14
Approximate values
Cu40 (0.004”) 0.10mm Time 3.40 Amps 80
Cu60 (0.006”) 0.15mm Time 3.40 Amps 100
Cu80 (0.008”) 0.20mm Time 3.40 Amps 130
Cu10 (0.010”) 0.25mm Time 3.40 Amps 160
Cu12 (0.012”) 0.30mm Time 3.40 Amps 180
14
Pick up the ribbon in your right hand and lay the ribbon on top of the damaged track.
Making sure that the ribbon is lying flat, depress the Foot Pedal Switch slowly,
thereby lowering the Electrodes onto the ribbon and PCB track. At this stage, do not
exert further pressure on the Foot Pedal Switch but by viewing through the
Microscope, make any final adjustments to the ribbon. When the ribbon is perfectly
aligned to the PCB track and Electrodes, exert a steady pressure to the Foot Pedal
Switch and the weld will automatically be made. Release pressure on the Foot Pedal
Switch and return the Weld Head to its 'rest' position.
15
Move the PCB and welded ribbon to the left until the Electrodes are over the 'good'
track and the ribbon is bridging the o/c (break) in the track. Repeat instruction 13.
16
By using the scalpel (knife), carefully cut off the excess ribbon.
THE REPAIR IS NOT COMPLETE
17
If a weld was not satisfactory, making a slight increase in Amps would ensure a
permanent bond (weld) is make next time. An increase in Amps will break down
resistance caused by oxidisation, etc but should not be too excessive, otherwise the
ribbon will be damaged. PLEASE REMEMBER: A good weld is made by a perfect
combination of Amps and Time. If too much of either is used, damage will occur to
the ribbon, track or substrate and in extreme cases, all three!
18
Note the Time and Amps readings on the display that you used to achieve your
perfect weld. Also, note the track width, ribbon width and if the track was copper or
tin-lead plated. Further adjustments or complete re-settings can be made at a later
stage, if required, by repeating the above operation.
19
Repeat steps 6 to 16 using different size ribbons, tracks or track finishes and put the
figures into the
CIR-KIT WELD 450's
memory by selecting Programme Switch.
20
If reduced width tracks are to be repaired, follow procedures 11 to 16. If a length of
over 3/8" (10mm) is to be repaired, the ribbon should be secured in the centre by
applying a thin coat of adhesive between the track and substrate and the ribbon
welded at both ends.
21
Small short circuits can be removed by cutting with a Scalpel.
22
After the repairs have been made to a PCB, it can be processed in any of the following
ways:-
HOT AIR LEVELLED
TIN-LEAD PLATED AND IR OR OIL FUSED
