🤖 SCARA vs. 6-axis robot with Vision system: How to choose the ideal combination?

🔹 Introduction: Flexibility vs. Speed

A robotic arm in manufacturing is either a fast sprinter or a flexible acrobat. The choice between a SCARA robot and a 6-axis robot (or cobot) depends purely on the application. But the arm itself is worthless until we give it "eyes". A vision system is the key to smart automation because it allows the robot to adapt to the real world, where parts are never perfectly aligned.

🔹 SCARA robot: The king of speed and simplicity

SCARA (Selective Compliance Assembly Robot Arm) is a four-axis robot that, thanks to its design, is the fastest manipulation arm for surface work.

Construction and principle: It moves in two axes in the horizontal plane (X, Y) and vertically in the Z axis. Thanks to the absence of complex joints, it has extremely high rigidity and speed, comparable to a Delta robot.

Uses: It is ideal for high-speed Pick and Place, surface mounting of parts (e.g. PCBs) or simple assembly tasks.

Limitations: It does not have the ability to rotate or change the angle of the arm outside the vertical axis. It cannot weld, operate CNC or load parts at an angle.

🔹 6-axis robot (Cobot): Flexibility and agility

On the other hand, a 6-axis robot (whether a traditional industrial or collaborative cobot) is the most flexible.

Design and principle: It has six joints, which allows it to reach almost any angle and position, similar to a human hand. This allows it to work behind obstacles or manipulate parts in difficult spaces.

Uses: It is universal. Ideal for welding, operating CNC machines, quality control (the robot rotates the camera) and complex assembly where it is necessary to insert the part at an angle.

Limitations: It is more complex in design and slower than SCARA.

🔹 Vision system: Eyes for the robot

Vision system (camera system) is a technology that gives the robot intelligence and flexibility.

Why a vision system? The robot must know where the part is and how it is oriented. The vision system eliminates the need for expensive positioning fixtures. The robot adapts to the fact that the part is positioned differently on the conveyor each time.

Types of vision:

• 2D Vision: Ideal for flat parts (DPS, caps, labels). The robot detects the position and rotation of the part in the X and Y planes.
• 3D Vision: Necessary for Bin Picking (picking chaotically filled parts from a crate) or for checking depth and flatness.

Selection by task:

• SCARA + 2D Vision: For high-speed electronics assembly or stamping where parts move on a belt.
• 6-axis Cobot + 3D Vision: For CNC operation where it is necessary to grab the part, rotate it, and place it in the fixture at an angle, or for bin picking.

🔹 Conclusion: The connection between the shoulder and the eye

A SCARA robot arm is ideal for fast, repetitive and simple tasks on a surface. A 6-axis robot (cobot) is necessary for complex tasks where dexterity is needed. In both cases, however, the key to modern and flexible automation is a vision system that frees the robot from dependence on a perfectly aligned part.

Need to find out whether a SCARA sprinter or a 6-axis acrobat is more suitable for your assembly? Visit svet-robotu.cz and discuss with us the ideal combination of arm and vision system for your application.