Developing a Design Specification
The purpose of the design specification is to state what a successful design looks like.
Specifications can be divided into two categories:
Constraints: These are elements of the design that cannot be changed. They are limitations or essential requirements for the design. Dimensions (Size), Cost, Material or Process are examples of constraints.
Considerations: These are elements of the design that must be thought about. The constraints might These often have multiple solutions and it is up to the designer to find the optimum solution.
In Criterion D of MYP and DP Design, you test your design to measure how well it matches your specifications. This is how you measure how successful the design is. It is important, therefore, that your specifications are measurable in some way. Being as clear as possible in each specification will be vey important.
Clear, well-defined, and relevant specifications are important because you will refer to your specifications throughout the design cycle. You will use the specifications to guide the development of your ideas, justify the selection of the final design and in the designing of tests and evaluation of your final design.
Performance Considerations
These are related to what the product must do and how it functions. For example:
The chair must support 20kg.
The portable laptop stand must be assembled in 30 seconds without special tools.
Environmental Considerations
These are related to the impact of the product on the environment. This could be how it is produced in a sustainable manner, or the amount and type of energy it uses. For example:
The chair must be produced from reclaimed wood.
The glue should be non-toxic
The device should use renewable solar energy
Aesthetic Considerations
These are related to how the product looks, feels, tastes, smells, etc. For example:
The phone cover should be white or light grey.
The cushion on the chair should feel soft to the touch.
Dimension Constraints
These are related to the size of product itself, or the ability of the product to accommodate a certain size. For example:
must fit a 15" Macbook Pro laptop
The cart must fit through a regular doorway and in an elevator
Material Constraints
These are related to the type or amount of material used. These constraints can also refer to certain qualities of the material. For example:
must use sustainably-source plywood
Must flexible and light plastic
must be laser cut from three or few sheets of 800mm x 400mm plywood
Ergonomic Considerations
These are related to how the product interacts with the human body, and are associate with the function of the product. For example:
coat zipper must be easy to pull
must allow the user to sit comfortably for long periods of time
Cost Constraints
These are related the costs required to produce the product. For mass production, there might be a minimum cost associated at which a product is financially viable. For example:
Must cost less than $3.50 per unit to manufacture
Manufacture (Production)
These are related to the product processes that are used. For example:
Manufactured using the laser cutter
Manufactured using an ABS filament 3D printer
Safety Considerations
These are related to the safety of the product and how it must be designed to limit harm or pain for user:
Design should have no sharp edges that could injure a user
Machine must have an emergency stop button and safety guards over moving parts.
Materials should be non-toxic to humans
Software and Hardware Constraints
These are related to any specific hardware or software required to produce a product. If designing a program or digital product, these constraints might refer to they type of device or software needed. For example:
Code must run in the IDLE Python programming environment
Must run on an Arduino Uno