【1】 Precautions for using paraffin forming machine
The paraffin forming machine should run in a forward direction; Avoid reversing. It is prohibited to operate the empty machine without load, and the hot machine should be operated with feeding to avoid sticking the shaft. It is strictly prohibited to enter iron objects and other debris into the inlet and vent holes of the paraffin forming machine. To avoid accidents and affect normal production. Below we will introduce the precautions when using the paraffin forming machine.
1. Before starting up, heat up for about forty to fifty minutes. Raise the temperature to the point where you can pull the triangular belt of the motor by hand until it is free; Pull continuously in the normal working direction eight to ten times. Then continue to heat up for about ten minutes, and then turn on the machine, but continue to heat up because normal production requires continuous heat supplementation, and adjust the temperature according to different properties.
2. When the paraffin forming machine is working normally, the machine temperature should be kept stable and not fluctuate between high and low. Near the vent hole, the temperature of the machine head should be maintained at around 200 ℃ (referring to materials C and B).
3. The feeding should be uniform and there should be no shortage of materials. The feeding speed and feeding speed of the machine should be coordinated appropriately. Otherwise, it will affect the quality and yield of particles.
4. Always pay attention to changes in the body temperature, and when touching the strip with clean hands without touching it, immediately raise the temperature. Until the note touches hands, it is normal.
5. When the bearing part of the reducer burns or is accompanied by noise, the machine should be stopped for timely maintenance and additional oil should be added.
6. When the bearing areas at both ends of the main engine bearing room are hot, burnt or noisy, the machine should be shut down for maintenance and grease should be added. During normal operation, the bearing chamber should be lubricated with grease every 5-6 days.
7. Pay attention to understanding the operating rules of the machine; For example, the temperature and speed of the machine can be adjusted in a timely manner according to the situation.
8. When the operation of the machine body is unstable, attention should be paid to checking whether the gap between the couplings is too tight and adjusting it in a timely manner.
9. When shutting down, the host should cut off the power. The machine head screw plug (with a wrench) needs to be removed. Preheat separately before the next use.
【2】 Cooling characteristics of fully automatic paraffin forming machine
The fully automatic paraffin forming machine squeezes the melted polymer onto the template and forms strands from the mold hole, which are then cut into pellets by a rotary knife. The granular material is carried out with the water flow, and the template and knife are immersed in the water flow.
The temperature and flow rate of water during cutting depend on the shape of the generated pellets.
The pelletized water circulates under the action of pumps P801A/B (one standby) and cools in plate heat exchanger E803.
The particles and water discharged from the extruder enter the centrifugal dryer D805 to separate the particles and cutting water. After drying, the particles are sent to the vibrating screen S803 for further separation of oversized and undersized unqualified particles, and then transported to the mixing silo through the airflow conveying system PK804.
The cutting water is collected in D806 and filtered through the cutting water filter.
Use desalinated water or steam condensate as supplementary water for pelletizing.
Inject steam into D806 to heat the cutting water during driving, as it is necessary to maintain an appropriate temperature of the cutting water; Steam is filtered in F807 to remove impurities that may be carried in the system.
The mixture of PP powder, additives, and liquid peroxides (if required) enters the feed hopper 2802 of EX801. There is a filter screen installed in the feeding hopper 2802 to prevent large pieces of powder from entering the mixer. Blow the feed hopper with nitrogen gas to reduce the entrained oxygen. Blowing nitrogen is introduced from behind the filter screen, and the feed distribution is good, that is, the powder and additives are first mixed and melted in the twin-screw mixer.
PP powder enters the mixing machine from the feeding funnel into a mutually meshing co rotating screw and a 10 section cylinder with a jacket. According to functional differentiation, the screw and cylinder of the mixing machine can be divided into feeding area, plasticization area, homogenization area, boosting area, and devolatilization area.
The first section of the cylinder is the feeding area, and the main function of this screw is to transport the powder forward. In this section, the cylinder is continuously filled with cooling water to prevent blockage caused by premature melting of powder. The temperature of the cooling water entering is controlled at~45 ℃.
From the second section of the cylinder to the tenth section, the powder is compressed and sheared by the screw, thus melting and mixing, forming a uniformly mixed melt that reaches a specific temperature and enters downstream. These 9 cylinders are heated by electricity. In order to control the melt temperature, longitudinal holes are opened on the cylinder to allow pulses to enter the cooling water of the cylinder and reduce the melt temperature when the melt temperature is too high. Before driving, heat the cylinder with an electric heater to 250 ℃.
The melt comes out of the mixer and enters the combination section of the throttle valve and the start-up valve. The main task of this section is to change the opening of the throttle valve to affect the melt back pressure in the process section, thereby changing the degree of melt plasticization and specific energy consumption. The driving valve is used to discharge waste materials from the cylinder during driving. The throttle valve is driven by an electric motor with a worm gear mechanism. The throttle plate located inside the melt flow channel can change its angle, thereby changing the area of the melt flow channel and achieving the purpose of regulating the back pressure of the melt. The melt index and yield of the product vary, and the opening of the throttle valve also varies. After passing through the valve group, it enters the screen changer, where the melt enters and filters out solid pollutants.
The polymer melt is extruded and enters the cutting system through a mesh changer. The mold head distributes the melt onto 1540 templates φ 2.6mm mold hole. When the melt passes through the mold hole, it forms a strip shape. When the strip shaped melt comes out of the mold hole, it is cut into particles of length by 22 rotating cutting blades located in the cutting chamber of the underwater forming machine. The particles are immediately cooled by the cutting water in the cutting chamber. The cutting water is transported by the cutting water pump and continuously passes through the cutting water chamber.
The polymer that comes out of the cutting water has become pellets, which are dried by the D805 dryer, and then transported to the pellet buffer tank D807 by the fully automatic paraffin forming machine through the rotary valve RF802 to the D901A/B/C/D homogenization silo. After being delivered to the packaging yard for packaging and leaving the factory.
