Relating maintenance to product quality

[usenet91]

Hi all,

In my company (large steel-processing) the welding machine to create welds between coils faces a lot of availability losses.

Besides this weld breaks in the production line downstream the welding machine are occuring, resulting in quality losses. It is obvious that the weld breaks are caused by bad welding quality, which may be a result of a bad condition of the welding machine.

In order to improve the performance of the welding machine and simplify the analysis I divided the welding machine in several sub-systems. It is possible to allocate the availability losses to specific sub-systems by analyzing the failure registration system. Based on the allocation of the availability losses it is possible to define new maintenance policies to utimately improve the performance of the welding machine.

However, I have no idea how to allocate the quality losses to the identified sub-systems? And how to determine which maintenance policies can be used to avoid quality losses.

Do you know some methods of how to do this? A quantitative method would be most desirable, however a qualitative method is also sufficient. The ultimate aim is to improve the maintenance strategy (consisting of different policies) for the welding machine.

Thanks in advance!

 

[Jen Kirley]

Welcome to the Cove!

Identifying a link between maintenance of a welding machine (or its lack) and product quality would require a specific diagnosis of the cause of weldment issues. Such issues might include random fluctuations in current for an arc welder or jamming of wire in a mig welder. Can you identify such specific issues? Additional considerations might be the gas, gas bottle regulators and the wire itself. I didn't see what kind of welding process is being used so these are guesses.

 

[usenet91]

Thanks!

It's an arc welder, using flash butt welding to connect consecutive coils.

Your presumptions of the causes seem valid to me.

However, I am in a search for a method to analyze the causes in a structured way and then prioritize each sub-system regarding the influence on product quality.

Do you have any ideas?

 

[RoxaneB]

Why not host a problem-solving session with the people who do the job and are the experts in the current state of the process? Might help identify the root cause, facilitate action plan development and engage staff.

 

[BradM]

...

Besides this weld breaks in the production line downstream the welding machine are occuring, resulting in quality losses. It is obvious that the weld breaks are caused by bad welding quality, which may be a result of a bad condition of the welding machine.
...

Ok.... I just want to ask on this one....
Are you sure you have identified the true problem?

Can you say for sure that the people welding aren't related to this in any way?

 

[usenet91]

You are making a good point.
The presumption is that because of the significant availability losses concerning the welding machine the maintenance strategy is not effective.
Therefore, it seems valid to state that quality problems are also caused by the lack of maintenance. Presuming that quality losses occur before actual availability losses occur. Ofcourse, the human factor plays a role, but is not regarded as in scope.

A problem-solving approach would be probably suitable. Output of this session can serve as input for a FMECA and from that point new maintenance policies can be defined.