Plastic HDPE Injection Molding Process Settings Heating temperature: Barrel temperature feeding zone 30～50°C (50°C) Zone 1 160 ~ 250 ° C (200 ° C) Zone 2 200 ~ 300 ° C (210 ° C) Zone 3 220 ~ 300 ° C (230 ° C) Zone 4 220 ~ 300 ° C (240 ° C) District 5 220 ~ 300 ° C (240 ° C) Nozzle 220 ~ 300 ° C (240 ° C) The temperature in parentheses is recommended as the basic set value, the stroke utilization is 35% and 65%, and the ratio of module flow length to wall thickness is 50:1 to 100:1. Melt temperature: 220 ~ 280 ° C Barrel constant temperature: 220 ° C Mold temperature: 20 ~ 60 ° C Injection pressure: has good flow performance, avoiding excessive injection pressure of 80 ~ 140MPa (800 ~ 1400bar); Except for some thin-walled packaging containers, it can reach 180MPa (1800bar) Holding pressure: high shrinkage, it takes a long time to hold the product, dimensional accuracy is the key factor, about 30% to 60% of the injection pressure
Read more →The injection molding process refers to a process of producing a semi-finished part of a certain shape by pressing, injecting, cooling, and detaching the molten raw material. The injection molding process of plastic parts mainly includes six stages of clamping–filling—gas-assisted, water-assisted pressure-cooling-opening—release. 1. Filling stage Filling is the first step in the entire injection molding cycle, from the time the mold is closed to the injection, until the mold cavity is filled to approximately 95%. In theory, the shorter the filling time, the higher the molding efficiency; but in actual production, the molding time (or injection speed) is subject to many conditions. High speed filling. When the high-speed filling is performed, the shear rate is high, and the plastic has a viscosity drop due to shear thinning, so that the overall flow resistance is lowered; the local viscous heating effect also makes the thickness of the solidified layer thin. Therefore, in the flow control phase, the filling behavior often depends on the volume to be filled. That is, in the flow control stage, due to the high-speed filling, the shear
Read more →POM is an abbreviation for polyoxymethylene, and POM belonging to organic chemistry is a high density polymer. Therefore, POM is also known as cold steel, and POM is also called special steel. POM is a high-density, high-crystallization thermoplastic engineering plastic. POM has good physical, mechanical and chemical properties. POM also has a prominent feature, that is, POM has intentional friction resistance. What is the overall performance of POM? Below list the characteristics of POM plastic: 1, POM has a very low coefficient of friction and geometric stability, POM plastic is particularly suitable for the production of gears and bearings. 2, POM has high temperature resistance, so POM is also used in pipeline devices. 3, POM is a tough and elastic material, POM still has good creep resistance even at low temperatures, POM has good geometric stability and impact resistance. 4, the high degree of crystallization of POM leads to its high shrinkage, POM plastic can reach 2% to 3.5%. POM has different shrinkage rates for a variety of different reinforced materials. POM is a crystalline plastic. The melting point of
Read more →Plastic Injection Molding Process Parameters have 5 big parts: Injection Pressure,Injection Time,Injection temperature,Dwell Pressure and Dwell Time, Dwell Pressure and Dwell Time. They are all very important setting for injection molding engineers. 1. Injection Pressure Injection pressure is provided by the hydraulic system of the injection molding system. The pressure of the hydraulic cylinder is transmitted to the plastic melt through the screw of the injection molding machine. Under the pressure push, the plastic melt enters the vertical flow path of the mold through the nozzle of the injection molding machine (also the mainstream channel for some molds), the main flow channel, and the split flow. The process, through the gate into the mold cavity, is the injection molding process, or the filling process. The pressure is present to overcome the resistance during the melt flow, or conversely, the resistance present during the flow process needs to be offset by the pressure of the injection molding machine to ensure a smooth filling process. During the injection molding process, the pressure at the nozzle of the injection molding machine is highest
