Soldering a steel cover onto a nickel plated EMI filter

Objective

Soldering a nickel plated steel cover onto a nickel plated steel EMI filter housing without damaging the RF circuit

End Product

EMI filter housing

Equipment

Ambrell 2 kW induction heating system, equipped with a remote workhead containing two 1.2μF capacitors for a total of 2.4μF

An induction heating coil designed and developed specifically for this application.

Materials

2” x 2” (50.8mm) nickel plated steel cover, 2” x 2” (50.8mm) nickel plated steel box and lead-free solder and flux

Temperature

573 ºF (300 ºC)

Frequency

229 kHz

Testing

A single turn square helical coil is used to solder the cover to the filter box. Solder flux is applied to the filter box and two solder turns (preforms) are placed covering the perimeter of the cover. The assembly is positioned under the coil and power is applied for 7 seconds to solder the seam

Benefits

Induction heating provides:

• Hands-free heating that involves no operator skill for manufacturing

• Repeatable, non-contact clean heating

• Fast precise heating

• Good solder flow without over heating the box and damaging RF circuits.

• Even distribution of heating

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