What is a SCARA Robot?

FANUC SR-6ia Scara Robot
The SCARA robot is one of the common types of industrial robots. SCARA robots were originally developed in 1978 and mainly used for assembly applications. The original meaning of the SCARA acronym was Selective Compliance Assembly Robot Arm. However, over the years SCARA robot technology has advanced and expanded to other applications outside of assembly. This led to a change in the definition of the SCARA acronym. Today it is defined as Selective Compliance Articulated Robot Arm.

SCARA robots are small industrial robots that are typically pedestal or floor mounted. Some SCARA robots can be wall mounted as is the case with SCARA’s from FANUC’s SR series. They generally have low payloads ranging between 0.5 kg to 20 kg. Their reaches tend to be shorter with most around 1,000 mm or less. The majority of SCARA robots are configured with four axes, giving them a lower range of motion than a six-axis robot. There are some SCARA robots with three axes, however, four is the standard. The FANUC SR-3ia is an example of a SCARA industrial robot.

The four-axis configuration of SCARA robots allows them to move along the X, Y, and Z planes. It also provides them with 360 degrees of rotational movement around the Z axis which allows for a cylindrical work envelope. The axes of SCARA robots feature a combination of dynamic and rigid movements. The X and Y axes of SCARA’s are flexible allowing for dynamic movements. This is where the “Selective Compliance” comes from in their name. Compliance refers to flexibility, but not all axes are flexible, so it is selective. The Z axis is the rigid axis since it is fixed.

The four-axis configuration of SCARA robots combined with their smaller footprint, makes them one of the fastest types of robots. With four axes there are fewer joints to control and move allowing for greater speeds than articulated and cartesian robot types. Delta robots still have an advantage over SCARA robots when it comes to speed.

While Delta robots may be faster, SCARA robots are considered more affordable when compared to all other robot types. They have the best price to performance ratio. With fewer axes and their smaller size, less components and materials are used to build SCARA robots helping to keep their cost down. Buying a used FANUC SR-6ia can be an even more affordable alternative to a new SCARA robot while still providing the same benefits.

As mentioned earlier, SCARA robots were originally developed for assembly automation, but since then have expanded to other applications. SCARA robots are still used today by many industries for the automation of assembly processes. The FANUC SR-12ia excels at high-speed assemblies. Their combination of dynamic and rigid axes allows them to easily automate assembly processes such as inserting bolts. Manufacturers in the electronics and bio-medical industries frequently use SCARA robots for assembly projects.

SCARA robots also excel at material handling processes such as pick and place and packaging. Other applications that can be automated by SCARA robots include 3D printing, inspection, palletizing, and dispensing.

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