PLASTIC EXTRUDER TIPS 3: SINGLE SCREW EXTRUDER COMPONENT INTRODUCTION

Single Screw Extruder Component Introduction

Posted by Andy

Electric component please check here: Twin Screw Extruder Introduction

The main extruder is also consist of motor, gearbox, screw, barrel, heater, cooling system etc.

1.For our extruder, the extruder motor normally uses SIEMENS Beide / WN brand. But it has a standard type or separately air fan force cooling type. If your local temperature will always keep high degree, please choosing force cooling type.

2.There are two types gearbox for the single screw extruder: standard rotary speed gearbox and high-speed type. Standard type: 0-120 rpm, high-speed type: 0-150 rpm. Reducer type:hard-toothed surface gear reducer, helical gear transmission. Gear is made of high strength low-carbon alloy steel with normalizing and quenching treatment, hardness HRC58-62, adopted numerical control grinding processing, gear accuracy is GB10095-88, 6 class.

3.There are three main feeing systems for material feeding into the extruder. One is the hopper connected with barrel directly(like the photo), we normally use it for hard flake scrap, then using one conveyor belt to control the feeding speed. Second is using one single screw for scrap or pellets feeding. Third is force feeding type. Depends on the raw material.

4.The barrel is normally made of 38CrMoAlA, inner surface nitriding treatment on the forgeable piece. Nitration case depth: 0.5-0.6mm, hardness: HRC65+/-2. Inner face roughness:≤1.6um. Except this, we also have the barrel made of Ni-Cr alloy, wear & corrosion resistance with 3 times lifetime than the normal one.

5.The screw is made of 38CrMoAlA, nitriding treatment on the forgeable piece. Nitration case depth: 0.5-0.6mm, hardness: HRC63+/-2. Screw and screw groove surface roughness ≤0.8um. Screw surface electroplated layer thickness: 0.03mm–0.4mm. Except this, we also have the screw made of Ni-Cr alloy, wear & corrosion resistance with 3 times lifetime than the normal one. And also for different material and function, we have a different design for the screw.

6.There are several choices for the extruder heater, like coil heating, aluminum sheet heating, cast aluminum/copper, electromagnetic heating, infrared heating. We normally use cast aluminum/copper heating, heating fast & longer lifetime with competitive price.

7.There are two ways for barrel cooling, fan cooling & water cooling. The temperature of extruder drop down faster with water cooling than fan cooling, but sudden temperature change may be not suitable for some material.

8.The degassing device divided into two type, nature degassing & vacuum pump degassing, to removing the moisture inside the material.

9.The thermocouple is using for detecting the barrel temperature, and then give a signal to OMRON temperature control system, automatically control the heater heating or fan cooling.

10.The screen exchanger is for removing some dirt from the melted plastic. It will have a sieve inside, and we normally suggest customer use with 60-100 mesh sieve. If the sieve size is too small, the pressure of extruder die-head will be always very high, that will need to change the screen frequently.

If you want to know more information about a plastic pelletizing machine, please contact:

Mr.Andy, WhatsApp:+86-18550112020, Email: weishunzhou@gmail.com

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