Practical Skills To Improve The Performance Of Twin Screw Extruders

{Twin-screw extruder} equipment maintenance and operating specifications are issues that users are generally concerned about. Today {Nanjing Kelongweier Chemical Machinery Co., Ltd.} will introduce some of these small details in detail. 

Equipment maintenance：

1. Flush the cooling water channel with acid

The water-cooled extruder barrel is actually a heat exchanger. Like all heat exchangers, the water channel is prone to scale and damage. Many adopters have noticed that the cooling performance of a new extruder is much better than that of a three or four-year extruder. The old machinery and equipment has a layer of scale sticking to the inner surface of the water channel, which interferes with the heat transfer efficiency. Cleaning the barrel with the corresponding concentration of acid can

Remove the scale and maintain the good heat transfer effect of the barrel.

2. Using synthetic gear oil

Gearbox is the core of {twin screw extruder}. Therefore, we need to avoid gearbox problems, and use synthetic gear oil to better protect the gears.

Worry points about synthetic gear oil:

More slippery, resulting in less sliding friction;

Gears, bearings and seals will last longer;

Gears run at a lower temperature and are quieter;

Synthetic oil does not lose viscosity due to shearing of machinery and equipment;

It maintains a high viscosity at high temperatures.

3. Frequently clean machinery and equipment

The purpose of the cleaning machine is to remove the residual material 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 sliding friction cleaning agents. Many cleaning agents have both chemical and sliding friction functions. Chemical cleaning agents will react with plastic residues to remove them from mechanical surfaces.

The working principle of mechanical sliding friction cleaning is to friction and wash away residual material from the metal surface, using sliding friction and shearing methods. The processor can find suitable cleaning materials and methods after several experiments. 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 machinery and equipment because it is easily available and has a good cleaning effect on machinery and equipment.

Two more effective cleaning agents are described in detail below:

1# Mixture: 50% HDPE + 50% diatomaceous earth

2# Mixture: HDPE+water+decontamination powder. The HDPE is fed into the screw at the usual speed at the melting temperature. Stir the decontamination powder with water in a bucket to form a slurry, and slowly add the slurry from the main feed port. These slurries impact, friction, and clean the screw due to foaming.

Operating specifications

1. The correct way to convert colors and materials

People who squeeze out always want to drive machinery and equipment for a longer period of time. But in practice, due to customer demand, we often need to continuously convert, produce 80 kg of product A, and then expand to produce 200 kg of product B, and so on.

1. The batch of products should correspond to the size of the machine and equipment. This seems obvious. However, many processors had no plans to produce 500 pounds of orders on a 75 machine, resulting in 300 pounds of waste.

2. Write out the procedures for cleaning or disassembling each product in the production, which is beneficial to reduce the planning time of the technical operators and reduce their disputes about how much material will be generated.

3. Help the technical operators to place clean tools around the extruder. If you need to change the material frequently, set up an operating table around the extruder to prepare everything you need.

4. Study the flow of raw materials and finished products into and out of the use site. Reasonably arrange so that the operator consumes less time and energy on the mobile transportation tool.

5. Remove the requirements of the next product on the cleanliness of machinery and equipment. If you know that the next product requires a thorough manual cleaning machine, then don't waste a lot of time and materials to confuse the machine.

6. If possible, schedule production in the order of reducing the number of cleaning machines. This means going from light to dark. On the contrary, you have to dismantle the machine multiple times.

Second, the correct way to start and stop the extruder

Common usage:

The users 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 make the polymer adhere to the screw and barrel, and then these polymer materials will continue to degrade and carbonize. The cleaning machine cannot remove these materials. What's worse is that once the machine and equipment produce the product, the black spots will periodically remove from the screw and

Running out of the barrel contaminates the product, causing users to complain.

Correct boot method:

Plan when you really want to use 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, the extruder is filled with inert polymers (such as HDPE) to seal the gaps in the machinery and equipment. HDPE drives off oxygen and coats the metal surface, greatly reducing the formation of carbon oxides. After the extruder is "sealed", it is better to quench the extruder rather than let it cool in the 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.

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