Know about injection moulding copy

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Know How about Plastic Injection Moulding1Bhushan L. GadiloharCell : 9890475326Email : [email protected]

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PlasticsWhat does the word Plastic mean?The word Plastic means easily Shaped or Moulded.2Plastic :: A polymeric substance of large molecular weight. Polymer :: A substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together, e.g., many synthetic organic materials used as plastics and resins.

3Why do we use plastics?Think of five reasons why we use plastics.

Plastics can be Shaped into very complex shapes.

Plastics are Soft to the touch.Plastics are available in a large range of Colours.Plastics are Tough and durable.Plastics are Light in weight.Plastics are Strong.Plastics can be shaped Easily, Quickly and Cheaply.

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Plastics play a very important role in our lives and the products we use every day.

PlasticsThermoset Plastics - material, which when heated, is pressed or moulded into a shape. The heating process changes the structure of these materials, and for this reason they cannot by re-cyclable. There are two main groups of plastics:5Thermo Plastics - A material that can be heated and cooled repeatedly without changing the material structure. Highly recyclable. HeatCoolHarden

Soften

HeatCoolHarden

Soften

Burn

Ex. ABS, PC , PS, PVC, PP, LDPE, HDPE, Nylon etc.Ex. PF, MF, Epoxy resin etc.

Types of Moulding6Injection moulding - Well suited for high-quality, high-volume part manufacturingInjection moulding is by far the most versatile of all injection moulding techniques. Blow Moulding Well suited for hollow objects, like bottles The process follows the basic steps found in glass blowing. A parison (heated plastic mass, generally a tube) is inflated by air. The air pushes the plastic against the mould to form the desired shape. Once cooled, the plastic is ejected. Extrusion Moulding Well suited for long hollow formed applications like tubing, pipes and straws While other forms of moulding uses extrusion to get the plastic resins into a mould, this process extrudes the melted plastic directly into a die. The die shape, not a mould, determines the shape of the final product. The extruded tubing is cooled and can be cut or rolled for shipment.

Types of Moulding7Rotational Moulding Well suited for large, hollow, one-piece parts like Water tanks. This process uses high temperatures and rotational movement to coat the inside of the mould and form the part. The constant rotation of the mold creates centrifugal force forming even-walled products. Because it is ideally suited to large hollow containers, such as tanks, it is not a fast moving process. Compression Moulding Well suited for larger objects like auto parts The name of this moulding method says everything. A heated plastic material is placed in a heated mould and is then compressed into shape. The plastic can be in bulk but often comes in sheets. The heating process, called curing, insures the final part will maintain its integrity. This method of moulding is very suitable to high-strength compounds like thermosetting resins as well as fiberglass and reinforced plastics.

Plastic Injection Moulding8Injection moulding :: A manufacturing process in which melted plastic is injected into a mould to form a part. The first injection moulding machine was invented and patented by brothers John and Isaiah Hyatt in 1872. Today, the process is more complicated although, the basic principle of plastic being injected into a waiting mould is still the same. One of the biggest advancements has come by way of the materials used, and there are now thousands of different formulations available for making Plastic Raw materials used in the plastic injection moulding process,

Plastic Injection Moulding9Injection moulding machines are fairly simple and straightforward, consisting of a hopper where raw material is placed, a heating cylinder and an injection plunger. Moulds are typically made from steel or aluminium. Major advantages to using plastic injection moulding for the manufacture of parts include:Ability to complete high-production rates Repeatability of high tolerances Minimal finishing Wide range of materials available for specific applications Minimal material loss Injection moulding is the most common plastic moulding process and is used to create a huge variety of complex parts of different size and shape.

Basics of an Injection Moulding Machine10First, lets take a quick look at how plastic injection moulding presses are rated or classified. Often plastic injection companies will provide a moulding equipment list. It may look something like this: 50 Ton Injection Moulding Presses 100 Ton Injection Moulding Presses 150 154 Ton Injection Moulding Presses 200 Ton Injection Moulding Presses 250 Ton Injection Moulding Presses 400 Ton Injection Moulding Presses So, what does this mean? Plastic injection moulding presses are classified or rated based on tonnage, or more specifically, the clamping pressure or force. Presses can run in size from less than 5 tons of clamping pressure to over 6000 tons. The higher the press ton rating, the larger the machine.

11Second, lets figure out how much clamping force or pressure is required. Basics of an Injection Moulding MachineThere are many factors that are taken into consideration when determining the size of the press. The size of the part, the polymer being used and something called the safety factor. The safety factor is an additional numerical percentage buffer that is added to the calculation to help avoid defects in the final part. Some recommend adding 10% to allow for the safety factor. As mentioned earlier, the MFI (Melt Flow Index) of the plastic compound will also impact the pressure needed to produce the part. Many calculations include the platen size as well as the mould and part size, however, to get an estimate of the press size your project will need, we have simplified it even further. A machine rated for 60 tons can deliver 60 tons of clamping pressure. This pressure keeps the mould closed during the injection process. Too much or too little pressure can cause quality issues. Too much or too little pressure can also cause flashing, where excess material appears on the part edge.

