A Brief Introduction to Engineering Design

Design is a vast subject which involves the visualization of one's perception for giving shape and size to an object perceived to be manufactured for a useful purpose. Design can be made for any object having physical existence. It may be a sticker, cloth, utensil, table, chair, fan, washing machine or anything that you can use in daily life. The fashion of modern days also requires for a design to be prepared prior being adopted by general public. Overall, we can say that every physical object that we can see around us has a design of itself. Moreover, the design is much more a representation of shape of an object in two dimensional or three dimensional space depending upon the preference of individual using graphics to represent his perception.

Design covers almost all the physically existing objects and a wide range of aspects. When we will get a little bit deeper in this subject, a new branch of design emerges out, which is known as engineering design. Engineering design involves the use of human experience, properties of matter, mathematical calculations and physical laws in addition to the concept of shape and size(refer the term design above) to make possibly the most efficient things useful for human beings.

Engineering design is one of the most important aspects of the life of modern human beings. Today, we can see complex shape buildings, highly durable bridges, airplanes, very fast moving cars and many more such creations of highly advanced human civilization just because of engineering design. Moreover, it has helped us to make things more efficient(i.e. using minimum energy and giving maximum output). Keeping in view the tremendous support of engineering design towards the advancement of our civilization it does not looks inappropriate to quote:

"The existence of human civilization on the planet Earth extensively depends on how efficiently we will develop and utilize our engineering design skills along with durable resources present for us".

Basically, the engineering design procedure comes into act for following two purposes :

1. New Design Development

2. Modification In Existing Design

1. New Design Development

The new design development is adopted for creating a new component or a complete physical assembly of objects such as a mobile phone,machine, automobile etc. This process is initiated by high end technology experts in their respective field of work. New design is developed while taking in count some specifically new features to be given by a brand for a product already available in market or to implement a recent advancement in the field of science & technology and a marketing strategy directed by manufacturing firm or the brand. This is very critical thing for a manufacturing firm as it requires deeper knowledge, costly workforce and intensive testing.

2. Modification in Existing Design

A manufacturing firm designs a new product and launch it in the market. After that the design of product is influenced because of following reasons :-

• Service related concern raised due to failure of any component at customer's end - Even after intensive testing and redesigning of the newly developed product under practical conditions, some glitches are left unresolved. These glitches comes into face at the customer's end and reported to the service team. The service team studies the problem and inform the design team about what changes are required to implemented in the product so that the concerned problem may not arise in future. The design team changes the design and after passing the successful testing, the modified design is implemented permanently in the product to be manufactured by production unit.
  
• Customer's feedback : The marketing section of a manufacturing firm keeps in touch with the customers buying their product. They consistently extracts from them the feedback about their product and periodically gets the design modified by the design team according to the customer's requirements.
• Cost saving : Sometimes, the manufacturing firm finds new type of material that is cheaper in cost than the existing material used to manufacture the product and efficient in output as much as the one in action. This material is implemented to save the cost of making the product. Also, the shape and size of product gets modified sometimes for cost saving.
• Government Norms and requirements : The government and law of a nation sometimes amends the norms and condition applicable to the use of a product consumed by their citizens. The engineering team has to change the design in order to abide by the new laws and norms applicable to their product so that the law could not become an obligation in the path of their product's sale.
• Better aesthetics : The aesthetic looks of a products like automobiles, furniture etc. marginally affects the sale. Therefore, the manufacturing firm keeps changing the design for better looks.
• More Efficiency : Using minimum energy and getting maximum energy is one of the primitive goals of the engineers and the design team regularly strives hard to achieve it.
  

The implementation of engineering design process is very critical task as the design engineers are responsible for all the merits and demerits of their designed physical component. Therefore, the reputation of any manufacturing firm depends drastically on their design engineering team and a strong technical knowledge as well as deep understanding of latest market trends are expected from them. Moreover, while implementing even a minute change in design, it is required to be thoroughly tested and verified for proper working in practical situations where the modified object will be used by consumers. It is tested by testing engineers with the collaboration of design team.

The change through engineering design for both the new development and existing design will occur through the same procedure as per the stages discussed below :

1. Need For Change - First of all the need for the change in design is analyzed. This is the first and very crucial stage of engineering design procedure. In case of field failure related issue of product, the problem arouse must be understood and discussed thoroughly so that a consolidated recovery action may be taken. For new design development, the expectations of the customer must be kept in mind along with available resources of the manufacturing firm for making a stable balance between production and demand by designing an easily manufacturable product.

Consider the example of new design development of the rotor of an electric fan. First of all the cost of the most selling rotor available in market is analyzed(Say it is $10) and studied as a standard to decide the cost of manufacturing of new rotor of fan. Here, we have come to finalize about what we need???

We need to manufacture the rotor of an electric fan which must cost below $10.

2. Planning - After the need for change by the commencement of an engineering design procedure is completely analyzed, the next step is to plan the implementation of change in the best possible way. A good planning is the base of each success, so planning for engineering change must be strictly accurate according to the requirements.

Now we shall come to planning stage for our rotor. We will plan the following things to design a new rotor :

• Which cheapest material will be most suitable for our rotor taking in count the durability of the product?
• How much amount of this material should be used to manufacture a single piece of rotor?

• The rotor with how many numbers of wings is successful in market eg. 4,5,6,8 or 10?

3. Act - The design engineer comes up with the best solution to achieve their goal in the planning stage. And now it is time to act. The action to make a change in design of a physically existing component is taken by using highly advanced Computer Added Design software such as Catia, Pro-E,NX and Autocad which are powered with three dimensional graphical modelling feature. Once they have reached on a conclusion regarding physical and material related parameters of all the components of the product, the drawings for all of them are released. The drawings are released with optimum tolerances for dimensions like length, breadth, height etc. so that the component could be manufactured accurately with available manufacturing facilities.

Illustration Continued........

Various designs of a plastic made fan rotor, having 6 wings are prepared and the one with most dynamic as well as autonomous design is selected for final manufacturing.

For designing the fan rotor, three sample designs of a fan rotor were prepared as shown in images given above. Here, the Option-3 seems to be fulfilling the eligibility criteria of being most autonomous and dynamic design, so the design team will go ahead with the design of fan rotor shown in Option-3 for their project.

4. Testing - The new development as well as a new change in existing design is firstly implemented to make a few sample pieces of the product called "Prototypes" and then tested by testing engineers to verify for the proper working of the product with new change in its design. The report of the tests is submitted to design engineer and analyzed for further requirement for any change, if any further change is required then the above mentioned process is repeated for modification. In case the change seems relevant according to the study report of testing engineers, the design is implemented and mass production of the newly designed or changed product starts on a large scale.

For testing of the newly designed rotor, it will be assembled in an incomplete structure of an electric fan(structure without rotor only) and the fan will be continuously used to blow air for an optimum duration of time(say 14 hours). After testing period, the testing engineers will prepare the performance report of rotor acknowledging following points :

• What is the air blowing rate of the rotor?
• Has the rotor been damaged or has traits to be damaged soon after continuously operating of 14 hours?

• Does It fits easily and firmly on rotating shaft of motor?

The rotor fulfilling above mentioned criteria as per standard parameters will be given accreditation for mass production by the Research and Development team. In case some glitches are left, the design process will be revised for further improvement.