Reference to 7.5.2 is a red herring IMHO. There is sufficent reference to use of documented procedures (confusingly called work instructions) here:
There are plenty of processes where it is possible to verify the output (so not covered by clause 7.5.2) but, for reasons of speed or cost you wouldn't want to do this on every product. instead an organisation might choose to document the production procedure as a means of providing additional control of the process.
Clause 7.5.2 only applies to processes and the requirement for is after the process has been validated. An example might help:
Welding is one of the classic special process that comes under 7.5.2. In many industries where welding is used control is exercised through use of competent people. In others it is through use of calibrated equipment and in many industries - particularly using structural or safety critical welds welding procedures are developed covering:
Of course when this procedure is issued people can choose whether they follow it or not.
There are plenty of processes where it is possible to verify the output (so not covered by clause 7.5.2) but, for reasons of speed or cost you wouldn't want to do this on every product. instead an organisation might choose to document the production procedure as a means of providing additional control of the process.
Clause 7.5.2 only applies to processes and the requirement for is after the process has been validated. An example might help:
Welding is one of the classic special process that comes under 7.5.2. In many industries where welding is used control is exercised through use of competent people. In others it is through use of calibrated equipment and in many industries - particularly using structural or safety critical welds welding procedures are developed covering:
- welder qualification;
- equipment type and calibration;
- number of welds;
- direction and orientation of each weld pass;
- the welding consumables to be used for each pass;
- speed and feed rates for weld consumables to control material deposition; and
- post weld treatment processes
Of course when this procedure is issued people can choose whether they follow it or not.
Welding using certified welders as you described probably better fits under 7.5.2 b "approval of equipment of and qualification of personnel".

1 There are certain situations in most organisations where inputs are turned into outputs (process) in a better way if the person / people working in the process follow a prescribed set of steps in a certain way (procedure). For ease of reference this is often captured in media in some way (documented). It may or may not be possible to verify through monitoring or measuring that the output is correct.
: