Lab Twin Screw Extruder Pelletizing Line

• Our pelleting extruder’s drive system consists of three parts: a motor, a coupling, and a gear box.
• The motor is a Siemens three-phase DC inverter motor to provide stable power and meet precise speed control requirements, featuring an automatic overcurrent shutdown function to protect the entire machine. The gear box further converts the motor’s speed to the screw’s speed and distributes the input torque to the two output shafts. The coupling, installed between the motor and the gear box, connects the motor’s output shaft to the gear box’s input shaft.

• The extruder hopper is a conical container made of stainless steel. It has a lid on top and a strip-shaped transparent window on the side for observing the remaining material volume.
• The bottom opening of the hopper is equipped with a rotating blade driven by an independent variable frequency motor. The feed rate is precisely adjusted by controlling its rotation speed. You can set the desired speed on the control panel, and this speed can also be linked to the screw speed.
• Depending on the material properties and process requirements, in addition to the main feed inlet, we can also add a side feed hopper in the middle or rear section of the extruder screw to add auxiliary materials such as fillers, fibers, and additives.

• Our granulating extruder comes standard with a pair of co-rotating twin screws that mesh tightly to process materials. The screw thread is made of imported alloy steel W6M05Cr4V2 with a vacuum heat-treated surface. The screw speed is controllable, up to 300 RPM.
• The screw consists of different screw elements mounted on a screw mandrel. Specific materials require specific screws, allowing for the determination of different sections such as conveying, plasticizing, homogenizing, extrusion, and melting based on the different materials being produced.

• The extruder barrel consists of 5 segments, each 120mm long. The barrel material is 38CrMoAlA steel, treated with nitriding. The barrel is surrounded by a stainless steel protective cover to reduce heat loss and prevent burns to operators.
• A special support bracket at the bottom of the barrel helps to cushion axial displacement of the processing sections caused by thermal expansion.

• Each section of the barrel and the die head area are equipped with electrically heated cast aluminum heaters for heating and maintaining the material temperature, up to 300 degrees Celsius, meeting the melting requirements of most materials.
• The barrel is equipped with water cooling pipes to cool the processing sections when needed. The water pipes mainly consist of inlet pipe, return pipe, branch pipes connecting to the barrels, valves, etc. The water inlet and outlet of the first barrel section are controlled manually by valves, while the water inlet and outlet of other sections are controlled by solenoid valves. Automatic water intake for cooling is activated in case of overheating. You can connect the machine to a tap water circulation cooling system, or you can opt for a separate water circulation system for cooling.

• The vacuum exhaust port is located in the fourth section of the barrel and mainly consists of an exhaust chamber, a vacuum pump, and a condenser. Its primary function is to remove air and volatiles such as moisture and toxic gases generated during the plasticizing process in the screw.
• The built-in vacuum pump, located at the bottom of the machine, draws these volatiles into a sealed water tank. These volatiles dissolve in water and are not directly released into the air, thus purifying the laboratory environment, reducing air bubbles, and improving the quality of plasticizing. The machine is equipped with a vacuum gauge to allow you to monitor the operating status and vacuum level of the exhaust system in real time.

• The die head is mounted at the very end of the extruder barrel. Its front end is equipped with a pressure sensor to monitor the pressure of the melt before extrusion.
• The die head has circular holes of a specified size through which the melt is extruded into strips. The number of holes can be selected according to processing needs; generally, there are two, three, four, or more.

• Our extrusion pelletizing system comes standard with a Siemens PLC-supported touchscreen controller. The screen displays a dynamic simulation of the machine’s operation, showing the real-time temperature and operating status of each zone of the barrel. Various virtual buttons are also provided to allow you to set parameters such as screw speed and issue various operating commands such as heating, cooling, screw start, and blower start.
• The touchscreen supports both Chinese and English operating languages and can store a large number of test recipes.

• The equipment is equipped with an independent 304 stainless steel cooling basin located in the rear of the extruder. After exiting the die, the extrudate is drawn into the basin in a strip-like shape for cooling and shaping. Multiple guide rollers within the basin ensure the strip is fully submerged and travels along a predetermined path.
• The upper part of the basin has inlet and outlet ports at the same level. When needed, a water supply pipe can be connected to achieve dynamic water circulation, ensuring the cooling water temperature remains consistently low during machine operation.

• A silent blower is installed in the space at the bottom of the water basin. The blower’s power can be selected as needed.
• The powerful airflow from the blower is carried through a duct to the end of the basin and blows vertically downwards onto the strands that have just come out of the water. The water on the strips is quickly dried, preparing them for the next stage.

• The pelletizer is the final station in the extrusion pelletizing line. The cooled extruded strands are fed into its traction device, where a rotating tungsten carbide cutter continuously and rapidly cuts the strands into small cylindrical pellets. The cutting length and speed are adjustable. A motor at the bottom of the pelletizer provides power, and a feeding and guiding system is installed at the top. The driven traction roller rotates the cutter and stationary blade, which are directly driven by a V-belt via the gearbox output shaft to perform pelletizing.
• The pelletizer is equipped with an independent control panel to control the machine’s start/stop and pelletizing speed.

Water-cooled granulating machine

Air-cooled granulating machine

Underwater granulating machine