Improve The Quality Of Large Blow Molds
Jun 30, 2021
How do large blow mould companies improve the quality of blow moulded products? The importance of blow molding equipment to industrial production is self-evident. A large number of plastic products are made by blow molding. The common blow molding method is extrusion molding, and the problem of poor product quality will inevitably occur in the production process. Let us learn how to improve the quality of blow molding products with large blow mold manufacturers.
Blowing pressure: Blowing pressure can expand the semi-molten tube blank to form the desired shape against the cavity wall, and it can also cool the blow-molded product. Generally, if the inflation pressure of large volume is too large or too small, it is not conducive to production. Therefore, it is more clear to select the appropriate pressure product.
Blowing speed: In order to shorten the blow molding time and quickly obtain blow molded products, a large amount of air should be injected in a short time to ensure uniform and rapid expansion of the cavity and shorten the cooling time in the cavity.
Large blow mould temperature: mould temperature has a great influence on the appearance of blow moulded products. Generally speaking, the mold temperature should be cooled as evenly as possible. The mold temperature is related to the type of plastic, the thickness and size of the product.
If the temperature of the large blow mold is too high, the cooling time will be extended, the production cycle will increase, and the productivity will decrease. At this time, if the cooling is not enough, the mold release deformation, shrinkage rate and surface gloss of the product will deteriorate. Generally, for plastics with strong molecular chain rigidity, the mold temperature is higher; however, for plastics with flexible molecular chains, the temperature of large blow molds should be lower.
What should be controlled in the production of large blow molds? The fluctuation of the geometric figure size after blow molding is a common deficiency, which is a common situation:
For different types of plastics, the control of material temperature and mold temperature requires different temperature adjustments. The fluidity of the plastic profile is poor, and the application conditions of the two mixtures are different. Generally, it is easy to ensure that the plastic profile is manipulated within the fluidity value range, but the manipulation of the mold temperature is very complicated. The different geometric shapes, sizes and wall thickness ratios of different molded parts have certain regulations on the refrigeration system. Therefore, the mold can be kept at the allowable ultra-low temperature as much as possible, which is conducive to reducing the injection cycle time and improving productivity. When the mold temperature changes, the shrinkage rate will also change. The temperature of the large blow molding mold will be maintained for a long time, and the dimensional accuracy will be stable, avoiding defects such as deformation of the molded part, poor gloss, and cold spots.
Make the processing performance of the plastic in a better state. Naturally, there is a whole adjustment process, especially the two-cavity mold forming part is more complicated. Therefore, the mold temperature cannot be modified randomly during the processing, and the mold temperature should be set within the strongly recommended raw material temperature range.
