-
the connection must allow the assembly obtained (wire + end fitting + connected item) to meet the requirements given in the standards relevant to the various associated components.
-
the connection of a component (diode, resistor) to an end termination must be considered as connection of a nickel-plated copper alloy multistrand wire of same diameter.
Example : diameter 0.6 mm (0.0236 in.) : as 24 size diameter 0.8 mm (0.0314 in.) : as 22 size diameter 1 mm (0.0393 in.) : as 20 size
B. Tensile Strength (Ref. Fig. 001) The tensile strength of crimped connections for the various wires must be greater than the values given in table 1.
C. Geometrical Distortion of the End Fittings Geometrical distortion related to crimping must not hinder or lead to additional precautions in the use of the end fitting from the cavity. For lugs and removable contacts, the geometrical distortions must not hinder or prevent normal usage of the tools planned for the installation or the removal of the item from the cavity. For removable contacts, the concentricity defects shall be limited to :
-0.30 mm (0.0118 in.) max. for size 12 and 16 contacts,
-0.28 mm (0.0110 in.) max. for size 20 contacts and below. The increase in the crimping barrel diameter shall the limited to :
-0.15 mm (0.0059 in.) max. for size 12 and 16 contacts,
-0.05 mm (0.0019 in.) max. for size 20 contacts and below.
20-25-21 Page 1
Table 1 - Minimum Tensile Strength of Crimped
Connections (daN)
Figure 001
20-25-21 Page 2
D. Position of Wire Insulation after Crimping (Barrel Closed) and (Open Barrel) (Ref. Fig. 002, 003)
_________3. Procedure
A. Pre-crimping checks
(1)
Wire shall be correctly stripped ( Ref.Chapter. STRIPPING TOOL).
(2)
Check correct combination of cable, tool, terminal end or connector.
(a)
Crimping tool and locator shall be correctly selected (Ref. CRIMPING TOOLS tables).
(b)
Before use, every tool shall be checked for:
-Identification (tool serial No.) with its own particular history card. The tool used will not nave exceeded 1000 crimps on an interval of 12 months without being tested, unless otherwise stated,
-cleanliness of die faces,
-
freedom from damage,
-
freedom from corrosion,
-
freedom from wear. Tools in regular use shall be cleaned daily to avoid build up of dirt and plating on die faces. Care shall be taken not to damage the die faces.
B. Post-crimping checks
(1) All crimped joints shall conform with the following visual checks:
-Correctness of form and location of crimp,
-freedom from facture and rough or sharp edges,
-burrs are inherent in some forms of crimping, (These burrs should not be excessive to the extend that they cannot be removed without the use of a tool),
-
crimping indents away from inspection hole,
-
crimping indent correctly centered on the barrel,
-no damage caused on the attaching system, or to the female contact pressure system (removable contacts)
-acceptable geometrical distortion, correct die mark,
-wire visible through inspection hole, if applicable,
-
position of insulation after crimping,
(Ref. Fig. 002)
-
position of wire after crimping,
(Ref. Fig. 003)
20-25-21 Page 3
Position of Wire Insulation after Crimping (Barrel Closed)
Figure 002
20-25-21 Page 4
Position of Wire after Crimping (Open Barrel)
Figure 003
20-25-21 Page 5
-
no strands outside the crimping barrel (and/or extending out the inspection hole),
-
no cut strands,
-adequate insertion of conductor strands in barrel where it is possible to check without damaging conductor,
-absence of damage to the conductor.
____
NOTE : It is recommended that each crimp has a gentle manual pull applied in order to establish there is no movement of conductor within the crimp. Due consideration must however be given to the size of cable under inspection.
______________4. Periodic Tests
A. Test Intervals
-
Each new tool before use shall be submitted for gauging, where applicable, and specimen checks.
-
Each tool shall be submitted for gauging at 1000 and 2000 crimps and only if successful, returned for use. The checking at 3000 crimps shall be by gauging and specimen checks. This procedure shall be followed at subsequent 1000 crimp checks.
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