For choosing the right lifting magnet model five other factors to consider that affect the lifting force other than the weight of the load:
The contact surface
If a distance (air gap) exists between the lifting magnet and the load to be lifted, the magnetic flux is made more difficult and thus reduces the lifting capacity. Rust, paint, dirt, paper or rough machined surface can have such an air gap result and in turn mean a reduction in the lifting force.
The material thickness
The magnetic flux of the lifting magnets requires a minimum material thickness. If the workpiece does not reach this minimum thickness, the lifting force is smaller. For larger lifting benefits greater material thicknesses are required.
The workpiece dimensions / intrinsic stability
If the length or width of the load is larger, the workpiece sags and is formed between the lifting magnet and the load - especially at low material thicknesses - an air gap. This reduces the lifting force of the lifting magnets.
The composition of the load to be lifted
Steel with low carbon content is a good magnetic conductor eg F1110 or St37. Steel alloy with a high carbon content or with other materials such as steel loses its magnetic properties so that the power of the lifting magnets is low. Heat treatments which affect the steel structure also reduce the lifting power. The harder a steel the worse its response to magnets, and it tends to retain a residual magnetism. The nominal power of our lifting magnets is valid for a steel with low carbon content, such as C 40 / St37 .
The temperature of the load to be lifted
The higher the temperature the faster the molecules vibrate the steel. Quick vibrating molecules provide the magnetic flux higher resistance. Our data apply to max. 80 °C.
In almost the same way, the factors making 1,2,4,5 also noticeable in the magnetic clamping.
Selection Guide for Lifting magnets under Criterion air gap/surface finish
Selection Guide for Lifting magnets under Criterion material thickness