The last step in your product is done by making the documentation: technical drawing, part list and general drawing. But before this is done, the designing of the product has to be completed.
The construction is highly dependent on your product, there isn’t really a blueprint for it to follow. But after going through the previous steps, the product is almost completely defined.
Now every detail needs to be declared and documented with drawings, parts lists and manufacturing instructions. To help with this there exist rules, principles and guidelines that assist with this process.
The Basic Rules of Embodiment Design
The final design phase will finish the development of the product. At the end it has to be completely defined. For this process, the engineer has helpful principles, guidelines and the 3 basic rules: simple, unambiguous, reliable.
- "Unambiguous" The use of the product has to be clear and uncomplicated (fulfilment of the technical function).
- "Simple" There are no unnecessary functions or shapes other than for fulfilling the main function (economic realisation).
- "Reliable" The product is usable in a myriad of conditions without harming the user or environment (safety for both humans and the environment).
Principles of Embodiment Design
The following principles are applicable to many devices, but not every principle can be applied to every device.
Principle of division of Tasks
A division of tasks makes the system overall more efficient. It is easier to calculate the abilities, do repairs, it is cheaper, simpler and thus delivers higher utilization levels.
Principle of Self-help
The system uses the external effect to increase its abilities, or has an effect to cancel it out.
Self-reinforcing
Under normal load, the design ensures that main or auxiliary factors provide a reinforcing overall effect.
Self-compensating
Under normal load, the design ensures that an auxiliary factor counteracts the original effect and therefore provides compensation to achieve a greater overall effect.
Self-Protecting
The load on the device increases its load bearing capability. The faster a motorcycle drives, the harder it is to topple it. the door of a submarine is harder to open under water, because the water pressure pushes against it.
Principle of Force and Energy Transmission
Transmission, bending and compression in all parts should be controlled. The resulting deformation has to be calculated.
Flow of Force
The concept of flow of force is a visual concept for the transmission of forces, without physical validity. Parallel flow lines reach from the action to the reaction side: loaded point to the foundation for example. The concept shows that sharp corners, sudden changes and narrow diameters should be avoided.
Principle of Equal Strength
The strength of the part should be equally distributed, if the budget allows it.
Principle of Minimum Force Transmission Path
The path of the force should be as short as possible. The forces should restrict the stress to tension and compression.
Principle of Harmonised Deformation
If the device deforms under load, the mechanism has to adjust automatically accordingly. As someone steps into a bus, the suspension adjusts automatically.
Principle of Force Compensation
Existing forces in a system have to be compensated. For some forces a simple design adjustment is needed to strengthen the frame. For high forces, a symmetrical arrangement can be used to cancel two forces out against each other.
Safety and Reliability Principles
Safety measures can be separated into internal and external, where the internal give the highest safety. The external on the other hand are mainly warn or indicate danger.
Safe-Life Principle
Here the machine has to keep operating as long as possible. This is highly important for helicopters and planes, that can't stop but have to be shut down at a specific place and time (while standing still at the airport for example).
Fail-Safe Principle
To ensure the safety, the machine proceeds to fail operating. This effect can be seen with a table saw which is suddenly stopped by a break which disables the rotation of the saw.
Principle of Multiple or Redundant Arrangement
Multiple functions can fail and each can stop the operation. This is mostly used for machines where people can come into danger: multiple stop buttons in a machining shop, in elevators or engine in a car.
Indirect Safety
Safety is guaranteed by warning or shiling a dangerous device. A protective system or device, which is overseeing the function may shut down the system.
Example: Light sensor, overpressure vent, signs, protective covers, isolation.
Conclusion
The rules and principles can help to get an overview over all things to do. There should be several principles applicable to every product that show what should be done.
to be continued
Did you already read…
Part I: What does an Engineer do?
Part II: The first STEP on the way to YOUR Product: Inventing
Part III: The Other Kind of Research: Put your IDEA into the World
Part IV: The Requirement List: The ENGINEERS way of TAKING AIM
Part V: Function Analysis: No Maths but still solving Problems
Part VI: Part Solutions: Solving one function after another
Part VII: Combined Solutions or How to build a spaceship
Part VIII: Comparing Combined Solutions: What is the best spaceship?