(2) Printing requirements Printing orientation relative to longitudinal cable axis. Lettering orientation depends on the cable diameter and the printing method. Two printing methods exist : - multipulse complete code -multicharacter printing
_________3. Principle
The laser is oriented on a mask where the characters are hollowed out. Each character selected automatically is marked on the cable by removal of the external clear varnish.The cable is moving continuously.
A. Marking Pitch The cables shall be marked as follows: For cable length less than 2 m (6.56 ft.), marking is made every 75 mm (2.9527 in.) For cable length more than 2 m (6.56 ft.), marking is made every 75 mm (2.9527 in.) at each end over a length of 1 m (3.28 ft.) and every 380 mm (14.9606 in.) in the central part.
B. Quality Requirements
R _______CAUTION : MAKE SURE THAT YOU DO NOT CAUSE DAMAGE TO THE CABLE INSULATION
R DURING THE CABLE MARKING PROCEDURE.
R DAMAGE TO THE INSULATION CAN CAUSE DETERIORATION OF THE
R MECHANICAL AND ELECTRICAL CHARACTERISTICS OF THE CABLE.
R The marking must be legible. The contrast must be more than:
-80% for CO2 laser marking
-50% for UV laser marking
__________________4. Safety Precautions
The laser marking process produces unhealthy, irritant or toxic fumes which must be eliminated at their source. For optimum efficiency, an extraction system should be provided to direct the fumes towards an activated carbon filter, as PTFE decomposition between 200 deg.C (392.00 deg.F) and 400 deg.C
(752.00 deg.F) produces:
-
in rather large quantities:
TETRAFLUORETHYLENE (slightly toxic),
HYDROFLUORIC acid (highly toxic),
-
in small quantities at around 400 deg.C (752.00 deg.F):
20-25-61 Page 6
PERFLUOROISOBUTYLENE (highly toxic).
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_______________________________________________________
MARKING TOOL - HOT STAMPING - DESCRIPTION AND OPERATION
___________
1. Utilization
This tool is used to identify the following cables:
-E0261 CF
-E0262 DK
_____________________
2.
Stamp marking Machine (Ref. Fig. 001) In these machines, the marking unit which carries the type making up the required identification is set in an electrically heated mobile head. This reciprocating head strikes the cable through the ink ribbon. The cable is captive in a guide appropriate to the outer diameter of the insulation. Cable feed as well as stamping can be manual or automatic. With these machines, cables from gage 24 to gage 10 can be identified with different size characters. Several types of machine are available, some with an operating temperature as high as 425 deg.C (797.00 deg.F). By selecting the appropriate operating temperature, most cables can be marked, from the NYLON jacket cable requiring the lowest temperatures to the PTFE jacket cable requiring the highest temperatures. With appropriate guides and characters, these machines can also be used to mark bundle identification sleeves or plates (e.g.: E0050).
_____________
3.
Drum Machines (Ref. Fig. 002) Raised printing characters are set out on several disks making up a drum. At the center of the drum, a heating resistor heats the assembly to the required temperature. When the identification of the cable is formed on the drum, the drum is locked in position. The cable, placed in a guide adapted to its diameter, strikes the characters through the ink ribbon. These machines operate in automatic mode when numerically controlled (CONRAC) or in semi-automatic mode when manually controlled (CONRAC or TAB). Their maximum operating temperature (350 deg.C (662.00 deg.F)) enables the marking of TEFLON FEP jacket cables from gage 24 to 14.
____________
4.
Cable Guides (Ref. Fig. 003) Cable guides must be perfectly adapted to cable diameters. It must be possible for the cable to move freely, but with no play, in the groove which centers and maintains the cable while it is marked. Each cable guide has its own part number specific to a given cable outer diameter and to the manufacturer of the machine.
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Stamp Marking Machine
Figure 001
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Drum Marking Machine
Figure 002
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Cable Guides
Figure 003
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_________________
5.
Marking Principle The metal characters (on a stamp marking unit or a drum, depending on the type of machine) are heated to high temperature. An ink ribbon is placed between the characters and the cable. Ink is deposited onto the cable by the heated characters that strike the cable through the ribbon. Character penetration depth (controlled by pneumatic pressure or a mechanical stop) as well as the length of time the characters are in contact with the cable through the ribbon determine marking quality. The cables must not move when it is struck.
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