Permanent lifting magnets are powerful magnetic devices that can load and unload burn tables and, when properly installed and operated, provide greater safety than many other mechanical material handling devices.
Permanent lifting magnets are ideal for carrying semi-finished products such as machined parts, castings, press molds, steel plates, bars, and tubes. They can also add safety and efficiency to cutting table operations.
Permanent magnet systems require fewer operators and helpers than other material handling solutions. They lift and transfer iron and steel parts without slings, hooks, or cables – and without marring the product’s surface. There is no requirement for an outside power source, thus no concern for dropping parts due to a power outage.
Using permanent lifting magnets reduces workplace hazards because the staff is less inclined to break safety protocols by climbing or walking on burn tables during loading and unloading tasks. More labor-intensive loading/unloading procedures bring greater risks of injury from tripping hazards and repetitive motions.
There are a variety of key factors to consider when selecting a permanent lifting magnet. Dimensions, weight, shape, material thickness, temperature, surface condition and contact area of the item to be lifted must all be evaluated at the start of the selection process.
Material thickness is especially important as thinner steel does not allow full magnetic saturation, thus lower holding force. Derate values are model specific and can usually be found in product literature. The increased flexibility of thinner materials often requires multiple evenly spaced magnets on a spreader beam or magnets with large contact surfaces to maintain flatness and prevent peeling away from the magnet face.
Material temperature is important as the permanent magnet field strength is reduced as temperatures increase. As the magnet cools back down, it will typically return to full strength at room temperature. However, if rare earth magnets reach temperatures of 175 degrees F or higher, that loss of strength will likely be permanent.