In the modern plastic processing field, extrusion molding technology has become an indispensable and important process due to its high efficiency and continuous nature. Whether it is plastic pipes and films in daily life or the coating layers of wires and cables in the industrial field, extrusion molding plays a key role. In extrusion equipment, sensors, as the core components for precise monitoring and control, are of vital importance. They can monitor and control various parameters during the extrusion process in real time, ensuring production efficiency and product quality. (Note: Some of the pictures in this article are from the Internet. If there is any infringement, please delete them.)

 

The important role of sensors in extrusion molding

Sensors play a crucial role in the extrusion molding process, mainly reflected in the following aspects:

1. Temperature control: Temperature sensors are installed in the barrel, die head and cooling device to monitor the temperature of each part in real time, ensuring that the material melts and cools at an appropriate temperature. Through precise temperature control, poor molding caused by overheating and decomposition of materials or insufficient cooling can be avoided.

2. Pressure monitoring: Pressure sensors are used to monitor the pressure inside the screw and die head, ensuring that the material maintains a stable pressure during the extrusion process. The feedback information from the pressure sensor can help adjust the screw speed and feeding rate, avoiding product defects caused by pressure fluctuations.

3. Material flow monitoring: The flow sensor can monitor the conveying speed and flow rate of the material in real time to ensure that the material enters the extruder evenly and stably. This is crucial for ensuring the consistency of product quality.

4. Cooling water temperature control: The temperature sensor installed in the cooling water tank can monitor the temperature of the cooling water to ensure stable cooling effect. The cooling and shaping process of the product can be optimized by automatically adjusting the temperature and flow rate of the cooling water.

Through real-time monitoring and feedback control by sensors, the extrusion molding process can achieve automated and intelligent production, improving product quality and production efficiency.

 

In the field of extrusion molding, GRAEFF's sensor products stand out particularly, including but not limited to the following categories:

G Series Melt pressure sensor

The GRAEFF melt pressure sensor series is made of stainless steel, while other materials are manufactured through special processes and have passed high-strength tests. This series of products have a long service life, precise measurement performance, and the zero point is less and more stable affected by temperature.

It can be used to precisely measure the melt pressure, ensuring the stability of the extrusion process and avoiding product defects caused by pressure fluctuations.

 

GT Series Temperature sensor

The temperature sensor series is particularly suitable for temperature detection of tools, heating blocks, etc. in fields such as plastic technology, pharmaceutical industry, power plant technology, heating and cooling technology, chemical plants and mold manufacturing. This series has no restrictions on the combination of high-quality materials.

It can monitor the temperature changes inside the barrel in real time to ensure that the plastic melts at an appropriate temperature and avoid processing problems caused by excessively high or low temperatures.

 

GD Series Displacement sensor

The GD series displacement sensor, also known as the linear displacement sensor, is a linear device that belongs to metal induction. Its function is to convert various measured physical quantities into electrical quantities.

It can be used to monitor the deformation of molds, ensuring their stability under high temperature and high pressure, thereby guaranteeing the dimensional accuracy of the products.

GRAEFF, with its advanced sensor technology, provides comprehensive monitoring and control solutions for extrusion molding equipment, helping enterprises enhance production efficiency and product quality.

 

The principle of extrusion molding

Extrusion molding is a processing technique that transforms materials such as thermoplastics into a molten state through heating and mechanical shearing, and then extrude them into products of specific shapes through molds. The basic principle is to use the rotation of the screw in the extruder to heat solid plastic to a molten state, forming a viscous flow material. Then, it is extruded into shape through a die with a certain shape and cooled to solidify into the final product.

 

The equipment composition for extrusion molding

Extrusion molding equipment mainly includes the following key parts:

1. Extruder

· Feeding device: It is used to supply materials to the barrel and is usually equipped with an insulating jacket and an automatic feeding device.

· Screw and barrel: The screw provides shearing force and propulsion force through rotation, causing the material to melt and mix. The barrel provides support for the screw and heats the material.

· Heating and cooling system: The heating system is used to heat the material to a molten state, while the cooling system is used to control the temperature of the screw and barrel to ensure uniform plasticization of the material.

· Transmission system: Drives the screw to rotate and provides the required torque.

 

2. Machine head and die

· Head: It includes components such as the diverter, diverter bracket, and pipe core, which are used to adjust the flow direction of the material and the inner surface of the formed pipe.

· Die: Determines the shape and size of the extruded material.

 

3. Ancillary equipment:

· Cooling devices: such as cooling water tanks, cooling air ducts, etc., are used to cool and shape the extruded materials.

· Traction device: It is used for stretching and pulling extrudates to eliminate the expansion effect upon demolding.

· Cutting device: It is used to cut continuously extruded products into the required length.

 

The process flow of extrusion molding

The process flow of extrusion molding mainly includes the following steps:

1. Raw material preparation and pretreatment: Dry and pre-mix raw materials (such as granules, powders, etc.) to ensure they are free of impurities and moisture.

2. Feeding and plasticizing: The pre-treated raw materials are fed into the barrel of the extruder through the feeding device. Under the rotation and heating of the screw, the raw materials gradually melt and form a uniform melt.

3. Extrusion molding: Under the thrust of the screw, the molten material is extruded through the die head and die to form the desired shape of the product.

4. Cooling and shaping: The extruded material is cooled through a cooling device (such as a cooling water tank) to solidify and form.

5. Traction and Cutting: The cooled profile is stretched and pulled out through the traction device, and then cut to the required length through the cutting device.

6. Post-treatment: including heat treatment, surface treatment, etc., to enhance the dimensional stability and performance of the product.

 

Summary

Extrusion molding technology holds an important position in the field of plastic processing due to its high efficiency and continuous nature. As a key component of extrusion molding equipment, sensors ensure the stability of the production process and the consistency of product quality by real-time monitoring and controlling parameters such as temperature, pressure and flow rate. GRAEFF's sensor products, with their high precision and reliability, provide strong technical support for the extrusion molding process, helping enterprises achieve automated and intelligent production.