TurtleBot3 has two different models: Burger, Waffle and Waffle Pi. The following list shows their components. The big differences between two models are the Motor, the SBC(Single Board Computer) and the Sensors.
Core components of Turtlebot3 are the followings: Chassis, Motors, Wheels, OpenCR1.0, SBC Computer, Sensor and Battery. The chassis are Waffle Plates that holds other components. The Waffle Plate plays an important role as a chassis although its size is as small as your palm. Waffle plate is manufactured with injection mold method to lower the manufacturing cost. However, the CAD data of waffle plate for 3D printing is also available via Onshape. Turtlebot3 Burger is a Two-wheeled differential drive type platform, but it is customizable structurally and mechanically in many ways: Cars, Bikes, Trailers and so on.
The CAD data is released to the Onshape, which is a full-cloud 3D CAD editor. Get access through a web browser from your PC or from portable devices. OnShape allows drawing and assemblying parts with co-workers.