PVC pipe causes cold material spot

Date: 2012-12-03 05:40 Author: 3392 Views Views Font Size: Big Mid Tiny

In PVC pipe fittings manufacturers, many small and medium enterprises, due to differences in the backward on the device or on the quality of workers, resulting in the production of PVC pipe fittings will find a variety of problems, recent home manufacturers of PVC pipe production, white spots appear following the Guangya building materials to provide a point of information:

PVC pipe may be cold material spots into two: one caused by the material temperature is too low materials plastics bad, generally known as cold material spots; another is the injection too fast near the gate the massive formed similar to the butterfly-shaped marks, also known as Hu Dieban.

(1) cold material spots elimination

The cold slug spots generated caused because the material is too raw. Its causes: lower material temperature plastics bad. Can:

① warming, mainly district temperature rises, and enhance every 2 to 4 degrees;

② increase in the pre plastic pressure, flow, doing so can increase the speed of the screw, so that the material and the barrel wall friction increases, generate a lot of heat, so as to improve the material temperature purpose.
Note: these two heating methods have advantages and disadvantages, the temperature may have done good materials, plastics, higher temperatures, the material easy to decompose, bubbles, silver, red lines, the event of such defects, lower the temperature is very difficult. , while the increase in pre-plastic pressure, flow rate, can keep the temperature constant, so that the operating space increases.

(2) Hu Dieban-elimination

Hu Dieban generated mainly due to the injection speed is too fast caused this can be eliminated by reducing the injection speed. Under normal circumstances, the secondary injection pressure and flow reduction, to reach an appropriate value, but this value should not be too small, to prevent injection of a full cavity difficult. In this case, note that the operating panel, two stroke long or too low pressure flow, time was needed to finish this trip, the product should not be played. Further, the vicinity of the product gate Matte

In addition:

Check the mold core and cavity waterway is smooth, if the mold is very hot, but also may lead to the white, commonly known as “burns”. Look at the picture seems to have contractions. The core internal Generally are trenching, if the middle Baffle Boards, the head of the water easily backlog and hot.

2, the plasticization of the raw material is not enough. Especially low nozzle temperature and back pressure is small, easy to cold slug hit product.

Is recommended that you put the product outlet tone light, if there is still a mass of white circle. Please check raw Gaifen whether too much, titanium dioxide, if qualified, as well as mixing, granulation process is normal. If you purchased raw materials directly to the supplier.

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