The air bubbles in plastics parts
The air bubbles is one of the types of surface defects parts. Good to know how to distinguish different types of bubbles and how to eliminate those filled with air. Blank spaces in the form of bubbles formed on parts as a result of entering into the air surrounding it to form and stop by. The resulting vesicles resemble its appearance cavity cramps (wakuole). Why are there bubbles? During the injection stop is surrounded by the air mass, resulting in a part in empty space (air bubble), which may occur in the vicinity of the wall. It is the result of too much or too rapid decompression stroke, low power plastification, as well as problems with the venting (eg, ribs, blind holes). How to distinguish from wakuole bubbles? In the case of the surface defects it is important to distinguish between the air bladders and jam shrinkage. Cramps cavity is empty spaces without air (so-called empty vesicles. Wakuole), which arose as a result of difficult shrinking plastic. Since the air bladders and cavities cramps are similar in appearance, it is difficult to distinguish them from each other. Helpful in their distinction may be part of immersed in water and see whether it affects them (wakuole) or not (gas bubble). The defect, which are air bladders, it is less, where the manufacture takes place without decompression stroke. Changes in pressure at the end of clamping and its duration have no effect on the volume of empty space. Parts, where there are empty spaces, tend to have much less resistance. For items that are not transparent, some of them should be cut in order to ascertain the potential for defects. When the mass injection rate may enclose air, resulting in a part in empty space, which often have less strength. It should be remembered for cutting the items that are not transparent and reviewed them for possible defects. It is important for the differentiation defects in the surface filled with air bubbles from those which are empty. Bubbles on part can be addressed by taking appropriate proceedings, such as reducing the rate of stroke and decompression.