Read more →Abstract: Optimal design of plastic injection molding parameters are discussed concerning preheating temperature, stove temperature, mold temperature, pressure oil temperature, clamping force, mold filling speed, filling pressure, dwell time, dwell presure, screw speed, pressure reliefback pressure. Norial problems and quality faults in plastic injection are also analyzed in detail. Injection molding refers to an operation process in which a resin is heated and melted, uniformly mixed with other additives, and then injected into a mold to be cooled and solidified to obtain a product having a desired shape. In order to allow the molten material to sufficiently flow into the corners of the mold cavity to obtain a product having a full shape, no wrinkles on the surface, and no voids inside, it is necessary to apply a high pressure to the melt at the time of molding. For a certain plastic parts, when the appropriate plastic varieties, molding methods and equipment are selected, and the reasonable molding process and mold structure are designed, in the production, the selection and control of the process conditions is to ensure the smooth
Read more →Styrene acrylonitrile (SAN) has good rigidity, strength, and toughness, and better chemical resistance than polystyrene. Typical Applications of Styrene acrylonitrile (SAN) Electrical – receptacles – mixer bowls – housings – refrigerator fittings – chassis for television sets – cassette boxes Automotive – head lamp bodies – reflectors – glove compartments – instrument panel covers Household applications – tableware – cutlery – beakers Plastic SAN Injection Molding Processing Conditions Gates of SAN Injection Mold All conventional gate types may be used. Chemical and Physical Properties of Styrene acrylonitrile (SAN) SAN copolymers are produced by the polymerization reaction of styrene and acrylonitrile. They are strong, transparent materials. The styrene component imparts clarity, stiffness, and processibility and the acrylonitrile component imparts chemical and thermal resistance. They have excellent load bearing capacity, rigidity, good resistance to chemicals, heat deformation, and cyclic temperature loads, and dimensional stability. The properties are dependent on the acrylonitrile content and commercial grades offer different acrylonitrile molecular masses. The addition of glass fibers enhances rigidity and resistance to heat deformation, and decreases the coefficient of linear thermal expansion. The Vicat
Read more →Polystyrene (PS) is an inexpensive and hard polymer that is used extensively. Typical Applications of Polystyrene (PS) Packaging Housewares – tableware – trays Electrical – transparent housings – light diffusers – insulating film Plastic PS Injection Molding Processing Conditions Runners and Gates of PS Injection Mold All types of conventional gates can be used. Chemical and Physical Properties of Polystyrene (PS) General-purpose PS is produced by the polymerization of styrene. Most commercial grades are clear, amorphous polymers. PS offers excellent dimensional and thermal stability, optical clarity, and very little tendency to absorb moisture. It has good dielectric properties. It is resistant to water and dilute inorganic acids, but is attacked by strong oxidizing acids such as concentrated sulfuric acid, and is swollen by some organic solvents. Processing shrinkage is typically between 0.4–0.7%.
Read more →Polyphenylene ether blends (PPE or PPO) are engineering thermoplastics that exhibit resistance to high temperatures. Because of the high glass transition temperature, which is about 210°C, PPEs are often blended with other polymers to increase processability. Typical Applications of Polyphenylene ether blends (PPE or PPO) household appliances – dishwasher – washing machine electrical applications – control housings – fiber-optic connectors Plastic PPE Injection Molding Processing Conditions Runners and Gates of PPE Injection Mold All gates can be used; tab and fan gates are preferred Chemical and Physical Properties of Polyphenylene ether blends (PPE or PPO) PPO is poly(2,6 dimethyl p-phenylene) oxide. The ether linkages offer easier processibility. Copolymers are referred to as PPEs (Polyphenylene Ethers). Typically, the commercially available PPOs (or PPEs) are blended with other thermoplastic materials such as PS (or HIPS), Nylon, etc. These blends are still referred to as PPOs or PPEs. The blends offer superior processibility compared to pure PPOs. Their viscosities are lower. A range of properties can be obtained depending on the ratios of PPO and PS. Blends with nylons (PA 6/6) offer improved
