reliable) iii.Lasts a long time (durable) iv.Easy to maintain (serviceable)

Quality Function Deployment (QFD) A technique for identifying customer requirements and matching them with engineering design and performance parameters. Comes from a Japanese phrase “ … the strategic arrangement (deployment) throughout all aspects of a product (functions) of appropriate characteristics (qualities) according to customer demands.” Useful tool for formulating design problems for products in situations where several competing products are already on the market.

QFD Table  a chart that explicitly depicts the key relationships between customer requirements, engineering (or product) requirements, and the characteristics of competing products. General arrangement (5 regions): 1.Customer requirements 2.Engineering requirements 3.Matrix of requirements relations 4.Competitive benchmarks 5.Engineering targets

Refer to notes on customer requirement Quantifiable aspects of the system that can contribute to satisfying Customer Requirements. Benchmarking - Comparing your design with that of competitors Indicates the relationship between an engineering requirement and a customer requirement by an ‘x’ mark in the appropriate cell in the matrix. Lists the units and the numerical values of the targets for each engineering requirement.

House of Quality-one variation of QFD

House of Quality (for Product Planning) Room 1: Customer Requirements Room 2: Customer Importance Weights Room 3: Engineering Characteristics Room 4: Correlation Ratings Matrix Room 5: Benchmark Satisfaction Ratings Room 6: Benchmark Performance Room 7: New Product Targets Room 8: Coupling Matrix

Exercise