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walker demagnetizers for every ac application

Conveyorized Demagnetizer

Even when residual fields are small, magnetization in a machine shop can cause problems with mechanical equipment. For example, ferrous grit attracted by magnetized tools and dies can cause excessive wear, and magnetized parts in assembly operations may hang up in feed chutes and magazines.

The only answer to such problems is demagnetization, which is accomplished by subjecting a magnetized part to a strong reversing magnetic field to disarrange the magnetic particles so that the required residual magnetic field is obtained.

Aperature Type Demagnetizer

Walker demagnetizers are designed to negate the effect of residual buildup with units matched to the size and material of the workpiece and engineered with control circuits that can effectively erase the residual fields. Walker has the only compensated units available that provide increasing field strength with increases in workpiece volume.

how to select the right walker demagnetizing equipment

Selecting the right Walker demagnetizing equipment for the application depends on the type of ferromagnetic material, the strength of the magnetic field, the size and shape of the piece, and the permissible level of residual magnetism.

Ferromagnetic materials are classified as either "hard" - difficult to magnetize and demagnetize - or "soft" - easily magnetized or demagnetized. Hard materials include alnico, cobalt, and tungsten steels. Soft materials are metals such as pure iron, nickel, silicon irons, and ferrites. Common structural materials such as stainless steel, carbon steel and chrome steel will be soft or hard depending on heat treatment and processing.

Plate Type Demagnetizer

The residual field desired depends on the application. Job specifications usually spell out allowable levels. In many cases, 10 to 20 gauss is acceptable; in others, such as bearings and electrical components, even very small intensities will cause problems.

The size and shape of the demagnetizer depends on the shape of the part, as well as the degree of demagnetization required. It's important that it be no larger than required to do the job. Demagnetizing a small part in a large aperture will call for many times more power than needed to do the same job with a smaller unit.

Small parts are sometimes demagnetized collectively by passing them through the demagnetizing field in a tray or tote pan. Care should be taken not to pile them on top of one another, since this can lead to inconsistent results.

After demagnetization, a Walker "Hall Effect" Gaussmeter should be used to check the results.

selection chart
Welded Parts	For large parts, use a flat plate demagnetizer for localized demagnetizing. For small parts, the aperture type may be more suitable.
Bearing Components or Assemblies	The flat plate or aperture type is recommended. Either type is often used with a conveyor.
Tool Room Uses	The flat plate type most often fits the purpose, and is commonly used to advantage with a conveyor on production lines.
Small Components after Grinding	Here again, the flat plate type is the best choice, possibly with a conveyor.
Bulk Packed Items	Packaged nails, screws, drills, etc., are easily handled by using a flat plate demagnetizer.