Mechanical design may be considered the process of turning raw materials into useful forms. Mechanical design is usually one where dynamics are involved (motion), but may be a static part with dynamic forces, or less commonly simply static (stationary). Mechanics simply implies a mechanism that fulfills a purpose.
Mechanical design may be required to improve an existing process, or to create an entirely new one. It may be a component of automation in manufacturing, a new design of a gearbox, a refrigeration cycle, or a turbine for generating electricity.
Defining the Problem
The first step in the mechanical design process is to define the problem. Only with a clearly outlined brief on what problem the design process is intended to solve, can the engineer begin the process of developing a solution.
When defining the problem, it’s important to gain as much information as possible about the application of the component being designed.
Measurements and Data Gathering
Once the problem has been properly outlined, data is needed. In a simple case, this may be just a matter of taking dimensional and environmental measurements, in more complex cases data logging from tests of similar designs may be required. It is important to obtain all the variables associated with the applied forces so that calculations can be made accurately.
Consider Options and Draft a Basic Design
At this stage, a basic solution needs to be sketched, usually on paper, which is a starting point for working out forces in the design calculations and for material choices. If designing to a specification, discussion with the client may be required at this point to check the feasibility of the solution.
Using the basic design, all the applied forces need to be calculated. Depending on the end use, this may involve using an industry standard to determine accepted loads and safety factors for variable items such as weather, (wind loads, snow loads) or standard cyclic use under certain conditions for determining fatigue.
Sizing and Material Choices
When all the forces are known, the basic design is now solidified by sizing and material choices. The forces will determine, for example, the size of cross section needed for shafts and trusses based on the forces being carried and the strength of the material used. If the sizes are impractically large for the forces an item needs to carry, then a redesign will be needed or a stronger material used.
A full design can be drawn up now to indicate the exact design of the item. This will be completed in either 3D or 2D computer drafting depending on the complexity of the task.
The design engineer will determine how best to manufacture an item, considering whether it is a one-off or an item that requires mass production. A prototype will be manufactured first, to test the required item.
If the prototype shows any flaws, the engineer will need to review the fault and apply design changes to address the deficiency. Once changes are made the new design will be checked, drafted, manufactured, and tested again.
Only once successful testing of a prototype is complete, will the item be put into production. In some places prior to production, certification is needed, which proves compliance with any required design standards.
Mechanical Design Overview
Mechanical design is best achieved if a full brief is made of what is required. Clients are encouraged to work with engineers throughout the design process where required to achieve the best results.