ELECTROMAGNETIC HOLDER

What is an electromagnetic holder?

The electromagnetic holder is also called holding magnets, holding solenoids, or magnetic lifters. It is a type of material handling device that works only for magnetic and ferromagnetic components. Magnetic and ferromagnetic components refer to materials (metals, alloys, compounds, etc.) that contain elements including iron, cobalt, nickel, magnetite, and some rare-earth elements such as gadolinium. Because these materials can respond to the attraction and repulsion force of magnets, they can be held and lifted by magnetic holders. Nonmagnetic materials (metals, plastics, woods, etc.) do not respond to magnetism, and hence cannot be handled by magnetic holders. Nonmagnetic metals include gold, silver, copper, brass, bronze, lead, aluminum, and tin, to name a few.

In the following paragraphs, we will discuss how the electromagnetic holder works, what it can do in actual applications, and what advantages/limitations this device possesses. Hopefully, this post can help you determine whether this material handling device is right for your application. Let’s read on.

How does the electromagnetic holder work?

The electromagnetic holder and other types of holding solenoids apply electromagnetism to get hold of magnetic workpieces. Since the workpiece reacts to the magnetic force, the electromagnetic holder clamps and releases the workpiece by creating the magnetic field. Inside the electromagnetic holder, there is a wire coiling around a core piece. When the electrical current passes through the wire, it magnetizes the core, which then turns into a magnet and attracts any nearby magnetic materials.

Some electromagnetic holding systems allow the adjustment of the magnetic force. Namely, it can increase the force to attract larger or heavier workpieces, or decrease the force to clamp lighter, thinner, and smaller ones. Yet, most electromagnetic holders only allow for the simple on and off switch to control the clamping force. Click here to see more of Guang Dar’s magnetic work-holding equipment.

Applications

The electromagnetic holder is an ideal work-holding and workpiece delivery solution when other types of gripping are not that applicable. For example, it can get hold of thin, delicate metal sheets without distorting them. It is also easy to maneuver large, wide sheet metals using multiple magnetic holders together. Guang Dar’s magnetic holders are designed specifically for automated press machines and robot arms. Let’s take a look at what the holders do in these fields of application.

Press machine

Press machines are effective for sheet metal forming processes, including bending, shearing, curving, etc. In conventional sheet metal forming shops, the feeding of raw materials is conducted manually. Operators feed the sheet metal into the machine and retrieve it when the process is done. In automated press machine production lines, the factory uses conveyor belts or electromagnetic holders and rails to transport the workpiece from station to station. Using such approaches saves the manpower for manual operations, improves efficiency, and elevates the overall productivity of the line.

Robot arm

Robot arms, or robotic arms, often have a claw mechanism to grab the workpiece and there are multiple axes to help the arm perform precision work handling procedures. The claw design makes it easy to get hold of three-dimensional workpieces (cubes, spheres, cylinders, etc.). However, the same design does not work that smoothly when handling flat, thin workpieces (films, chips, sheets, etc.). Two main gripping mechanisms designed for thin films and sheet materials are vacuum and magnetism. The magnetic gripper (also attraction gripper) replaces the claw with the electromagnetic holder to clamp the workpiece.

Pros and Cons

The essential advantage of using the electromagnetic holder is that such units offer extremely convenient clamp and release operations for the user. It is literally a matter of turning on and off to control the clamping force. The efficiency and effectiveness this mechanism provides are the reason why the magnetic gripper is so prevalent in industries that require a high level of precision and automation. The downfall, on the other hand, is that the magnetic holder does not allow for the adjustment of magnetic force. Instead, we can only select the holder with a certain level of clamping force for a particular job. Typically, the larger the size of the holder, the stronger the clamping force, and vice versa. Contact us right now so that we can help you decide what size of the holder is best for your application.