Hello and good morning/afternoon/evening to members of this community, 

In my organization, we have robot cells where the welding gun is mapped onto the 8th controlled axis instead of the normal 7th one - the reason why ? - I am not at all sure. Is there a way that when I import a program, I can define the welding gun to be the 8th axis instead of the 7th ?

Take the given arrangement for your understanding
 

For those familiar with ABB robots, the syntax below shows a target and the axis that is actuated by it - in this case 99.9977 mm but see that it is mapped onto the 8th axis:

As a work around, I have created a 'Dummy' 1 degree of freedom joint which consists of tag rotating about its axis and defined that as the 7th axis and then the welding gun itself is the 8th axis as shown in the motion group below:

With this arrangement, when I import the robot program, the welding gun opens and closes as expected and the translator is able to output with the correct mapping also. 

I just feel that there has to be a 'smarter' way of handling this than how we are doing so. 

Looking forward to your input and guidance,

Regards,
Omar