CONFORMAL COATING AND STAKING (BONDING)
GENERAL REQUIREMENTS
staking and conformal coating
GENERAL REQUIRMENTS

Reliable staking and conformal coating results from proper design, control of equipment, materials, work environments and careful workmanship by trained and certified personnel.

The staking and conformal coating materials shall have dielectric prperties that will meet the minimum circuit requirments in all antcipated environments. The amterials shall be compatible, noncorrosive and curable under conditions that will not change or adversely affect the performance or reliability of the parts on the PWA.

adhesive bonding conformal coating

PREFERRED

ADHESIVE BONDING/STAKING

Adhesive bonding/staking material has been applied to the parts and locations specified by the approved engineering specification. Material quantity is sufficient to provide required support, but does not negate stress relief or mechanically compromise hardware reliability.

PREFERRED

CONFORMAL COATING

Coating covers all areas as specified on the engineering documentation. coating exhibits uniform color, thickness, proper adhesion, is smooth and tack free. No bubbles, entrapped contaminants or particles, excessive fillets, runs, drips, etc.

glass bodied parts component bonding

PREFERRED

GLASS-BODIED PARTS

Glass encased parts (i.e. diodes, etc.) shall be covered with transparent, resilient sleeving or other approved material, prior to staking or conformal coating with a rigid material.

NASA-STD-8739.1 [9.2.3.c], [11.6.3.e]
NASA-STD-8739.3 [8.1.4]

PREFERRED

3.5 GM PER LEAD/7 GM TOTAL RULE

Components weighing 7 grams (0.25 oz.) total, or 3.5 grams (0.12 oz.) per lead, shall be bonded to the mounting surface, in at least four evenly spaced places around component, when no other mechanical support is used.

Best Workmanship Practice

NASA WORKMANSHIP STANDARDS
NASA logo Released:
04.05.2002
Revision:
Revision Date:
Book:
8
Section:
8.01
Page:
1




CONFORMAL COATING AND STAKING (BONDING)
GENERAL REQUIREMENTS (cont.)
tantalum capacitors uninsulated metallic cased component

PREFERRED

TANTALUM CAPACITORS

All axial-leaded solid-slug tantalum capacitors shall be staked.

NASA-STD-8739.1 [9.2.4], [11.6.3.d]

PREFERRED

UNINSULATED METALLIC-CASED
COMPONENT

Metallic-cased components mounted over printed conductors or which are in close proximity to uncommon conductove surfaces shall be separated by insulation of suitable thickness.

NASA-STD-8739.3 [8.1.2.b]

adjustable components bridging in the underfill

UNACCEPTABLE

ADJUSTABLE COMPONENTS

The adjustable portion of adjustable components (i.e. potentiometers, variable capacitors, etc.), as well as electrical and mating surfaces shall be left uncoated.

Best Workmanship Practice

UNACCEPTABLE

BRIDGING/UNDERFILL

Conformal coating and/or staking materials shall not be allowed to bridge between the bottom of ceramic-bodied DIPs, flatpacks or surface mounted parts and the PWB.

NASA-STD-8739.1 [9.2.1], [11.6.3.b]

conformal coating used as staking

UNACCEPTABLE

CONFORMAL COAT USED AS STAKING

Conformal coating shall not be used as a staking material. Components should be properly staked prior to being conformally coated.

Best Workmanship Practice

NASA WORKMANSHIP STANDARDS
NASA logo Released:
04.05.2002
Revision:
Revision Date:
Book:
8
Section:
8.01
Page:
2





Click here for printable .pdf file for Section 801 Conformal Coating and Staking (Bonding) General Requirements click here to download Adobe Reader Click here to email the author of the Pictorial Reference Handbook
Need a printed copy?
(May take a while to load.)

Requires Adobe Reader.
Need Adobe Reader?
Click here to download.
Questions? Suggestions?