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Epoxy for holding large inductors

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#57768

Epoxy for holding large inductors | 14 January, 2009

I am attempting to identify a good epoxy to hold on larger parts on thru the reflow process for the opposite side. We currently dispense epoxy prior to second reflow on the corners of the component because the epoxy we use cures before reflow and doesn't allow the parts to settle to the board. Does anyone one have any recommendations on an epoxy we can dispense with our Camalot under the component on the first pass that will allow the part to settle to the board and be cured before the next lead reflow process.

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#57769

Epoxy for holding large inductors | 14 January, 2009

We use Loctite 3609 - it's good stuff.

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#57771

Epoxy for holding large inductors | 14 January, 2009

We currently use Epibond 7275 and it cures way too quickly to allow the component to settle down on the board. Have you used the Loctite 3609 in the application i'm speaking of with success?

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#57772

Epoxy for holding large inductors | 14 January, 2009

In BIG-boy, high vibration applications to secure large components, we've used 3M #2214 structural adhesive [One part, 250*F (121*C) curing 100% solids, paste consistency epoxy adhesives designed for bonding metals and many high temperature plastics such as fiberglass reinforced plastic, polyester, polysyphenylene sulfides and phenolics.] It's dispensable. Don't know if your component will settle to the board before curing.

Why not push the component into your current epoxy before it cures?

We have no relationship, nor receive benefit from the company referenced above.

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#57773

Epoxy for holding large inductors | 14 January, 2009

We love Loctite 3609 as a chip bonder, but would never consider it to secure large components

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#57774

Epoxy for holding large inductors | 14 January, 2009

Doesn't sound like we use it exactly like your application. Similar to what davef says we use it for smaller to medium size or dense parts (sigle dot under the center of the part) that have potential to fall off on 2nd side processing. I can say it does seem to cure/flow flat as I can't say we've had problems with leads not contacting pads due to addition of the stuff.

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#57776

Epoxy for holding large inductors | 14 January, 2009

We view both Epibond 7275 and Loctite 3609 to be very similar. They're competing chip bonders.

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#57783

Epoxy for holding large inductors | 15 January, 2009

After doing some more research it looks like Loctite made a material called Cornerbond 3515 that seems as if it has the characteristics we are looking for such as curing after the solder is liquidous. But it appears that it isn't manufactured anymore. If this material had the holding power to make sure a CDRH125NP-150MC doesn't during the second reflow it sounds perfect. Does anyone have suggestions comparable to the 3515?

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#57806

Epoxy for holding large inductors | 16 January, 2009

We've used our standard chipbonder- Heraeus PD944- for this type of application. While it does cure before reflow, when the part is placed onto the site, the material compresses and spreads and thus that potential standoff isn't an issue. We've also used a modified version of this process where we placed and reflowed side 1 as per normal then, before printing side 2, apply the PD944 to the part(s) on side 1 then invert and process as usual. The material cures before reflow and thus, the part is secured before the secondary reflow occurs. Unless cosmetics is important (and if it is, you need only be careful during application), you shouldn't have an issue. I imagine that some of the materials others have mentioned would act similarly though I have no personal experience with them. If you're nervous about it, get a solder sample and some parts and give it a go and see what happens. Good luck!

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