Precision Injection Plastic

The precision injection molding refers to the back of the formation product accuracy(including size precision, shape precision and mutual position precision) and the surface quality (for example surface roughness, stress condition and superficial air bubble, silver grain conditions and so on),it requests the very high handicraft technology. The precision injection formation must use precision injection mould. The design and the manufacture of precision injection mould play an important role in the precision product size precision, therefore, injection mould formation and spare part’s shape, the size, the precision, the surface quality, the intensity, and the rigidity all have special requests. Its characteristic mainly concentrates the following several aspects.

一、Mould Precision

(1)Must guarantee the precision injection product accuracy, first must guarantee the mould precision, including the mould cavity size precision, the profile precision and so on. The concrete measures include: the size of against pole is smaller than the convention mould size, the cavity number is not too excessive, thickness of the ledger wall, the backing strip, the backing and cavity wall should big somewhat and so on.

(2)Mould Processing NatureIn the mould design processing, must consider mould processing nature, for example: when design the shape of complex precision injection mould,the best design make the cavity piece together structure, not only it is advantageous to the abrasive machining and exhaust and heat treatment, but must guarantee piecing together precision., in order to avoid the product appearing piecing together seam grain. In addition, but also must consider the installment position about the temperature measurement and the cooling system.

(3) Product Separates From the Filmthe sharp of precision injection molding product is generally complex and processing injection pressure is high, therefore, the product separate from the membrane is difficult. In order to prevent product separating from the membrane distort may affect the precision, when design the mould, besides must consider the separated membrane ascent, but also must enhance the cavity and the flow channel smooth finish, reduce the cavity number, apply less and short flow channels, and the push pedal seprating film as soon as possible.

(4) Mould Material QualitySince the precision forming mould must withstand the high injection pressure and the high locking force, and keep high accuracy for a long time, therefore, manufacture mould material have to choose high quality alloy steel with high hardness degree、good friction nature、good corrosion resistance and the high mechanical strength.

二. Precision Injection Plastic Forming Machine

High quality product of precision injection formation need to carry on in the special-purpose precision injection machine. The precision injection formation craft raises some requests for injection machine.

(1) Injection Power Is GreatPrecision injection plastic forming machine has bigger power than an ordinary injection machine to satisfy high-pressured and the high speed injection condition, thus guarantee the product size deviation scope is small, the size stability is high.

(2) Control Precision Is High The higher controlling precision of injection plastic forming machine mainly manifests the following several aspects.

2.1 Craft Parameter Redundant precision Is Very HighPrecision injection plastic forming machine implements the multistage reaction control, for the injection quantity, the injection pressure, guarantees pressure, multifeedback pressure and screw rod rotational speed ,use PID for the material tube temperature and the spray nozzle temperature (proportion integral differential) to control, cause to control temperature precision in ±0.5℃, thus guaranteed these craft parameter stability and the reproducibility, avoided affecting the product precision because of the craft parameter changed. In addition, injection plastic forming machine can warning and diagnosing the disadvantages causing the entire craft process at the steady state.