Faygo Union
Making good machines, being good people.
FAYGO PLAST
Jiangsu Faygo Union Machinery Co., Ltd. is a group company with four factories, and the four branches develop and manufacture equipment for the production of plastic pipes, profiles, sheets, and recycling granulation; Beverage, daily chemical bottle blowing equipment; beverage filling equipment; AGV and other robotic automation equipment.
The equipment of Jiangsu Faygo Union Machinery Co., Ltd. has been sold to markets in the Middle East, Southeast Asia, Africa, South America and Europe, more than 170 countries around the world, and the products have gained the general affirmation and trust of the customers, such as the pipe production line of 1600mm/PE large calibre for nuclear power, which is produced by Faygo Union in co-operation with the world-famous enterprises.
Screw Combinations in the Feed Section of a Twin-screw Extruder
Faygo Union has exquisite machinery manufacturing technology. Today to share with you the ‘twin-screw extruder feed section of the screw combination’ of technical issues. Let’s learn about it!
The function of the extruder feed section is to accept material fed into the extruder inlet and to convey the solids to the melting section of the extruder. Solids conveying is a unit operation that occurs in that area of the extruder. Most plastics processes using a single screw have an overflow feed: the extruder hopper is filled with polymer or a mixture of polymer and additives.
Composition of the Screw
Each screw in a twin-screw extruder consists of a threaded element configured with a screw shaft of equal length to the extruder barrel, and the two elements must be perfectly matched for the screw to rotate freely.
The function of the feed section of the extruder is to convey the solids into the extruder without softening or melting the material, a process that will keep the solids free-flowing.
Conveying Elements
Two key measurements define a conveyor element: the length of the element itself, and the axial length of the thread that completes a full rotation around the element. The longer the thread length, the wider the channel for transporting solids. Similarly, as the thread length increases, the material moves further in a single rotation.
Conveying elements with short thread lengths, also known as ‘tight threads’, can only convey material over short distances, whereas ‘wide thread’ elements will convey material over longer distances along the length of the extruder.
Configuration of the Inlet
The design of screws in the feed zone, to collect the material falling into the inlet and conveying it quickly into the extruder, is often simplified by the use of transition elements. This eliminates sharp edges that could break or material build-up. The remainder of the feed section consists of wide-winged conveying elements that run up to the start of the melting section.
Design of Powder Inlet
Powders present a challenge for feeding, especially powders with low packing density and very small particle sizes. As the light powder falls through the feed hopper, air is carried down by the powder. The mixture of powder and air occupies a large volume, effectively blocking the feed opening, which reduces or stops the polymer feed.
In addition, the entrained air must subsequently escape from the extruder. The escaping air has only one route out of the extruder – upwards into the feed hopper. The escaping air will flow upwards into the feed hopper and may result in fluidisation of the very light powder. Suspended powder will accumulate until it falls into the inlet, and the process is repeated . Between clogged feed ports and interrupted powder feed, entrained air can cause problems such as low and fluctuating feed rates.
Minimising air entrainment and removing air from the powder is essential to maintain an economical feed rate.
Faygo Union & Suzhou Yuda has been focusing on plastic extrusion, bottle blowing and filling, robot AGV, AMR trolley, and automation transformation projects for many years. Let’s work together to make the world a better place.