Read more →Polypropylene (PP) is a widely-used, translucent, semicrystalline, thermoplastic polymer with excellent chemical resistance to a range of chemicals. Typical Applications of Polypropylene (PP) Automotive (mineral-filled PP is often used) – dashboard components – ductwork – fans – some under-hood components Appliances – dishwasher door liners – dryer ductwork – wash racks – clothes washer lids – refrigerator liners Consumer products – lawn/garden furniture – lawn mower components – sprinklers Plastic PP Injection Molding Processing Conditions Runners and Gates of PP Injection Mold In the case of cold runners, typical diameters range from 4–7 mm. Full round sprues and runners are recommended. All types of gates can be used. Typical pin gate diameters range from 1–1.5 mm, but diameters as low as 0.7 mm can be used. In the case of edge gating, the minimum gate depth should be half the wall thickness and the width should be at least double the thickness. Hot runners can readily be used for molding PP. Chemical and Physical Properties of Polypropylene (PP) PP is produced by the polymerization of propylene using stereospecific catalysts. Isotactic
Read more →Polyacetal or polyoxymethylene (POM) has a low coefficient of friction, good dimensional stability, and high-temperature resistance. Applications of polyoxymethylene (POM) gears bearings valve and pump housings lawn equipment Plastic POM Injection Molding Processing Conditions Runners and Gates of polyoxymethylene (POM) Any type of gate can be used. Circular tapered gates should be as short as possible. Insulated, hot tip runners are preferred for homopolymers. Both internally and externally heated hot runners can be used with copolymers. Chemical and Physical Properties of polyoxymethylene (POM) Acetals are tough, resilient materials that exhibit good creep resistance, dimensional stability, and impact resistance even at low temperatures. Acetal grades are either homopolymers or copolymers. Homopolymers have better tensile strength, fatigue resistance and hardness, but are difficult to process. Copolymers have better thermal stability, chemical resistance, and processibility. Both homopolymers and copolymers are crystalline and have low moisture absorption. Copolymers can be used continuously at air temperatures up to 100°C [212°F]. Homopolymers have slightly higher temperature resistance. The many grades of acetal materials that are available can be tailored for different applications. High crystallinity levels of
Read more →Polymethyl methacrylate (PMMA) has excellent chemical and weather resistance. Typical Applications of Polymethyl methacrylate (PMMA) Automotive – signal light devices – instrument panels Blood cuvettes Industrial – video discs – lighting diffusers – display shelving Consumer – drinking tumblers – stationery accessories Plastic PMMA Injection Molding Processing Conditions Chemical and Physical Properties of Polymethyl methacrylate (PMMA) Pellets for injection molding are made by bulk polymerization of methyl methacrylate followed by extrusion and pelletization, or by polymerization in an extruder. Formulations vary by molecular weight and physical properties such as flow rate, heat resistance, and toughness. Higher molecular weight grades are tougher than lower molecular weight grades. High flow formulations are generally preferred for molding. Heat deflection temperature under load varies from 75°C [167°F] for high flow materials to 100°C [212°F] for low flow (high molecular weight) materials. PMMA has excellent optical properties and weatherability. The white light transmittance is as high as 92%. Molded parts can have very low birefringence, which makes PMMA suitable as a material for video discs. PMMA exhibits room temperature creep. The initial tensile strength is
Read more →Glycol-modified PET and copolyesters (PETG) offer a desirable combination of properties such as clarity, toughness, and stiffness. Typical Applications of Glycol-modified PET and copolyesters (PETG) – medical devices – test tubes bottles toys displays and lighting fixtures face shields refrigerator crisper pans Plastic PETG Injection Molding Processing Conditions Chemical and Physical Properties Glycol-modified PET and copolyesters (PETG) PETGs (or copolyesters) are glycol-modified PETs. The modification is achieved by adding a second glycol during polymerization. The resulting molecular structure is irregular and the material is clear and amorphous with a glass transition temperature of 88°C [190°F]. PETGs can be processed over a wider processing range than conventional PETs and offer a good combination of properties such as toughness, clarity, and stiffness. Feel Free to Contact Us if Any Questions
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