| 摘要 |
If the workpieces involved are steel plates, they can form part of a magnetic circuit through which flows a closed magnetic current. Where a break occurs in the circuit, e.g. in the form of a seam gap, a magnetic leak flow occurs which causes a magnetic polarisation of the seam gap edges. These magnetic poles attract the ferromagnetic powder, causing it to be positioned in or in the immediate vicinity of the seam gap. The strength of the magnetic current can even be used to contribute to a small amt. of additive material being applied. Alternatively, the workpieces can be magnetised in advance, possibly in a separate appts., so that a magnetic polarisation of the seam gap edges is guaranteed. It is also possible for work equipment such as fixtures to form part of the magnetic circuit. |
