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With the tenet of “be sincere, be scientific”, Nanjing Chengke company focuses on the works of R&D , design, sale and after-sale for co-rotating & counter-rotating twin-screw extruders, tandem compounding lines and single-screw extruders.
Chengke was founded by senior engineers in twin-screw processing，we have advanced management systems and high-effective operation teams. Our business concept is to analyze the problems, to offer the best solutions and to provide custom mouldings. High-beginning, high-quality, and optimal designs are our company’s characteristics, which can meet the first-class product quality standard as other companies worldwide.
we focus on the works of twin screw:
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Two-stage compounding line
Whatever single screw or twin screw extruder, for ordinary use, materials from feeding to extruding, all need the steps: solid conveying, melting, compounding, degassing and extruding etc. Normally, different step requires different screw structure, different operating conditions, such as the RPM, barrel heating temperature, material pressure, etc. We can provide different screw structure to each step, also can set different temperature for different step, but because all these extruding steps finished on the same screw shaft that means the screw rotary speed is the same, each step temperatures must influence each other step. All these cause pressure building-up, energy inputing can not carry out according to individual step requirement. So for the best extruding scheme, because of above facts, it does not work. For example, to increase the output of single screw extruder, for conveying step, we’d better choose the screw structure like this: deeper groove depth, longer screw distance, higher RPM, lower die pressure and lower extruding temperature, etc. But if so, the melting step must be influenced. Higher RPM means the conveying speed would be faster, so it would influence the melting effect. Sometimes for better mixing, we use the kneading elements, it not only provides better compounding also high temperature. If the materials with the character of temperature sensitive, this kneading element may cause materials degraded. For twin screw extruder extruding, the steps also include solid conveying, melting, conveying, compounding and degassing etc, so conflicts and influences also exist. To solve these problems, people put forward the concept: two stage extrusion line, put the extruding steps on two extruders. First extruder mainly for materials melting and compounding, second extruder for pressure building-up and extruding etc. PVC cable material, sole material, clarity bolt material, medical material; Low-smoke and no-halogen material or Low- halogen and flame retardant material; EVA screen material, PE and EVA masterbatch, etc..
Combine high-speech and strong-compounding of twin-screw extruder with low-speech, low-temperature and weak-shear of single-screw extruder. It is the first choice when produce heat-sensitive or shear-sensitive material.