Functional analysis of blow molding equipment Feeding method, standard, distribution These factors directly affect the flow direction, density distribution, packing pressure and forming time. The direct feed port and the feed port have a large cross section (the thicker outer section) is reduced but the directivity is large, and the feed port width and the short length are small. Shorter than the feed inlet or parallel to the flow direction, the diameter is shortened.
Molding conditions The mold temperature is high, the molten material cools slowly, the density is high, and the shortening is large. Especially for the crystallized material, the crystallinity is high and the volume is changed greatly, so the shortening is larger. The mold temperature distribution is also related to the cooling and density uniformity of the blow molding box, which directly affects the shortening amount and directionality of each part. In addition, adherence to pressure and timeliness also has a greater impact on shortening, while pressure is large and time is long, but the direction is large. The injection pressure is high, the viscosity difference of the melt is small, the interlaminar shear stress is small, and the elastic rebound is large after demolding, so the shortening can also be appropriately reduced, and the material temperature is high and the diameter is shortened, but the directivity is small. Therefore, factors such as adjustment of mold temperature, pressure, injection speed, and cooling time during molding can also appropriately change the blow molding box shortening. According to the shortening plan of various plastics, the wall thickness and shape of the blow molding box, the standard and distribution of the feed port method, and the shortening rate of each part of the blow molding box according to the experience, and then calculate the cavity standard. For high-precision blow molding boxes and when it is difficult to grasp the shortening rate, it is generally preferable to describe the mold by the following method.
First, try again and modify the skill conditions to modify the shortened value slightly to meet the needs of the blow molding box.
Second, modify the mold according to the shortening of the internship.
Third, take a smaller shortening rate for the outer diameter of the blow molding box, and take a larger shortening rate for the inner diameter to leave the modified position after the test. China Resin R Online is the best database for building and building China Resin!
Fourth, the blow molding box to be disposed of after the post-disposal judgment standard changes (measurement must be 24 hours after demolding).
5. Test mode determines the casting system method, standard and molding conditions.
When the blow molding box is molded, the molten material contacts the surface of the cavity and the outer layer is cooled to form a low-density solid outer casing. Due to the poor thermal conductivity of the plastic, the inner layer of the blow molding box is slowly cooled to form a high-density solid layer that is shortened. Therefore, the wall thickness, the slow cooling, and the high-density layer thickness are shortened. In addition, the presence or absence of inserts and insert plans and quantities directly affect the flow direction, density distribution and shortening of the resistance, so the characteristics of the blow molding box have a great influence on shortening the size and direction. Blow Molding Machine, Zhangjiagang Blow Molding Machine, Blow Molding Machine
The blow molding machine has the volume change of the crystallization shape during the molding process of the blow molding box, the internal stress is strong, the residual stress in the blow molding box is large, and the molecular orientation is strong, so it is compared with the thermosetting plastic. The shortening rate is large, the shortening rate is planned to be wide and the directionality is obvious, and the shortening rate after molding, the annealing rate after the annealing or the humidity conditioning treatment is generally larger than that of the thermosetting plastic.
2018 11/16