The robotic arm is one type of mechanical arm that replicates moments exactly according to the program in a three-dimensional space, this can be used in harsh conditions where humans cannot involve.

The robotic arm can be described as a chain of links that moved by joints. Based on the use end effector can be changed.
some of the end actuators are

Robotic arm 6 Degree Of Freedom 6 dof
Robotic arm 6 Degree Of Freedom

The above image is a 3D printed robotic arm 3d printed used industries with small moments in a harsh chemical environment.