Sizing device design requirements of PE three-layer co extrusion pipe equipment


Ningbo Fangli Technology Co., Ltd. is a mechanical equipment manufacturer with nearly 30 years’ experiences of plastic pipe extrusion equipment, new environmental protection and new materials equipment. Since its establishment Fangli has been developed based on user’s demands. Through continuous improvement, independent R&D on the core technology and digestion & absorption of advanced technology and other means, we have developed PVC pipe extrusion line, PP-R pipe extrusion line, PE water supply / gas pipe extrusion line, which was recommended by the Chinese Ministry of Construction to replace imported products. We have gained the title of “First-class Brand in Zhejiang Province”.


The sizing device in the die is the main component in the extrusion system of PE three-layer co-extrusion pipe equipment. The molten material is cooled down on the inner surface of the sizing sleeve, so as to form a solid surface layer to ensure the accurate outer diameter of the pipe. It also ensures the stability of pipes and normal traction and extrusion. The shape and failure conditions of molten materials in the sizing device directly affect the internal and external surface quality of pipes, and also directly determine the stability of the whole extrusion system and the reliability of high-speed production.


Therefore, a good sizing device design should meet the following requirements:

1. Good thermal conductivity provides sufficient surface cooling for molten materials in a short distance. The cooling speed can ensure that the surface of the pipe can quickly form the cortex of solid phase.

2. High wear resistance.

3. The inner surface shall have a high finish.

Different sizing structures can be selected according to different materials, production speed and quality requirements. At present, there are two popular sizing devices for PE three-layer co extrusion pipe equipment: cylindrical sizing sleeve and sheet combined sizing sleeve.

The cylindrical sizing sleeve is widely used in these two sizing devices. It has a wide range of applicable properties and can meet the requirements of PE pipes Φ 20- Φ Extrusion molding of 630:

1. For the cylindrical sizing sleeve, the stability and uniformity of the fire flow introduced into the fire ring directly affect the extrusion quality of the pipe, while the cooling rate of the molten material in the sizing sleeve can directly affect the quality of the inner wall of the pipe.

2. The sheet combined sizing sleeve is mainly used for the production of PE pipes with large diameter and high-speed extrusion. The applicable diameter range is: Φ 20- Φ 63mm, the extrusion speed can reach 35m / min or higher according to the pipe diameter and processed materials. The sheet shaping device is composed of multi-layer thin copper sheets, with a sizing round hole in the middle and a static flow from a retracting support column on the outside. The distance between each layer of thin copper sheets is distributed according to the following rules: along the blank introduction direction. The distance between copper sheets increases gradually. Near the blank introduction end, the distance between copper sheets increases, so as to prevent the blank in plasticized form from accumulating and extruding between the sheets. With the failure of the hard layer on the surface of the pipe, the distance between copper sheets can be gradually increased.


Therefore, the reasonable selection of pipe sizing device plays a decisive role in the production quality and economic benefits of PE three-layer co-extrusion pipe.


If you need more information, Ningbo Fangli Technology Co., Ltd. welcomes you to contact for a detailed inquiry, we will provide you with professional technical guidance or equipment procurement suggestions.


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