1. Flush the cooling channel with acid
The water-cooled extruder barrel is actually a heat exchanger. Like all heat exchangers, the water channel is prone to fouling and deterioration. Many operators have noticed that the cooling performance of a new extruder is much better than that of a three or four-year extruder. The old machine has a layer of scale attached to the inner surface of the water channel, which affects the heat transfer efficiency. Using a certain concentration of acid to clean the barrel can clean up the scale and maintain the good heat transfer effect of the barrel.
2. Use synthetic gear oil
The gear box is the heart of the twin screw extruder. Therefore, we need to prevent gearbox problems, and use synthetic gear oil to better protect the gears.
Synthetic gear oil concerns:
More slippery, resulting in less friction;
Gears, bearings and seals will last longer;
Gear running temperature is lower and quieter;
Synthetic oil does not lose viscosity due to machine shear;
It maintains a high viscosity at high temperatures.
3. Clean the machine often
The purpose of the cleaning machine is to remove the residual materials in the extruder and die, which avoids time-consuming disassembly and cleaning. Cleaning materials are often divided into two categories: chemical cleaning agents and mechanical friction cleaning agents. Many cleaning agents have both chemical and frictional functions. Chemical cleaning agents will react with plastic residues to remove them from the mechanical surface.
The principle of mechanical friction cleaning is to rub and wash away residual material from the metal surface, using friction and shearing methods. The processor can find suitable cleaning materials and methods through many trials. No cleaning material has a cleaning effect on all materials. Processors need to clean materials cheaply and efficiently. For example, many operators in the Midwestern United States use corn as a material for cleaning machines because it is easily available and has a good cleaning effect on the machine.
1. The correct way to switch colors and materials
People who squeeze out always want to drive the machine longer. But in reality, due to customer demand, we often need to constantly switch, produce 80 kg of product A, and then produce 200 kg of product B, and so on.
1. The batch of products should correspond to the size of the machine. This seems to be self-evident. However, many processors had no plans to produce 500 pounds of orders on a 75 machine, resulting in 300 pounds of waste.
2. Write the procedures for cleaning or disassembling each product. This helps operators plan their time and eliminate their disputes about how much material will be produced.
3. Help the operator to place clean operating tools around the extruder. If the material is changed frequently, build a workbench around the extruder to prepare everything needed.
4. Study the flow of raw materials and finished products into and out of the operation site. It is arranged so that the operator spends less energy on the mobile transportation.
5. Remove the requirements for the cleanliness of the machine for the next product. If you know that the next product requires a thorough manual cleaning machine, then don't waste time and materials to confuse the machine.
6. If possible, schedule production in the order of reducing cleaning machines. This means going from light to dark. On the contrary, you have to disassemble the machine multiple times.
2. The correct way to start and stop the extruder
Common operation methods:
Operators are used to leaving the extruder on when they arrive at the factory in the morning, but they go to work on other things. Allow the extruder to heat to full scale and leave it idle for several hours. Doing so will cause the polymer to adhere to the screw and barrel, and then these polymer materials will continue to degrade and char. The cleaning machine cannot remove these materials. What's worse is that once the machine produces products, black spots will periodically run out of the screw and barrel, contaminating the product, and causing customer complaints.
The correct boot method:
Plan when to actually operate the extruder, and then start heating, as long as the temperature reaches a predetermined value, and then the barrel is filled.
The correct shutdown method:
Before shutting down, fill the extruder with inert polymer (such as HDPE) to the maximum extent to seal the gap of the machine. HDPE drives away oxygen and coats the metal surface, greatly reducing the formation of carbon oxides. After the extruder is "sealed", it is better to chill the extruder rather than leave it in air for 18 hours. The so-called rapid cooling is to set all temperatures to zero and open all cooling water valves. Turn on the cooling water pump to let the cooling water pass through all the cylinder parts to quickly cool down. The rapid cooling will avoid polymer degradation and carbonization.
