Basic Info.
Plastic Processed
All of Plastic
Product Type
Granulating Extruder
Assembly Structure
Separate Type Extruder
Engagement System
Intermeshing
Screw Channel Structure
Non Deep Screw
Computerized
Computerized
Feature
High Production Efficiency
Transport Package
Plastic Film
Specification
PP, PE, PS, ABS etc.
Product Description
Advanced extrusion system
co-rotating parallel twin-screw extrusion & Research and development of extended devices
Advantages of Dart extruders
High torque technology Leading the market
First-class compounding technology
Excellent dispersion
High pigment and additive loading levels are possible
Very simple machine operation
Long lifetime of screw and barrel parts due to specially developed screw elements
ensure maximum throughput rates with greatest possible economy and highest product quality
TYPICAL APPLICATIONS
Polyolefins
Engineering Plastics
Masterbatch
Bio Plastics
LFT Long Fiber Reinforced Thermoplastics
PVC
HFFR
Thermoplastic ElastomersExtrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed through a die of the desired cross-section. The two main advantages of this process over other manufacturing processes are its ability to create very complex cross-sections, and to work materials that are brittle, because the material only encounters compressive and shear stresses. It also forms parts with an excellent surface finish.Drawing is a similar process, which uses the tensile strength of the material to pull it through the die. This limits the amount of change which can be performed in one step, so it is limited to simpler shapes, and multiple stages are usually needed. Drawing is the main way to produce wire. Metal bars and tubes are also often drawn.Extrusion may be continuous (theoretically producing indefinitely long material) or semi-continuous (producing many pieces). The extrusion process can be done with the material hot or cold. Commonly extruded materials include metals, polymers, ceramics, concrete, modelling clay, and foodstuffs. The products of extrusion are generally called "extrudates".HDPE pipe during extrusion. The HDPE material is coming from the heater, into the die, then into the cooling tank. This Acu-Power conduit pipe is co-extruded - black inside with a thin orange jacket, to designate power cables.Also referred to as "hole flanging", hollow cavities within extruded material cannot be produced using a simple flat extrusion die, because there would be no way to support the centre barrier of the die. Instead, the die assumes the shape of a block with depth, beginning first with a shape profile that supports the center section. The die shape then internally changes along its length into the final shape, with the suspended center pieces supported from the back of the die. The material flows around the supports and fuses together to create the desired closed shape.The extrusion process in metals may also increase the strength of the material.Hot extrusion is a hot working process, which means it is done above the material's recrystallizationtemperature to keep the material from work hardening and to make it easier to push the material through the die. Most hot extrusions are done on horizontal hydraulic presses that range from 230 to 11,000 metric tons (250 to 12,130 short tons). Pressures range from 30 to 700 MPa (4,400 to 101,500 psi), therefore lubrication is required, which can be oil or graphite for lower temperature extrusions, or glass powder for higher temperature extrusions. The biggest disadvantage of this process is its cost for machinery and its upkeep. Cold extrusion
Cold extrusion is done at room temperature or near room temperature. The advantages of this over hot extrusion are the lack of oxidation, higher strength due to cold working, closer tolerances, better surface finish, and fast extrusion speeds if the material is subject to hot shortness.Materials that are commonly cold extruded include: lead, tin, aluminum, copper, zirconium, titanium, molybdenum, beryllium, vanadium, niobium, and steel.Examples of products produced by this process are: collapsible tubes, fire extinguisher cases, shock absorber cylinders and gear blanks.Warm extrusion
In March 1956, a US Patent was filed for "process for warm extrusion of metal." Patent US3156043 A outlines that a number of important advantages can be achieved with warm extrusion of both ferrous and non-ferrous metals and alloys if a billet to be extruded is changed in its physical properties in response to physical forces by being heated to a temperature below the critical melting point. Warm extrusion is done above room temperature, but below the recrystallization temperature of the material the temperatures ranges from 800 to 1800 °F (424 to 975 °C). It is usually used to achieve the proper balance of required forces, ductility and final extrusion properties.Friction extrusion
Main article: Friction extrusionFriction extrusion was invented at The Welding Institute in the UK and patented in 1991. It was originally intended primarily as a method for production of homogenous microstructures and particle distributions in metal matrix composite materials. Friction extrusion differs from conventional extrusion in that the charge (billet or other precursor) rotates relative to the extrusion die. An extrusion force is applied so as to push the charge against the die. In practice either the die or the charge may rotate or they may be counter-rotating. The relative rotary motion between the charge and the die has several significant effects on the process. First, the relative motion in the plane of rotation leads to large shear stresses, hence, plastic deformation in the layer of charge in contact with and near the die. This plastic deformation is dissipated by recovery and recrystallization processes leading to substantial heating of the deforming charge. Because of the deformation heating, friction extrusion does not generally require preheating of the charge by auxiliary means potentially resulting in a more energy efficient process. Second, the substantial level of plastic deformation in the region of relative rotary motion can promote solid state welding of powders or other finely divided precursors, such as flakes and chips, effectively consolidating the charge (friction consolidation) prior to extrusion.Microextrusion
Main article: MicroextrusionMicroextrusion is a microforming extrusion process performed at the submillimeter range. Like extrusion, metal is pushed through a die orifice, but the resulting product's cross section can fit through a 1mm square. Several microextrusion processes have been developed since microforming was envisioned in 1990.Forward (ram and billet move in the same direction) and backward (ram and billet move in the opposite direction) microextrusion were first introduced, with forward rod-backward cup and double cup extrusion methods developing later. Regardless of method, one of the greatest challenges of creating a successful microextrusion machine is the manufacture of the die and ram. "The small size of the die and ram, along with the stringent accuracy requirement, needs suitable manufacturing processes." Additionally, as Fu and Chan pointed out in a 2013 state-of-the-art technology review, several issues must still be resolved before microextrusion and other microforming technologies can be implemented more widely, including deformation load and defects, forming system stability, mechanical properties, and other size-related effects on the crystallite (grain) structure and boundaries.Extrusion defects
- Surface cracking occurs when the surface of an extrusion splits
. This is often caused by the extrusion temperature, friction, or speed being too high. It can also happen at lower temperatures if the extruded product temporarily sticks to the die.- Pipe - A flow pattern that draws the surface oxides and impurities to the center of the product. Such a pattern is often caused by high friction or cooling of the outer regions of the billet.
- Internal cracking - When the center of the extrusion develops cracks or voids. These cracks are attributed to a state of hydrostatic tensile stress at the centerline in the deformation zone in the die. (A similar situation to the necked region in a tensile stress specimen)
- Surface lines - When there are lines visible on the surface of the extruded profile. This depends heavily on the quality of the die production and how well the die is maintained, as some residues of the material extruded can stick to the die surface and produce the embossed lines.
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Address:
Nanjing Jiangning District 269, Jishanglu Zhougang Industrial Park, Nanjing
Business Type:
Trading Company
Business Range:
Bags, Cases & Boxes, Manufacturing & Processing Machinery, Toys
Management System Certification:
ISO 9001, ISO 20000
Company Introduction:
Our company offers variety of products which can meet your multifarious demands. We adhere to the management principles of "quality first, customer first and credit-based" since the establishment of the company and always do our best to satisfy potential needs of our customers. Our company is sincerely willing to cooperate with enterprises from all over the world in order to realize a win-win situation since the trend of economic globalization has developed with anirresistible force.
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