The essay analyzes the problem of blow-hole which is easily seen in the process of production and makes further discussion of the technology of improving lid casting.
She uses her mouth to blow the water to make a current, then her blowhole to break the current into a ring shape.
她会用嘴吹出一个气泡，然后用喷气孔将气泡吹成圆环。
3
The reason and prevention of four kinds defects including surface wrinkled skin (carbon built-up), chock, blowhole, deformation, was introduced in this part of the article.