Apparatus and method for weld bonding

Apparatus for welding together a pair of conductors separated by a thermo-plastic insulation material comprising:

• a source of pressure;
• a pair of welding electrodes moveable relatively toward each other when pressure from said source is applied thereto, said electrodes having a first pre-selected level of pressure for urging said pair of conductors into electrical contact and a second pre-selected increased level of pressure for forging the portion of said pair of conductors between the electrodes;
• a power supply for supplying voltage at a first level of current through said electrodes and said pair of conductors during said first level of pressure for generating heat to soften said insulation material adjacent said electrodes and thereby effect penetration of said insulation between said electrodes and supplying voltage at a second higher level of current for welding together said pair of conductors at the location of said penetration;
• a first control means comprising a detecting means for detecting said penetration and providing a control signal responsive thereto and a timing means activated by said control signal for changing from said first level of current to said second level of current after a pre-selected time delay from said penetration;
• and
• a second control means for increasing the electrode pressure from said first pre-selected level to said second pre-selected increased level during at least a portion of said second higher level of current.