12Injection MouldingThe plastic products are made such efficiently with the help of 4M.

Man

Machine

Material

MouldWidely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars


13Applications of Injection Moulded PartsAutomotive componentsFMCG ComponentsAerospace components Cable assemblies Computer electronics ComponentsMobile/Telephone ComponentsElectronics components InstrumentMedical & dental products Medical laboratories Equipment's Toys, hobby


149th Plastivision India 2013

15The injection machine is a machine that melt plasticize the moulding material inside the heatingcylinder and inject this into the mould tool to create the moulded product by solidifying inside it. The injection machine is constructed of a mould clamping device that opens and closes the mould tool, andInjection device that plasticize and inject the moulding material. There are several types in the injection machine, and the difference is made by how these two devices are arranged.IMM - Injection Moulding Machine


16IMM - Injection Moulding Machine

Clamping UnitInjection UnitClamping Unit Mould clamping device that opens and closes the mould tool.Injection Unit That plasticize and inject the molten material into the mould.


17Injection Moulding Machine


18Injection Moulding Mould/Tool

The mould is made from metal, usually either steel or aluminiumMould - A hollow form that plastic is injected or inserted into to manufacture a plastic part.


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Injection moulds represent the greatest expense in upfront production costs.

Raw Material (Resin)20Choosing the right material for a project is one of the most important factors in creating perfect parts. When choosing a material for a specific application, generally the least expensive material that will do the job is chosen.When searching for the right resin for the job, many factors will come into play and they all will be balanced against the cost. Factors such as dimensional stability, service temperature range, and impact strength can all cause materials to be eliminated from list of possible choices.Engineering plastics are typically chosen for their superior properties.

Granules

21ABS Raw Material PropertiesGood combination of mechanical, thermal and chemical propertiesEasy processable by injection, extrusion and vacuum formingLow cost of all engineering thermoplasticsLow continuous use temperatureHigh impact strengthHigh thermal expansionLimited weather resistancePoor solvent resistance Low water absorptionAcrylonitrile Butadiene Styrene (ABS) Electroplatable

22Feeding (Runner) system

Runner The channel system that allows the flow of the melted material to fill the part cavities. Sprue The opening feed that conveys material from the nozzle to runner system in the mould. Gate The channel into which melted plastic flows into a mould.


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Injection Moulding Process


24Injection Moulding Machine Cycle

25Injection Moulding Cycle Time


26When producing injection moulded parts, it is important to understand the common problems and defects that impact product quality.

27Common Moulding DefectsMost defects in plastic parts can be traced back to three sources:

1.The material being used to make the part 2.The processing of the material in the mould 3.The mould itself


28Moulding DefectSilver streaks Circular marks appearing where the molten plastic enters the mould cavity. This is often caused by excessive moisture in the resin.

Flow marks A wavy pattern or discoloration caused by a slow injection speed which allows the material to cool too quickly.


29Moulding DefectSink marks or shrinkage Depressions or hollows in a part that can be attributed to excessive press pressure, non-uniform heating, inadequate cooling time or part design. The amount of volume reduction that takes place when a plastic material cools. Short shot A defect where the material does not fully fill the part cavity


30Moulding DefectBurn marks Black or brown blemishes (which are carbon deposits) that are caused by improper ventilation or prolonged heating in the mould. Z

Weld line The juncture where two flow fronts meet and are unable to join together during the moulding process. These lines usually occur around holes or obstructions and cause localized weak areas in the moulded part.


31Moulding DefectFlash or burrs A thin lip or protrusion beyond the body of the part that is generally caused by poor clamping force, improper mould design and/or mould damage. Warpage A part with a distorted shape can be due to a poor cooling system in the mould. When the plastic material is cooled unevenly, the result is a bowing effect.


32Jetting A snakelike line of material that cools independently of the material around it. This defect is generally due to poor tool design often relating to incorrect gate size. Moulding Defect

Waviness - A wavelike line of material that cools, non-uniform heating, inadequate cooling time. The amount of volume reduction that takes place when a plastic material cools.


33Moulding DefectEmbedded contaminates Particles or flecks of residual foreign material that can originate in the barrel of the press. Discoloration - This can occur when the hopper and feed zone have not been flushed properly to remove any residual colour.


34Proper machine for good melting and injecting of the molten plasticThe key to success in injection moulding are to have:The proper resin to appropriate part performanceA good mould for part definition and removalProper operation for efficient moulding cycle (moulding cycle depends on the design of the mould and manufacturing parameters)


35ConclusionInjection molding is one of the most important processes for plastics and it has a very wide list of kinds of products it can produce, which makes it very versatile.


Bhushan L. GadiloharCell : 9890475326Email : [email protected] you !!36

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