Compound machine

A reactive polymer (RP) is simply a device to alloy different materials by changing their molecular structure inside a compounding machine. True reactive alloying induces an interaction between different phases of an incompatible mixture and assures the stability of the mixture s morphology. The concept is not new. This technology is now capable of producing thousands of new compounds to meet specific design requirements. 

The melt-fed extruder is typically designed with a relatively short barrel length of 6 to 1L/D. Since the resin is molten when it enters the extruder, the motor size is relatively small compared to a plasticating extruder with the same barrel diameter. The extruders are typically starve-fed. That is, the extruder is operating at a screw speed that is higher than required, and thus the rate is not controlled by the screw speed, instead, the rate of the overall process is controlled by the feedstock addition rate to the compounding machine. 

Today, basically every compounding machine is fitted with at least one degassing zone to remove moisture, air, and/or decomposition products. These components are introduced either with the polymer or additives or may be released during the compounding process. A high level of low-molecular substances can decrease mechanical properties and can lead to subsequent degassing by diffusion which runs counter to the demand for odor- and taste-free finished products. 

Compound machine—A machine consisting of two or more simple machines. 

Overload capacities of impulse turbines are very high. Additional nozzles may be used, or in compound machines steam at boiler pressure may be admitted to the secondary nozzles. 

Co-rotating twin screw extruders are the dominant tjqie of compounding machines. A broad variety of compounding tasks can be executed efficiently [790]. The main advantages of this type of machine are the following [730] ... 

During the last few years several attempts were made to develop mathematical models capable of describing the morphology evolution during blending in different model flows and compounding machines. These efforts are summarized in Table 9.7, and briefly discussed below under separated headings. 

There are twelve criteria for the economic, high-quality compounding 1) sound fundamental design principles of the compounding machine 2) flexibility of operation 3) high screw torque ... 

Compound machines are two or more simple machines working together. A wheelbarrow is an example of a complex machine. It uses a lever and a wheel and axle. Machines of all types ease workload by changing the size or direction of an applied force. The amount of effort saved when using simple or complex machines is called mechanical advantage or MA. 

A simple machine is a basic device used to make work easier. Work is the transfer of energy from one physical system to another. During this process, energy is not created, only transferred. There are six simple machines inclined plane, wedge, screw, lever, wheel and axle, and pulley. We discuss each simple machine separately in this chapter. If we combine two or more simple machines so that they function together to make work easier, the device is called a compound machine. A wheelbarrow is an example of a compound machine it incorporates two simple machines (the lever and the wheel and axle). 

Two or more simple machines used together become a compound machine. 

Simple machine Compound machine Mechanical advantage... 

Dry blending may be used to produce pellets by melt compounding. Machines of single- or twin-screw extruders are normally used. The pellets produced from compounding are processed by conventional routes such as extrusion, calendering or injection moulding. 

Sound fundamental design principles of the compounding machine... 

Figure 6.20 Injection machine for thermosetting plastics, available with screw or granular materials or plunger for bulk molding compounds. Machine also has an integral Rollaveyor tumble-blast deflasher inside the housing to deliver deflashed parts on a conveyor out through open end at left. Courtesy of Hull Corporation.)...

The several techniques available to produce filled polymer materials vary greatly in their methods and results. Extensive experience with pre-compounded glass-reinforced polymers reveals that the physical properties of the product vary significantly (Table 5.2) with various compounding techniques [16-19]. What one should look for in a compounding machine and what one should consider when setting up a compounding operation are very important to understand. 

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