Product Announcement from MuShield Company, Inc. (The)
Typical manufacturing methods for magnetic shielding involve bending, forming, welding, cold working, and mechanical finishing. Bending and forming are mechanical operations which can work-harden and/or stress high permeability materials. Welding introduces oxygen to the material, and mechanical finishing and cold working can introduce carbon. Each of these factors contribute to the degradation of shielding performance of high permeability materials.
Imagine a sponge. Some sponges have big holes, some are more tightly structured, each absorbs liquid to the point of saturation. Magnetic shielding material reacts in much the same way. Depending upon its structure, magnetic shielding material absorbs magnetic interference to a point of saturation. As magnetic interference increases, so too should the permeability of the material.
When the shielding materials that MuShield uses are exposed to extremely high levels of heat (2100oF for 1-2 hours), the grain of the material grows, increasing the materials ability to absorb magnetic flux. In addition, the hydrogen atmosphere in the heat chamber produces a chemical reaction with the shielding material, removing impurities such as carbon and oxygen, thereby enhancing permeability.
Finally, rapid and controlled cooling of the part freezes the desired grain of the shield, yielding maximum permeability. MuShield engineers regulate the temperature and the time the parts are in the heat chamber with care as it is critical that the parts maintain their structural and dimensional integrity.
MuShield has a large heat treating capacity and is committed to investing in additional equipment to keep up with the demand for these services. Fast turn around of heat treated parts is critical to MuShield customers.