WIRE PREPARATION
EXCIMER LASER ABLATIVE AND THERMAL STRIPPING
two conductors, one stripped, the other in the process of being stripped
EXCIMER LASER ABLATIVE (ELA) AND
THERMAL STRIPPING

Excimer laser ablative (ELA) stripping employs a laser to achieve extremely precise stripping of "difficult to strip" insulation materials and intricate conductor stripping geometries.

Thermal stripping is performed using a heated tool to melt a ring or groove into the insulation down to the conductor. The severed insulation section is then manually removed without damaging the conductor.

See Section 1.01 "Wire Preparation, General Requirements", for common accept/reject criteria.

insulation jacket neatly trimmed

PREFERRED

GENERAL REQUIREMENTS

The insulation jacket has been neatly trimmed, with no edge flash, smearing or damage. The conductor stranding lay (twist pattern) is undisturbed, and the conductor is undamaged.

ACCEPTABLE

THERMAL DISCOLORATION

Slight discoloration of the insulation jacket(s) at the trimmed edge is acceptable. Evidence of burning or charring is not acceptable.

NASA-STD-8739.3 [7.2.2]
NASA-STD-8739.4 [10.1.2], [19.6.1.a.1]

acceptable edge flash unacceptable edge flash and smearing

ACCEPTABLE

EDGE FLASH

Edge flash shall not exceed one-quarter insulated wire diameter (1/4 d.). Edge flash (as depicted) is considered normal, and should not contaminate or interfere with a crimped or soldered termination.

NASA-STD-8739.4 [10.1.6]

UNACCEPTABLE

EDGE FLASH/SMEARING

The edge flash is in excess of one-quarter insulated wire diameter (1/4 d.), and the stripped section exhibits smearing (melted insulation/film), which is considered a contaminant.

NASA-STD-8739.4 [10.1.6]

NASA WORKMANSHIP STANDARDS
NASA logo Released:
03.31.2000
Revision:
B
Revision Date:
07.03.2002
Book:
1
Section:
1.03
Page:
1




WIRE PREPARATION
EXCIMER LASER ABLATIVE AND THERMAL STRIPPING (cont.)
insulation jacket with scuffing damaged conductor insulation

ACCEPTABLE

SCUFFED INSULATION/JACKET

Slight scuffing (a dull or rubbed appearance) of the insulation surface finish is acceptable, provided no other damage is evident.

NASA-STD-8739.3 [7.2.2]
NASA-STD-8739.4 [10.1.2]

UNACCEPTABLE

DAMAGED INSULATION/JACKET

The conductor insulation and/or cable jacket shall not exhibit any damage, such as nicks, cuts or charring. Conductors/Jackets exhibiting damage (other than minor scuffing) shall not be used.

NASA-STD-8739.3 [13.6.2.a.1]
NASA-STD-8739.4 [19.6.2.a.2]

burned insulation jacket burned strands

UNACCEPTABLE

BURNED/CHARRED/PITTED INSULATION

Burned or charred insulation is the result of excessive heat application during the stripping process.

NASA-STD-8739.3 [6.6.1], [7.2.2], [13.6.2.a.1]
NASA-STD-8739.4 [6.6.1], [10.1.2], [19.6.2.a.1]

UNACCEPTABLE

BURNED/ETCHED STRANDS

Burned or etched strands are typically caused by current flow (leakage) between the thermal stripper blades, or as a result of stripping an energized conductor.

NASA-STD-8739.3 [6.6.2.b]
NASA-STD-8739.4 [19.6.2.a.2]













NASA WORKMANSHIP STANDARDS
NASA logo Released:
03.31.2000
Revision:
B
Revision Date:
07.03.2002
Book:
1
Section:
1.03
Page:
2


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