Automatic welder control system

A method of forming a resistance spot weld comprising:

• providing a spot welder having an electrode electrically coupled to a weld controller;
• supporting said electrode on the piston rod of a cylinder assembly having a cylinder housing, said electrode and said piston rod being displacable with respect to said cylinder housing;
• monitoring the relative displacement between said electrode and said cylinder housing using a transducer and creating a displacement signal responsive to relative displacement therebetween;
• determining whether proper part fit up is achieved prior to the initiation of welding by monitoring the displacement signal utilizing a microprocessor controlled monitor which is coupled to the weld controller;
• compensating for electrode wear prior to the initiation of welding by monitoring the displacement signal utilizing said microprocessor controlled monitor;
• initiating welding;
• varying weld duration by monitoring electrode displacement which occurs as a result of welding;
• identifying good and bad welds by monitoring electrode displacement which occurs as a result of welding;
• and
• determining weld expulsion by monitoring electrode displacement which occurs as a result of welding.

A method of forming a resistance spot weld comprising:

• providing a spot welder having an electrode electrically coupled to a weld controller;
• supporting said electrode on the piston rod of a cylinder assembly having a cylinder housing, said electrode and said piston rod being displacable with respect to said cylinder housing;
• monitoring the relative displacement between said electrode and said cylinder housing using a transducer and creating a displacement signal responsive to relative displacement therebetween;
• determining whether proper part fit up is achieved prior to the initiation of welding by monitoring the displacement signal utilizing a microprocessor controlled monitor which is coupled to the weld controller;
• compensating for electrode wear prior to the initiation of welding by monitoring the displacement signal utilizing said microprocessor controlled monitor;
• initiating welding;
• varying weld duration by monitoring electrode displacement which occurs as a result of welding;
• identifying good and bad welds by monitoring electrode displacement which occurs as a result of welding;
• determining weld expulsion by monitoring electrode displacement occurs as a result of welding;
• pressurizing the cylinder assembly after the completion of a weld so as to retract the electrode;
• signalling a fault condition if the electrode has not retracted after the cylinder assembly is pressurized;
• and
• determining the amount of electrode wear based upon the displacement signal .