The correct solution for yellowing of transparent products during injection molding is shared by inj

The correct solution for yellowing of transparent products during injection molding is shared by injection molding factory

First, what is injection molding machine?  

Injection molding machine, also known as injection machine, many factories called beer machine (PI JI), injection products called beer parts.  It is the thermoplastic or thermosetting plastics using plastic molding mold into plastic products of various shapes of the main molding equipment.  The injection molding machine heats the plastic, applying high pressure to the molten plastic so that it shoots out and fills the mold cavity.  

Two, injection molding generation processing  

The proper molding temperature setting is related to many factors, such as the size of injection molding machine, screw configuration, mold and molding product design and molding cycle time, etc.  In general, a lower temperature is set in the back/feed zone and a higher temperature is set in the front of the tube to allow gradual melting of the plastic.  However, if the screw design is improper or L/D value is too small, the reverse temperature setting can also be used.  

Melt temperature is very important, the temperature of the injection cylinder used is only a guide.  The temperature of the melt can be measured at the nozzle or by air injection.  The temperature setting of the injection cylinder depends on the melt temperature, screw speed, back pressure, injection amount and injection cycle.  If you have no experience working with a particular grade of plastic, start at the lower setting.  For ease of control, the cylinders are divided, but not all are set at the same temperature.  If operating for a long time or under high temperature, please set the temperature of zone 1 to a lower value. This will prevent premature melting and shunting of plastics.  Before injection, ensure that the hydraulic oil, hopper sealer, mold and injection cylinder are at the correct temperature.  

Nozzle pressure is the pressure in the mouth.  It is roughly the pressure that causes the plastic to flow.  It has no fixed value, but increases with the difficulty of mold filling.  There is a direct relationship between nozzle pressure, line pressure and injection pressure.  On spiral injection molding machines, the nozzle pressure is about ten percent less than the injection pressure.  In the piston injection molding machine, the pressure loss can reach about ten percent.  In the piston injection molding machine, the pressure loss can reach 50 percent.  

When molding POM (acetal), PA (nylon), PBT and PET (polyester) semi-crystalline engineering plastics, to ensure that the processing mold surface temperature is appropriate, this point is very important.  Satisfactory machining requires full consideration of die design.  Only when the mold design is in place can the processor use temperature control equipment to produce high quality molding products.  In order to avoid production problems in the follow-up process, it is required to consider the combination of mold design at the initial stage of design.  

The injection time here refers to the time required for plastic melt to fill the cavity, excluding the auxiliary time of mold opening and closing.  Although the injection time is very short and has little effect on the molding cycle, the adjustment of injection time has a great effect on the pressure control of the gate, runner and cavity.  Reasonable injection time is helpful for melt filling, and it is very important to improve the surface quality of products and reduce the size tolerance.  

Iii. Root cause of yellowing of transparent products of injection molding manufacturers and improvement plan  

Common features of fully transparent raw materials  

Transparent plastic, because of the high light transmittance to provisions plastic manufacturing process performance, demanding no can have all the decorative pattern, air flow, pale, fog is dizzy, small black spots, fading, poor gloss, such as faults, so the whole process of injection molding in the injection molding processing all of raw materials, machinery, equipment, molds, to product design, be very careful and strict rules are put forward.  

Because transparent plastic see high solution point, poor fluidity, in order to ensure the process performance of the product, usually in the higher temperature, injection pressure, injection rate and other main processing parameters for small adjustment, so that the injection plastic can not only fill the mold, and not easy to cause thermal stress caused by product deformation and cracking.  Because transparent plastic see high solution point, poor fluidity, so in order to ensure the process performance of the product, usually in the higher temperature, injection pressure, injection rate and other processing parameters for small adjustment, so that the injection plastic can not only fill the mold, and not easy to cause thermal stress caused by product deformation and cracking.