Drone Fabrication

For people to comment you have to be more specific.
What is the maximum cost? Is 600 kg the total weight or will there be additional payload? If so, what is the all up weight?
Have a look at these links. May give some clues.
1. Computational multicopter design of drones
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2. Design of Drones for civil applications
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3. Build your own drone
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Just wondering how big a drone will have to be if it's to carry 600 Kg payload ☕

It is the weight lifting drone. It should carry at least 400 kg of weight. It is a multidisciplinary drone. I want to fabricate it for my Final Year Project. But I didn't know the motor specifications, Battery specifications, material specifications for blades as well as for drone body.

A drone designed for an all up weight of 1000 Kg with all weather capability is certainly not an end of term project. The cost will be huge, fabrication and testing a nightmare. In my opinion this calls for a major aerospace design team and large funds and time. Unlikely that any CEan can give you more than some references to the usual DIY projects..
What you are looking for is something like the Rustom UAV in terms of weight and payload.
<a href="https://en.wikipedia.org/wiki/DRDO_Rustom" target="_blank" rel="nofollow noopener noreferrer">Drdo Rustom</a>

This does not look like an end of term project.

A.V.RamaniA drone designed for an all up weight of 1000 Kg with all weather capability is certainly not an end of term project. The cost will be huge, fabrication and testing a nightmare. In my opinion, this calls for a major aerospace design team and large funds and time. Unlikely that any CEan can give you more than some references to the usual DIY projects.
What you are looking for is something like the Rustom UAV in terms of weight and payload.
<a href="https://en.wikipedia.org/wiki/DRDO_Rustom" target="_blank" rel="nofollow noopener noreferrer">Drdo Rustom</a>

This does not look like an end of term project.

Sir, What about if we fabricate drone using 3d printing which should weigh at least 10 kgs. It might be used as spy drone.

3D printing does not automatically imply low weight. If you want a payload of 400 kg, it is a big vehicle.
There are many available designs for something like 1 kg payloads. See here:
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A.V.Ramani3D printing does not automatically imply low weight. If you want a payload of 400 kg, it is a big vehicle.
There are many available designs for something like 1 kg payloads. See here:
#-Link-Snipped-#

Sir, what if I am going for payload of 8 to 10 kg

<a href="https://diydrones.com/profiles/blogs/huge-high-payload-hexacopter" target="_blank" rel="nofollow noopener noreferrer">diydrones.com</a>