FRAME

The frame is like the backbone of multirotor. It provides you area to mount the accessories you want.
There are many types of frame available in the market, but the best one must be crash resistant, rigid, super design. I tried to start from scrap and go-up with some of leading brands in the market.

                          "The frame has four arms which are perpendicular to other"

    Let's start with Scrap

 

Aluminium Frame 

We can build-up frame from many materials listed below:-

1-Aluminium 7075

2-Balsa Wood

3-ABS, etc

4-Carbon Fibre

5-Plastic

Aluminium 7075 is the alloy used in Aerospace and Aeroplanes because it is lighter, rigid, can absorb shock too. But opt it only when you can do casting or machining on it to get desired dimensions. 

Balsa Wood is the most used raw material to manufacture the UAV, Models, AeroDesigns, etc. But don't go for bigger for bigger design with Balsa Wood.

ABS, PLA etc are 3D printing material, use wisely the right material as per your need because every material has its own property and there is a huge range of material for the 3D printer. To study more about them follow 3D Source and many more websites.

Carbon Fibre is the most reliable material. It is rigid, tough, can withstand shocks and the most advantageous feature is lightest in weight. 

You can customise the Balsa wood, ABS/PLA frame but can't do with 7075 and Carbon Fibre because they need machining that may cost nearly of a new frame.
Plastic is the most used material to manufacture the frame.