SURFACE MOUNT TECHNOLOGY (SMT)
ADHESIVE APPLICATION
adhesive application
SURFACE MOUNT TECHNOLOGY (SMT)
ADESIVE APPLICATION

Adhesives are frequently used to temporarily hold SMT components in position prior to soldering. Once the soldering operations are completed, the adhesive residue is removed during the cleaning process.

The application of adhesive should be controlled to ensure proper placement, amount and cure. Excess adhesive, improper placement, or incomplete cure can contaminate solder paste and solderable surfaces, interfere with proper component alignment and impact cleanability.

consistent deposition of adhesive adhesive on solder pads

PREFERRED

The deposition of adhesive is consistent, properly placed and repeatable. Dots are centered under the part body, equal distant between the land pattern areas.

NASA-STD-8739.2 [8.9], [8.10.2]

UNACCEPTABLE

ADHESIVE ON LEADS/SOLDER PADS

Adhesive deposits on part leads and/or solder pads interfere with proper placement, component retention and solderability.

NASA-STD-8739.2 [8.10.3]

voids in the adhesive excessive adhesive

UNACCEPTABLE

VOIDS

Bubbles and voids in the adhesive reduce the deposit's cross-section and retention properties.

NASA-STD-8739.2 [8.9], [8.10.1]

UNACCEPTABLE

EXCESSIVE ADHESIVE

Excessive adhesive interferes with proper placement, component retention and solderability.

NASA-STD-8739.2 [8.10.3]

NASA WORKMANSHIP STANDARDS
NASA logo Released:
06.27.2002
Revision:
Revision Date:
Book:
7
Section:
7.03
Page:
1




SURFACE MOUNT TECHNOLOGY
ADHESIVE APPLICATION(cont.)
insufficient adhesive insufficiently cured adhesive

UNACCEPTABLE

INSUFFICIENT ADHESIVE

Insufficient adhesive may result in lost and/or misaligned components and increased rework.

NASA-STD-8739.2 [6.15.1], [8.9]

UNACCEPTABLE

INSUFFICIENT CURE

Insufficiently cured adhesive may result in lost and/or misaligned components and increased rework.

NASA-STD-8739.2 [8.9]

lost components skipping of adhesives

UNACCEPTABLE

LOST COMPONENTS

Exidence of lost components indicates a process control problem (excessive/insufficient adhesive, insufficient cure, etc.).

NASA-STD-8739.2 [6.15.4]

UNACCEPTABLE

SKIPPING

Skipping is an indicator of a process control problem and may result in lost components and increased rework.

NASA-STD-8739.2 [8.9]

UNACCEPTABLE

STRINGING

Stringing is an indicator of a process control problem, is a contaminant and affects overall solderability.

NASA-STD-8739.2 [6.15.1]

NASA WORKMANSHIP STANDARDS
NASA logo Released:
06.27.2002
Revision:
Revision Date:
Book:
7
Section:
7.03
Page:
2





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