Extruder Filter On The Impact Of Plastic Extrusion

in Filter

HC WIRE: In the extruder the extrusion process, molten material is transported through the filter to Mold . Filter to be filtered material, and can improve the mixing of materials. However, the filters can process also fluctuate, leading to increased back pressure and melting temperature materials, and sometimes less.

Extruder filter is fixed in a porous or tank protection board, this could make between the extruder and die seal. Clean filter pressure generated by small, probably only 50 ~ 100lb/in2 (1lb = 0.4536Kg, 1in = 25.4mm). With the pressure increasing, the retention of resin-line filter in the number of impurities becomes more and thus blocking filter.

Filter will affect the temperature of molten material

When changing the blocking filter, the pressure will suddenly drop the temperature of molten material may drop, resulting in a change in product size. In order to maintain the same size product, you can adjust the extruder Screw Speed, you can adjust the linear speed of extrusion machine. In the circular extrusion products, these changes may not lead to serious problems, but out of the flat or irregular in shape product, melting material temperature may affect the product dimensions. For example, in a flat mold, the molten material may cause cooler center and thin sheet, Er Shi surrounding partial thickness. This can be through automatic or manual adjustment of the mold be corrected.

Filter converter in the back, with a molten material to ensure stable access to the mold of gear pumps, can prevent these problems. However, the molten material in the filter change occurred after the temperature of the mold still need to solve the problem. The same time, gear pumps hard impurities easily damaged, therefore, the gear pump also needs to be fine filter protection.

Some hard PVC Processors do not want to use the filters of the reason is that the filter will PVC Easily happen melting temperature material degradation, which will require better thermal stability of the material, thus increasing the cost of materials. If you use PVC converter special filters will increase the cost. So most of the hard PVC processors or avoiding the use of filters or use the coarse converter without filter, filter only the larger particles of impurities.

How to choose the filter Extruder wire is the most commonly used metal filter material. Although stainless steel is more expensive, but can be used in some PVC production line or elsewhere to avoid rust. Nickel filter was used to avoid corrosion by fluorine polymer or PVDC occasions.

General, filter screen eye (or the number of wires per inch) 20 to 150 or more. 20 sieve eye filter fairly thick; 40 ~ 60 Screen filter more fine eyes; 80 ~ 150 screen eye filter is very fine.

Most of the screen filter box weave eyes were tested in each direction, the same number of metal wire. Dutch law is woven coarse horizontal wire, and provides for the even number, for example, 32x120 root / in (1in = 25.4mm). Woven with the Dutch legal system do not have the filters set in parallel mesh filter device can play the role of fine filtration.

Eye screening the same number of filters of pore size is based on wire diameter to determine, and do not need exactly the same. For example, the spacing for the 24in, diameter 0.02in 20 made of metal wire screen eye filter, the openings on each side for the 0.01in; while the spacing for the 30in, 0.01in diameter made of metal wire 20 sieve eye filter, which each side of the hole slightly larger for the 0.04in. This is because the thin metal wire of the filter is not detailed enough, and more easily blocked (1in = 25.4mm).

In general, filter the devices are: protection against the most coarse filter plates, while the smallest filter is the face of extruder.

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Extruder Filter On The Impact Of Plastic Extrusion

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This article was published on 2010/10/20