Hello Madhur,
There is no special need of laptop to mechanical branch.
If you have to do career in design  ,in that case you should learn AUTOCAD,SOLIDWORK and need laptop.
It is better to have laptop for any project, research etc.
Considering your budget decide wheather to buy or not.
Thank you!!

Hello Madhur.

No, it not necessary that you should have laptop.There is no need of laptop to the mechanical students.

Thanks.