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large smt inductors moving in the reflow oven

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#61060

large smt inductors moving in the reflow oven | 6 February, 2010

I have some large ROHS SMT inductors that are moving during the reflow process. I have tried adding extra solder, gluing and doing both. I don't know what else to try, any suggestions?

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#61061

large smt inductors moving in the reflow oven | 7 February, 2010

Makes us wonder how well the connections on the component match with the pads on the board.

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#61063

large smt inductors moving in the reflow oven | 7 February, 2010

> Makes us wonder how well the connections on the > component match with the pads on the board.

The pads are actually larger than the leads on the part, but I think we may have figured it out. We believe the conveyor vibration is causing it. When we put it on the upper conveyor used for double sided PCBs there was no movement. only when we run it on the lower conveyor.

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Jack Yeung

#61189

large smt inductors moving in the reflow oven | 22 February, 2010

Since the inductor is electro-magnetic, that means the device is composite of coil and ferrite metal. The inductor inside the reflow oven meets with blower motors which close to the inductor and generate magnetic field. With such conditions, Lawrenz force (remember your high school physics, the Right-hand fingers rule, moving coil in magnetic field) imposes at the inductors which is floating on the molten solder. Solution: 1. Rotate the board in other orientation, 2. Dispense a tiny SMT glue to bond the inductor on PCB before entering oven 3. Place a magnetic shield to close the magent field - need do some experient

Good luck Jack Yeung

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#61192

large smt inductors moving in the reflow oven | 22 February, 2010

We did the firt 2 with no luck.

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reflow oven profiler

Reflow Oven