Method of controlling an indentation depth of an electrode into a metal substrate during welding

A method of controlling an indentation depth of an electrode into a first metal substrate during formation of a weld between the first metal substrate and a second metal substrate, the method comprising:

• selecting each of a weld force, a weld current, a weld duration, a minimum indentation depth of the electrode into the first metal substrate, and a maximum indentation depth of the electrode into the first metal substrate, wherein the electrode has a distal end having a shape defined by a radius of from about 35 mm to about 50 mm;
• selecting each of a second weld force that is less than the weld force, a second weld current that is less than the weld current, and a second weld duration that is less than the weld duration;
• selecting a third weld force that is less than the second weld force;
• clamping together each of the first and second metal substrates between the electrode and a second electrode, wherein the second electrode includes a second distal end defined by a second radius of less than about 20 mm;
• contacting the first metal substrate with the electrode to thereby apply the weld force to the first metal substrate;
• supplying the weld current to the distal end of the electrode to thereby initiate formation of the weld according to at least one of a first condition in which the indentation depth is less than the minimum indentation depth, a second condition in which the indentation depth is greater than or equal to the minimum indentation depth and less than or equal to the maximum indentation depth, and a third condition in which the indentation depth is greater than the maximum indentation depth;
• comparing the indentation depth to each of the minimum indentation depth and the maximum indentation depth to determine that formation of the weld is continuing according to one of the first condition, the second condition, and the third condition;
• if it is determined that the first condition exists, changing the weld duration without changing the weld current until the indentation depth is greater than or equal to the minimum indentation depth;
• if it is determined that the second condition exists, maintaining each of the weld force, the weld current, and the weld duration;
• and
• if it is determined that the third condition exists, ceasing to supply the weld current to the distal end of the electrode;
• after supplying the weld current for the weld duration, disposing the first metal substrate adjacent to and in contact with the electrode to thereby apply the second weld force to the first metal substrate;
• after disposing, supplying the second weld current to the distal end of the electrode for the second weld duration to thereby substantially form the weld so that the indentation depth is greater than or equal to the minimum indentation depth and less than or equal to the maximum indentation depth;
• after supplying the second weld current, disposing the first metal substrate adjacent to and in contact with the electrode to thereby apply the third weld force to the first metal substrate without supplying each of the weld current and the second weld current to the electrode.