In the 2nd picture, the point have

In the 2nd picture, the point have problem “high cove”. Because, it has less space in the welding.
In the 3rd picture, it’s good product. It welded by employee have high skills.
In the 4th picture, it’s NG product. the inside have not welding rod.

We known, the problem is skill of employee. But we can not train employee to high skill just one day.
Thus, We thought that, if we change use the brazing rod smaller. We can solve this problem.
Therefore, We will try to welding by brazing small size.