There are many possible applications for robots in the manufacturing process, with the most frequent uses being found in machine tending, assembly, quality inspection, packaging and palletizing applications. Robotic arms are capable of performing repetitive tasks accurately and without taking a break, outperforming human workers in terms of reliability and availability. A robotic arm gripper mechanism can replace many functions of the human hand.
End-effector grippers on a robotic arm
Let’s take a moment to review the pieces of a robotic arm. Much like a human arm, a robot arm has joints that mimic an elbow, wrist, and hand.
The ‘gripper’ corresponds to the human hand and is also known as a robot end-effector or manipulator. Robotics companies have produced an array of grippers to meet the needs of manufacturers, with magnetic robot grippers being among the most popular.
What is a magnetic gripper and how is it used?
A magnetic gripper offers a way to handle the smallest of workpieces. Magnetic grippers use a magnetized surface to grab metal items. This type of gripper doesn't usually incorporate fingers or jaws, instead relying on smooth magnetic surfaces for handling. Magnetic grippers are common in industries where sheet metal and automotive parts are being moved along an assembly line.
While other types of manipulators rely on compressed air or hydraulics to generate movement and hold the piece, magnetic grippers do not. Instead, magnetic grippers use either electromagnets, which require DC power or permanent magnets, which are always on and do not require power to operate.
Although magnetic arm grippers can handle a wide range of potential applications, there are pros and cons to this type of industrial gripper.
Pros and cons of using magnetic grippers
As with any tech solution, there are benefits and drawbacks to choosing a magnetic robot gripper. First, let’s examine the benefits. This type of manipulator usually offers one surface to grab an object. This mitigates the issue of having robotic fingers that are too large or uniform to handle small and/or irregularly shaped pieces. It also has a fast grasping speed. Electromagnets can be turned on or off in an instant, enabling easy grasping and dislodging. This type of gripper also requires minimal maintenance, making it aflexible and cost-effective choice for manufacturers. Unlike vacuum grippers, a magnetic robot gripper can hold parts with holes or unusual grooves. It’s also important to note that this type of end-effector is typically low-maintenance.
One of the potential drawbacks of magnetic grippers for manufacturing applications is that pieces can be easy to dislodge, causing parts to slip out of the gripper’s grasp.
Depending on the strength of the magnetic grip, even small collisions with nearby workers or objects could cause the workpiece to fall from the flat surface. Additionally, even small amounts of oil on the surface of the gripper reduce the gripper’s ability to hold objects.
Further, pieces can remain magnetized after being handled by a magnetic arm gripper, with the result that even if you manage to pull the gripper away, the newly magnetized piece may attach itself to another piece of metal. Another limitation of magnetic grippers is that they can only handle ferromagnetic materials.
Integrating UR+ solutions
At Universal Robots, we design collaborative robots (or ‘cobots’) that are highly adaptable to your specific manufacturing and business needs. Alongside our cobots, we created UR+ --the industry’s largest ecosystem of peripherals and Application Kits. UR+ is designed to meet your automation requirements by supplying all the UR+ certified hardware and software you need to get started on your UR cobot application quickly and cost effectively.
For example, SMC’s MHM Magnetic Gripper Kit is a system that’s ideally suited to applications that involve handling ferromagnetic workpieces, especially those with irregular surfaces.
