Determine the heating temperature and feeding speed of the plastic granulator need to consider a number of factors, the following are some common methods and reference basis:
1. Types and characteristics of plastics
Different plastics have different melting points and thermal stability. For example, the melting point of polyethylene (PE) is usually between 100-130 °C, and the melting point of polystyrene (PS) is about 240°C. You can consult the relevant plastic materials manual or technical data provided by the supplier to obtain the recommended processing temperature range for a particular plastic.
For some modified plastics or plastics with additives, the processing temperature may be different.
2. Product requirements
If there are specific performance requirements for the plastic particles after granulation, such as crystallinity, transparency, strength, etc., this will also affect the choice of heating temperature. Generally, higher temperatures can make plastics plasticize better, but may affect some properties.
3. Device features
Different models and manufacturers of pelletizer, its heating system performance and heat transfer efficiency may be different. Some devices have good heating uniformity and may require relatively low temperatures; Some devices may require higher temperatures to achieve the same plasticizing effect.
4. Experiment and experience
Small scale test is an effective way to determine the appropriate heating temperature. Start with a wide temperature range and gradually adjust to observe the plasticization of plastics, particle quality and production efficiency to find the best temperature. At the same time, it is also important to accumulate previous production experience.
1. Capacity of granulator
First understand the rated capacity of the granulator, which is an upper limit for determining the feeding speed. Generally, the maximum processing capacity of the equipment should not be exceeded.
2. Screw design and speed
The structure of the screw (such as pitch, depth, etc.) and speed will affect the conveying and plasticizing ability of the material. Usually, a higher screw speed can match a higher feeding speed, but also consider the plasticizing effect of the plastic and the load of the equipment.
3. Properties of plastics
The fluidity and viscosity of the plastic will affect the feeding rate. For example, good flow of plastic can appropriately increase the feeding speed; The more viscous plastics require a slower feeding rate to ensure adequate plasticization.
4. Product quality requirements
If the requirements for particle size uniformity, appearance quality, etc., are high, it may be necessary to appropriately reduce the feeding speed to ensure that the plastic has enough time to mix and plasticize in the barrel.
5. Observe and adjust
In the production process, observe the main machine current, discharge and particle quality. If the main current is too large, it indicates that the load is too heavy, and the feeding speed may need to be reduced; If the discharge is uneven or the particle quality is poor, it is also necessary to adjust the feeding speed.
For example, for common polyethylene plastic granulation, if an ordinary single-screw granulator is used, the initial heating temperature can be set at about 160-180 °C, and then fine-tuned according to the actual plasticization. The feeding speed can be started from a lower level, such as 50-100 kg per hour, and then gradually increased according to the operating status of the equipment and the quality of the product.
In short, determining the heating temperature and feeding speed of the plastic granulator requires comprehensive consideration of various factors, and continuous optimization and adjustment through testing and actual production observation.
