Polycarbonate (PC) injection process

The PC or polycarbonate, due to their excellent mechanical properties, commonly known as bulletproof glue. PC has high mechanical strength, wide range of usage temperature, good electrical insulation properties (but anti arc properties unchanged),good dimension stability, transparency. Is widely used in electrical products,instrument, electronic product shell structures. Products are modified by PC, usually with the addition of glass fiber, mineral filler, chemical flame retardants, and otherplastic etc.. PC and poor flow properties, processing temperature is higher, so themany levels of processing modified material dedicated plastic injection structure.
1, plastic processing
PC high water absorption, processing before preheating and drying, pure PC drying at 120 ℃, modified PC in 110 ℃ drying for 4 hours. The drying time of not more than 10 hours. Generally available to air dry extrusion method to judge the adequacy of.
Using the ratio of up to 20% recycled material. In some cases, can be used 100% recycled material, quality requirements of real weight as products and. Recycled materials do not mix different color at the same time, otherwise it will seriously damage the product properties.
2, the selection of injection molding machine
Now the PC products because of cost and other aspects, multi use modified materials,especially electrical products, but also increase the fireproof performance, the flame retardant PC and other plastic alloy molding products, of plastics injection molding machine system requirements is well mixed, corrosion resistance, the conventionalplasticizing screw is difficult to do, in the purchase of when, must beforehand. Ramada Limited PC screw special for customers to choose.
3, the mold and the gate design
Common mold temperature of 80-100 ℃, 100-130 ℃ and glass fiber, small articles can be used needle gate, gate depth should be the most thick parts of the other 70%,circular and rectangular gate.
The gate of the bigger the better, in order to reduce the defect caused by excessiveshear plastic.
The exhaust hole depth should be less than 0.03-0.06mm, as a short and roundrunner.
Draft is usually 30 '-1 °.
4, melt temperature
Available to air injection method to determine the processing temperature. General PCprocessing temperature of 270-320 ℃, some modification or low molecular weight of PC is 230-270 ℃.
5, the injection speed
See more with injection molding speed Piankuai, such as playing electric switch parts.Common to slow, rapid prototyping.
6, the back pressure
About 10bar back pressure, in the absence of gas lines and color mixing case may be appropriate to reduce the.
7, retention time
The long residence time at high temperature, the material will be degraded, or CO2,turns yellow. Do not use LDPE, POM, ABS or PA cleaning barrel. Application of PScleaning.
In 8, the matters needing attention
Some modified PC recovery, because too many times (low molecular weight) or various component mixing uneven, prone to dark brown liquid bubble.