Gantry or Robot for Pick and Place

Does the orientation change?

If the part is picked flat and placed flat, a gantry can do it with three simple axes. If the part has to be rotated, tilted or approached from a changing angle, that is what an articulated arm is for.

Straight transfers of large flat blanks are the classic gantry application. Once the move involves reorienting the part in space, the gantry starts needing extra axes and the cost advantage goes away.

How big and how heavy is the part?

A gantry carries load between two supported rails, so span and payload scale reasonably well. A robot cantilevers everything from its base, so payload at full reach falls off quickly.

For a large sheet metal blank, a gantry is usually the stiffer and less expensive structure. For a small part moved close to the base, the robot is more compact and more flexible.

What does the floor space allow?

A gantry occupies the volume above the working area, which is often space that is otherwise wasted. It keeps the floor free underneath.

A robot needs a footprint on the floor plus a guarded working envelope around it. In a crowded plant, that envelope is frequently the constraint that decides the question.

How likely is the application to change?

A gantry is optimised for the move it was designed for. Changing that move usually means mechanical work.

A robot is reprogrammable within its envelope. If you expect the part or the sequence to change, that flexibility has real value and is worth paying for.

A practical way to decide

Write down the actual move: pick point, place point, orientation change, part mass, cycle time and available space. If the move is a straight transfer of a large flat part inside a fixed layout, start with a gantry.

If orientation changes, if the part family is varied, or if you expect the application to be reused for something else in three years, start with a robot. Either way, the tooling and part presentation will cost more than you expect, and that is true of both.