Calibration sleeve and its function


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 calibration sleeve is a component that assists the cooling and shaping of plastic pipes in the extrusion production of plastic pipes. It is installed at the front end of the vacuum calibration machine. After the pipe comes out of the mold, it enters the vacuum tank and spray cooling tank for further cooling through the calibration sleeve for preliminary cooling and sizing, until it is completely cooled and solidified, so as to achieve the purpose of sizing and obtain the pipe of the required specification.

Those engaged in the production of plastic pipes know that the calibration sleeve is very important in the forming of pipes, which directly affects the internal quality and appearance quality of pipes.

The main function of the calibration sleeve is to cool the tube blank of the extrusion die-head, fix the outer diameter of the pipe blank and correct the surface finish of the pipe.

The structure of the calibration sleeve directly affects the cooling effect of the pipe. Within the length of the calibration sleeve, the outer surface of the pipe must be hardened. When the pipe leaves the calibration sleeve, the hardening degree of the pipe wall must be sufficient to enable the pipe to support its own weight without deformation or fracture due to traction, otherwise the dimensional accuracy of the pipe will be affected.

Although the cooling effect can be improved when the length of the calibration sleeve is increased, there are problems such as increased processing difficulty, high manufacturing cost, inconvenient operation, excessive friction resistance, increased traction power, internal stress of the pipe, increased probability of deformation and fracture of the pipe, and reduced surface finish of the pipe. Therefore, the length of the calibration sleeve should be appropriate. The length of the calibration sleeve used by our company is generally 160-600mm. The length of the calibration sleeve of the same type increases with the increase of the pipe diameter (except for the specifications above PE800).

In addition, in order to improve the cooling effect, the calibration sleeve should be made of metal with good thermal conductivity. At present, most of the calibration sleeves for pipes at home and abroad are made of wear-resistant copper alloy. The calibration sleeves of our company are generally made of tin bronze (ZQSn 6-6-3).

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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