Cartesian robots are a specific type of industrial robot that move on three orthogonal (perpendicular) axes — X, Y, and Z. These three axes are at right angles to one another and perform coordinated motions through a single motion controller.
Cartesian robots operate on cartesian coordinates, which are rectilinear two- or three-dimensional coordinates. While these axes all limit the robot to straight line motion in several directions, it is common for the third axis to be a rotary axis (such as a tooling arm on a CNC router).
The Benefits of Using Cartesian Robots
Why do many industrial applications call for cartesian robots? Machine designers tend to implement them for several reasons:
- Their rigid structure and straight-line movement allow them to move heavy payloads.
- Multiple robots can be controlled with a single controller, eliminating the need for PLC solutions or IO between multiple controllers.
- They allow for long strokes of approximately 2 meters, allowing them to move heavy loads over long distances.
- Their movements and functions are highly accurate and repeatable.
- Their fast movement speed and acceleration reduce cycle times.
- Dual arms and the ability to set two units on the Z axis reduce installation space.
- Can be constructed using nearly any type of linear actuator in conjunction with any variety of drive mechanisms (including belt, ball or lead screw, pneumatic actuator, or linear motor).
The Best Applications for Cartesian Robots
Cartesian robots are both suitable and ideal for a large number of industrial automation applications. They are ideal for applications like:
- Pick and place
- Material handling
- Loading and unloading
- CNC machine tooling
- Packaging automation
- Palletizing and depalletizing
- Storing and retrieving
- Product placement
- Cutting, scribing and sorting
- Process-to-process transferring
- Dispensing agents
- Precision spot welding
- Part assembly
How Cartesian Robots Differ from Gantry Robots and SCARA Robots
Not all robots that operate on X-Y-Z axes are cartesian robots. Gantry robots, for example, incorporate two X axes into the configuration. Gantry robots have two X axes with a single Y axis spanning them. This configuration has two solid benefits over that of a cartesian robot:
- Longer strokes (can carry loads longer distances)
- The ability to carry heavier payloads
SCARA stands for selective compliance assembly (or articulated) robot arm. These 6-axis robots have a circular work envelope that offers more flexibility than a cartesian robot, and they move better on a horizontal plane. However, this circular work envelope ends up using much more space than the rectangular envelope of cartesian robots. Cartesian robots are also much more precise in their movements and provide better repeatability. They are also easier to program.
The ideal applications for each type of robot can be summed up as:
- Cartesian: Where speed and precision is needed, with controlled movements on a straight line. Ideal for limited space applications and those with heavy payloads.
- Gantry: Same as cartesian but can be used for applications with much larger payloads. They are overkill and can result in larger expenses if their payload can be handled by a cartesian robot.
- SCARA: Where flexibility in positioning is needed. They are also more ideal for underwater and harsh environments, as cartesian robots require special coverings.