Difference between Cartesian, Six-Axis, and SCARA Robots | Robotic solutions in delhi

Originally, the robots only automated manufacturing lines outputting high volumes. Now, the robots execute tasks in smaller-scale applications, because implementing them is easier than ever. Here is how Cartesian robots compare with the other two robot types. We solve different problems in the robotics industry by applying our science-based teams intellectual capabilities as we are a part of Robotic solutions in Delhi. Applying our experience in a wide spectrum of methods including Servo planetary, Strainwave gearbox, Six axis collaborative, Pic & place gantry robots etc. Robotic solutions in delhi

 

In contrast, the SCARAs and six-axis robots typically mount on a pedestal. SCARAs move in X, Y, and Z planes like Cartesians, but incorporate a theta axis at the end of the Z plane to rotate the end-of-arm tooling. This makes SCARAs good for vertical assembly operations, such as inserting pins in the holes without binding. However, the arm is essentially a lever, and that limits the SCARAs’ reach: The joints are load points that need robust bearings and high-torque motors to handle the loads when the arm extends.

 

Six-axis robots move forward and back, up and down and can yaw, pitch, and roll to offer more directional control than the SCARAs. This is suitable for the complex movements that simulate a human arm — reaching under something to grab a part and place it on a conveyor, for example: The additional range of movement also lets the six-axis robots service a larger volume than SCARAs can. Six-axis robots often execute welding, palletizing, and the machine tending. Programming their movements in 3D is complex, so the software typically maps the motion to a set of world coordinates in which the origin sits on the pedestal’s first joint axis.

 

To pick a robot, first you have to evaluate the application’s needs. That starts with profiling the job’s load, orientation, speed, travel, precision, and environment and the duty cycle, sometimes called LOSTPED parameters.

 

Load. A robot’s load capacity (defined by the manufacturer) must exceed the total weight of payload, including any tooling, at the end of the robot arm. What limits SCARA and six-axis robots is that they support loads on the extended arms. Consider a machining center that makes the bearing assemblies of 100 kg or more. That payload exceeds the capabilities of all but the largest SCARA’s or the six-axis robots. In a contrast, a typical Cartesian robot can pick and place such loads with ease, because its support frame and bearings consistently support the entire range of motion.

 

This Cartesian robot is just as reliable as SCARAs and articulating robots, which have set the parameters and directions of movement. In contrast, Cartesian robots are reconfigurable so manufacturers do not have to buy new equipment when designs change.

 

Orientation: It depends on how the robot is mounted and how it situates the parts or products being moved. The goal is to match the robot’s footprint to the work area. If a SCARA or six-axis robot’s floor or line-mounted pedestal creates obstruction, then such robots may not be the best option. If the application only needs movement in a few axes, then the small-frame Cartesian robots can mount overhead and out of the way. But for the intricate part handling or work needing four or more axes of motion, a Cartesian robot’s framework can pose too many obstructions, and a small SCARA robot, sometimes requiring just 200 mm2 of space and four bolts on a pedestal may be more suitable.

 

This Cartesian robot has controls that let the operators safely enter the machine cage to teach it coordinates for picking and placing (sometimes just by pulling the end effector from point to point). That reduces the training time for operators and reduces the need for engineers to alter machines already running.

 

Speed and travel: Along with the load ratings, robot-manufacturer catalogs also list speed ratings. One key consideration when choosing the robots for pick-and-place applications is acceleration times over significant distances. The Cartesian robots can accelerate at 5 m/sec or more, rivaling the performance of SCARA and six-axis robots.

Cartesian robots also make sense when the applications involve long spans. That is because designers can quickly modify and extend Cartesian robots as needed with modules to 20-m long. Speed and distance are further customizable by the choice of belt, linear motor, or ball-screw actuator. In contrast, the articulating arms are typically predesigned for a given reach, such as 500 mm, for example.

 

Environment: The Two factors that dictate the best robot are the working envelope’s ambient environment and hazards in the space itself. A third consideration, whether a robot will go in a clean room, is generally not an issue because all the robot types are manufactured in clean-room versions.

 

The pedestals of SCARA and six-axis robots tend to be compact, which is handy with the limited floor space. But this may be irrelevant if the installers can mount the robot’s support frame overhead or on a wall. In contrast, for applications with mechanical interference, as when a robot must reach into the boxes to pull out parts, six-axis arms are usually most suitable. Six-axis robots typically cost more than Cartesians, but the expense is justified if there is no way to execute the application without complex motion sequences.