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  • Removing glued SMDs

    From HW@21:1/5 to All on Wed Jan 29 11:41:20 2025
    On some boards, the SMD components are glued down prior to wave
    soldering.

    What is the best method for removing these parts, preferably without
    damage?

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  • From legg@21:1/5 to none@no.no on Wed Jan 29 07:29:57 2025
    On Wed, 29 Jan 2025 11:41:20 +0100, HW <none@no.no> wrote:

    On some boards, the SMD components are glued down prior to wave
    soldering.

    What is the best method for removing these parts, preferably without
    damage?

    Unaware of one.

    Remove to replace only.

    RL

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  • From Roger Hayter@21:1/5 to legg on Wed Jan 29 12:39:08 2025
    On 29 Jan 2025 at 12:29:57 GMT, "legg" <legg@nospam.magma.ca> wrote:

    On Wed, 29 Jan 2025 11:41:20 +0100, HW <none@no.no> wrote:

    On some boards, the SMD components are glued down prior to wave
    soldering.

    What is the best method for removing these parts, preferably without
    damage?

    Unaware of one.

    Remove to replace only.

    RL

    Expensive or proprietory chips are regularly removed from donor boards with a mixture of hot air, flux and perhaps LMP solder, for reuse. But I agree no one is going to reuse a resistor or capacitor.

    --

    Roger Hayter

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  • From Crash Gordon@21:1/5 to All on Wed Jan 29 11:12:59 2025
    On 1/29/2025 4:41 AM, HW wrote:
    On some boards, the SMD components are glued down prior to wave
    soldering.

    What is the best method for removing these parts, preferably without
    damage?

    Most of the adhesives used for this soften at solder-melting
    temperatures, so the parts can be fairly easily removed with hot air.

    For large components, or less heat-sensitive underfill materials (I'm
    looking at you, Apple...) some scavengers have had success using a mill
    to grind away the PCB (for scavenging the part from a scrap board) or
    the part itself (for removing a failed part to replace it). Obviously,
    it's important to get the PCB exactly level to the milling plane, and
    precise depth control is critical.

    --
    I'm part of the vast libertarian conspiracy to take over the world and
    leave everyone alone.

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  • From legg@21:1/5 to Roger Hayter on Thu Jan 30 08:29:47 2025
    On 29 Jan 2025 12:39:08 GMT, Roger Hayter <roger@hayter.org> wrote:

    On 29 Jan 2025 at 12:29:57 GMT, "legg" <legg@nospam.magma.ca> wrote:

    On Wed, 29 Jan 2025 11:41:20 +0100, HW <none@no.no> wrote:

    On some boards, the SMD components are glued down prior to wave
    soldering.

    What is the best method for removing these parts, preferably without
    damage?

    Unaware of one.

    Remove to replace only.

    RL

    Expensive or proprietory chips are regularly removed from donor boards with a >mixture of hot air, flux and perhaps LMP solder, for reuse. But I agree no one >is going to reuse a resistor or capacitor.

    Epoxy dhesive is used on wave-solderable SMD assemblies, to
    prevent parts being swept away in the wave process, or in
    subsequent reapplication of reflow processes.

    There is a body size, pinspacing limitation that prevents
    most complex/costly parts from this manufacturing technique.
    Consult your part vendor if in doubt.

    The epoxy adhesive used, once cured, will not be degraded
    at a later time by temperatures provided by hot air and bonds
    stronger than most IC packaging material fracture stress limits.

    RL

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