Detailed description of film blowing and expansion ratio

The blow ratio of PE film blowing machine is one of the key points of blow molding process control. The expansion ratio is the transverse expansion multiple of the film. In fact, it is the transverse stretching of the film. The stretching will have a certain degree of orientation effect on plastic molecules. With the increase of the expansion ratio, the film becomes thinner. Although it can save materials, the film is prone to wrinkles.

The strength of the film decreases; If the blowing ratio is too small, the consumption will increase, the effective volume of the product will become smaller, the product will become thicker, the cooling time will become longer, and the cost will increase. Most PE is used for film blowing and film processing. General low density PE (LDPE) or linear low density PE (LLDPE) are available. HDPE film grade is generally used where superior tensile property and good impermeability are required.

For example, HDPE film is commonly used in commodity bags, grocery bags and food packaging. PE film processing generally uses ordinary film blowing processing or flat extrusion processing. The film can be widely used in light and heavy packaging because of its good barrier, fresh preservation, moisture prevention, frost prevention, oxygen isolation and oil resistance. Such as all kinds of fresh fruits, meat food, pickles, fresh milk, liquid drinks, medical supplies, etc.

If the non professional film blowing machine or the film blowing machine does not use the correct method in the processing process, the film material may also be inferior. If the noise source during driving is the gearbox, it may be caused by the wear of gearbox bearing or gear and bearing spots.

The transmission makes abnormal noise when accelerating and shifting. It may be that the transmission oil contains metal powder, indicating that the brake belt clutch and other components in the transmission are excessively worn. Solution: there are many transmission parts, and the causes of noise are complex. During analysis and judgment, attention should be paid to whether it is related to specific speed. For example, the sound of some planetary teeth is obvious at about 50km / h.