Define the system architecture refers to how the assemblies and components are arranged and connected. The system architecture decision should take into account the constraints that apply to the product, such as size, weight, functionality, safety, cost, etc. 

A common mistake that beginner designers make is to create designs that have too many separate parts. This can lead to problems such as increased complexity, difficulty in manufacturing and assembly, higher cost, lower reliability, and more waste. A better approach is to try to design parts that are complex but elegant, meaning that they have multiple functions or features integrated into one piece. This can reduce the number of parts, simplify the assembly process, lower the cost, improve the performance, and enhance the aesthetics of the product.

For example, consider a bicycle frame. A novice designer might design a frame that consists of many tubes and joints that are welded or bolted together. This would result in a heavy, bulky, and weak frame that is hard to produce and maintain. A more experienced designer would design a frame that is made of fewer tubes that are shaped and curved to fit together smoothly and securely. This would result in a lighter, sleeker, and stronger frame that is easier to produce and maintain.

Modules

Modules are self-contained units that perform specific functions or provide a specific feature. Modules can be designed independently, tested separately, and integrated easily into larger systems. Modules can also be modified, replaced, or upgraded without affecting the rest of the system. This reduces the complexity, cost, and time of product development and maintenance.

An example of a modular product design, smartphone consists of several modules, such as the screen, camera, battery, processor, etc. These modules can be swapped or upgraded to improve the performance or functionality of the phone. This can also enable the development of product families, where similar modules are used to generate similar products with different features.

Here are some of the good reasons for chunking components into modules:

1. Enabling standardization: Standard modules can help reduce the number of different parts and interfaces in a product, which simplifies the design, manufacturing, and maintenance processes. For example, a modular power supply can be used for different electronic devices with different voltage and current requirements.
2. Precise geometric location requirements: Modules can help achieve precise alignment and positioning of components that are critical for the function or appearance of the product. Specifically, when one or more components needs to be precisely located with respect to another, it often is helpful to combine those parts into a single module.
3. Sharing of functions: Modules can help avoid duplication of components or assemblies that perform similar or multiple functions in a product. For example, a mechanism for moving product on a manufacturing line can be constructed as a single module to more precisely control movement and clamping.
4. When vendors are limited to specific capabilities or expertise: Modules can help outsource some parts of the product design or manufacturing to external vendors who have specialized skills or equipment. For example, a modular battery pack can be purchased from a vendor who has expertise in battery technology and safety. Power conversion modules like motors will have a different underlying expertise for development.
5. Similarity of the manufacturing or assembly process: Modules can help streamline the production process by grouping components that have similar fabrication or assembly methods. For example, a vehicle chassis can be made from the same material and process as other structural components of a car.
6. Localization of future changes: Modules can help reduce the impact of design changes or updates on the rest of the product by isolating the affected components in one module. For example, a display screen can be upgraded to a higher resolution or size without affecting the other parts of a device.
7. Enabling variety or customization: Modules can help increase the diversity and flexibility of the product by allowing different combinations or configurations of components to suit different user needs or preferences. For example, a furniture system can be assembled into different shapes and sizes according to the available space and style.