PET Preform Mould Common Problems And Corresponding Solutions
What are the defects of PET Preform Mould bottle embryo mold? What is the cause of the defect and how to exclude it?
PET Preform Mould plastic injection molding process is a very important plastic processing technology, one for PET Preform Mould Preform Mould, in most cases, plastic packaging plant will be used to blow molding the way the production process, but the injection molding process is particularly unique processing advantages , For PET Preform Mould injection molding, the technical staff need to consider many factors, as follows.
PET Preform Mould bottles through the blow molding re-processing to form plastic bottles, including cosmetics, medicine, health care, beverages, mineral water, reagents and other packaging used in the bottle, this bottle method is called two-step method, that is, through the injection molding process, Blow molding process to form PET Preform Mould Preform Mould. The quality of PET Preform Mould bottles depends on the quality of the supply of preforms. The following is a common problem with PET Preform Mould bottles in the production of PET Preform Mould bottles and the corresponding solutions.
PET Preform Mould chemical called polyethylene terephthalate, also known as polyester. Currently used in the customer is the most GF-PET Preform Mould, mainly to play the preform.
The glass transition temperature of PET Preform Mould is about 165 ℃, and the crystallization temperature of the material is 120 ~ 220 ℃. PET Preform Mould has a strong hygroscopicity at high temperatures. For glass fiber reinforced PET Preform Mould materials, bending deformation is very prone at high temperatures.
The degree of crystallization of the material can be increased by the addition of a crystallization enhancer. Transparent products processed with PET Preform Mould have gloss and thermal distortion. Special additives such as mica can be added to PET Preform Mould to minimize bending deformation. If a lower mold temperature is used, transparent products can also be obtained using non-filled PET Preform Mould materials.
Injection molding is mainly used to enhance the molding of PET Preform Mould. Usually using screw-type injection machine. Screws are generally required to be hardened to avoid abrasion after prolonged use. The length of the injection nozzle hole should be as short as possible, its diameter should be controlled at about 3mm.
Enhance the melting point of PET Preform Mould up to 260 ℃, in order to prevent nozzle clogging, should install a larger power heater. In addition, the tip of the nozzle hole is preferably machined into an inverted cone as shown in Fig. 1 so that the molten material in the flow path and the nozzle can be easily cut off.
Injection molding is mainly used to enhance the molding of PET Preform Mould. PET Preform Mould under normal circumstances can only use screw-type injection molding machine.
It is best to use the top of the mutant screw with a reverse ring, the surface hardness and wear resistance, length and length ratio is not L / D = (15 ~ 20): 1 compression ratio of about 3: 1.
L / D too much material in the barrel to stay too long, excessive heat easily lead to degradation, affecting product performance. Compression ratio is too small shear heat less, easy to plastic poor, poor product performance. The glass fiber will be more broken, mechanical properties decline. Processing of glass fiber reinforced PET Preform Mould, the barrel wall wear more powerful, the use of wear-resistant materials such as manufacturing or lining with wear-resistant materials.
The nozzle is short as well, the inner wall requires polish, the aperture is as large as possible. It is better to use hydraulic brake valve type nozzle. The nozzle must be kept warm and the temperature is controlled to ensure that the nozzle does not freeze. But the nozzle temperature can not be too high, otherwise cause salivation. Before the start of molding must use low-pressure PP material, the barrel clean.
PET Preform Mould molding temperature range is narrow, the temperature will directly affect the level of product performance. If the temperature is too low, the plastic is not good, so that plastic parts depression, lack of material and other defects; the other hand, the temperature is too high, will cause overflow, nozzle salivation, color deepening, mechanical strength decreased, and even cause degradation. Usually, the cylinder temperature is controlled at 240 ~ 280 ℃, the temperature of the glass reinforced PET Preform Mould is 250 ~ 290 ℃, not more than 300 ℃, the nozzle temperature is generally lower than the cylinder temperature 10 ~ 20 ℃.