Design / Rekabentuk What is a design……????? Webster’s dictionary To design is to fashion after a plan The essential fact.. To create something that has never been To design is to imagine, specify and create things that don’t exist, usually with the aim of bringing them into the world.

Who involve…. Engineer Figure out ways to provide things that are needed or wanted Basic needed cheaper, easier to use, comfort, reliable, high quality Can evaluate conformance of the product to the design requirements. Material engineer provide the expertise in the optimum material selection that will be used to construct or make product. Design / Rekabentuk

The design process Consist of the following steps Recognition of the need Definition of a problem Gathering information Conceptualization Evaluation Communication of the design Design Process

Recognition of need Input from operating or service or marketing representative Usually arise from dissatisfaction with the existing situation May be to reduces cost, increase reliability or performance or just change because the public has become bored with the product. Design Process

Definition of problem Involve analyzing and clearly stating the problem Critical step the true prob. is not always what it seems to be at first glance Require small part of the total time to create formal design Often over look Define problem as broad as possible Should involve writing down a formal problem statement Design Process

Which express as specifically as possible what the design intended to accomplish. Objectives and goals, definition of any special technical terms, constrains on the design, criteria that will be used to evaluate design. Design Process

Gathering of information To identify the needed pieces of information and find or developed that information The needed information is different form the find in text book or articles published in journal The information is often more specific and current and current information. Information can be supply by the supplier, discussion with experts ( corporate with R & D center ) and outside consultants may be helpful. Design / Rekabentuk

Conceptual design The objective is to generate possible solution, schemes or methods to solve the problem. To achieve these possible solution, the team should conduct unconstrained discussion to get the member express all possible solution. In this phase, all information and previous knowledge are put together in order that the proper decision can be made. The output should be two or three schemes that have the greatest chance of achieving the desire objective. Design Process

Embodiment design This stage will evaluate the two or three conceptual solution or scheme selected in greater detail. Make final choice The selection is done with considerable feedback to the conceptual design activity The output of this stage should be rough drawing Design Process

Detail design Consider all the large number of small but important details to make or fabricate the product or component. The quality of work must be good Otherwise will course a delays, high cost, failure occur. The output of this activity is a set of very detailed drawing and final specification including tolerance, precision, joining method, finishing… To produce the component or product. Design Process

Design activities Can be classified into analytical, creative and execution types. Analytical activities Establishment of proposed action and collection of the data Creative activities The analysis, synthesis and evaluation and development activities. Engineer expected to do Design Process

Execution activities. The designer, in conjunction with client and/or company management, must make a decision and communicate it by means of detailed drawing, specification and other method. Results of these activities are constantly matched with the requirements and constraints. Design Process

Materials selection It is a crucial that the materials selection should be a part in the decision process at each stage of design. Allows the designer to find out early in the process, if there any problem in the availability, cost or processability of material. Choice of material should start at the conceptual stage. Identify possible materials from very broad class of material. In embodiment stage, we look in greater details Final stage, final design is made based on the data of actual material to be used Design Process

Factors in material selection Property profile i.Mechanical factor The ability of material to withstand the types of stresses imposed on it. Strength, modulus, the fracture toughness, fatigue strength, creep. ii.Life of component factors. These factor related to the length of time, the material perform their intended function in the environment to which they are exposed. Design Process

Corrosion, oxidation, wear resistance and the fatigue or corrosion fatigue life properties in dynamic loading. Performance of material based on these properties is the hardest to predict during design stage. Processing profile i.Physical factors Size, shape and weight of material needed and the space available for the component. Size and shape of component might constraint the heat treating of the material. Design Process

Example : Large size component may not be provided as a whole piece and consideration may have to be given to joining smaller sub-components. Necessitate to make the sub-component that are transportable. The shape of the sub-component material will dictate whether a casting or wrought product will be required. Influence the performance of material, when stressed in different modes. Design Process

Geometry considerations 1.What is the relative size of the component ? 2.How complex is the shape ?Are there any uniform cross section ? Could the component be divided into several simpler shape that might be easier to manufacture? 3.How many dimensions must be specified ? 4.How precise must these dimensions be ? Are all precise ? How many are restrictive, and which ones ? 5.What are the surface finish requirements ? Must all surfaces be finished ? Which ones do not ? 6.How much can a dimension change by wear or corrosion and the part still function adequately ? Design Process

Weight of material has implication Initial cost during application Example : In transport industry, where lightweight structures save energy cost and increase profitability. At one time, bicycle frame were constructed from welded steel tubing, now have being change to aluminum alloy, titanium alloy, and various fiber- reinforced composite. Carbon fiber frame now weight only 1.14 kg! Design Process

ii.Processing and fabricability Related to the ability to form or shape the material. Casting very intricate shapes Deformation ductile metals and thermoplastic materials Ceramic materials usually shapes by slower sintering Composite spry forming and lay-up technique. Fabricability embraces the joining processes ( welding, soldering, brazing ), forming and machining process. Design Process

Manufacturing concerns 1.Has the design addressed the requirements that will facilitate ease of manufacture ? 2.How many of the component are to be produces ? At what rate 3.What is the desire level of quality compared to similar products on the market ? 4.What are the quality control and inspection requirements ? 5.What are the largest and small thickness ? 6.Have standard sizes and shapes been specified wherever possible ? Design Process

iii.Cost and availability If the materials are readily available, it matter whether orders are made in tonnages or in pounds or grams. Customer also pays a cost-penalty when orders are nonstandard items requiring special or are nonstocked items, due to very little demand form other customers. Prepare recommend alternatives materials, provided that they are feasible candidates for the specific use. Design Process

Environmental profile i.Codes, statutory Codes are sets of technical requirements that are imposed on the material or the component Usually sets by customer or based from those of technical organization Statutory related to local, state and federal regulation about the materials and processes used or the disposal of material. Leaded brasses and steel used for bolt and screws, has banned by the OSHA Toxic chemical or solvents used in cleaning and processing, cannot be disposed with the regular sewage. Design Process