01 nozzle

The melt usually flows from the nozzle into the nozzle, but in some molds, the nozzle is part of the mold because it extends to the bottom of the mold. In addition, there are two main types of nozzles: open and closed nozzles. In injection molding production, open nozzles should be used more because they are cheap and have less possibility of retention.

02 filter and combined nozzle

03 exhaust

Here, the gas can be discharged from the hole or hole in the injection cylinder. Then the diameter of screw root increases, and the melt glue of devolatilization is adapted to the nozzle. The injection molding machine equipped with this facility is called exhaust injection molding machine. The exhaust injection molding machine should be equipped with a good smoke exhauster for catalytic combustion to remove the harmful gases.

In order to get high-quality melts, the plastics should be uniformly heated or melted and mixed thoroughly. Proper melting and mixing can only be achieved by using the correct screw, and there is sufficient pressure (or back pressure) in the injection cylinder to obtain mixing and thermal consistency.

05 check valve

06 screw retraction (inverted cable)

07 screw pad

08 screw rotation speed

09 glue injection quantity

10 plasticizing capacity

11 plasticizing capacity estimation

12 injection cylinder residence time

The actual residence time can be determined by experiments. The method is to measure the time required for colored plastics to pass through the injection cylinder. It can be roughly calculated by the following formula: T = (rated charge GX cycle time s) / (injection rate gx300). Please note that some plastics have a longer residence time in the injection cylinder than the calculation time, because they can agglomerate in the injection cylinder.

As a general practice, the residence time of a plastic on a specific injection molding machine should be calculated. In particular, when the large injection molding machine uses a small amount of injection, the plastic is easy to decompose, which is not detectable from observation. If the residence time is short, the plastic will not plasticize evenly; if the residence time is longer, the properties of the plastic will decline.

14 injection cylinder temperature environment

The temperature in the other regions is gradually increased until it reaches the nozzle. In order to prevent dripping, the temperature at the tip of the nozzle is often slightly lower. Molds are also heated and cooled, and because of the size of many molds, molds are also distinguished, but unless otherwise specified, each zone should be set to the same size

It can be measured by nozzle or air jet method. When the latter is used for measurement, care must be taken to ensure that there is no accident when cleaning the hot-melt plastic, because the high temperature of the hot-melt plastic can burn or even corrode the skin. In the injection molding workshop, burns are accidental.

16 mold temperature

17 uniform cooling

18 temperature and cooling check

always check whether the injection molding machine is set and running at the temperature specified on the record sheet. This is very important. Because the temperature will affect the surface finish and yield of injection molded parts. All measured values must be recorded and the injection molding machine checked at the specified time.