We are Specialist in custom injection molding, plastic and insert molding and over-molding of tight-tolerance, and precision components using engineering-grade resins. We manufacture wide range of molded components and assemblies for Engineering and various other Industries.  We are equipped with various Injection Molding Machines and Vertical manual molding machine, which makes us the leading molding company.
 

Injection Molding is a manufacturing technique for making parts from thermoplastic material. Molten plastic is injected at high pressure into a mold, which is the inverse of the product's shape. The mold is made by a mold maker from metal, usually either steel or aluminium and precision-machined to form the features of the desired part. Injection moulding is widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars. Injection Molding is the most common method of production, with some commonly made items including bottle caps and outdoor furniture.
 

The most commonly used thermoplastic materials are polystyrene, ABS or polystyrene acrylonitrile butadiene styrene, nylon, polypropylene, polyethylene and polyvinyl chloride or PVC.
 

Resin pellets are poured into the Feed hopper, a large open bottomed container, which feeds the granules down to the screw. The screw is rotated by a motor, feeding pellets up the screw's grooves. The depth of the screw flights decreases towards the end of the screw nearest the mold. As the screw rotates, the pellets are moved forward in the screw and they undergo extreme pressure and friction which generates most of the heat needed to melt the pellets. Heaters on either side of the screw assist in the heating and temperature control during the melting process.

The hydraulic System pumps oil to firmly close the male and female mold parts. The liquid resin is then injected into the mould. The molds are clamped shut by hydraulics, and the heated plastic is forced by the pressure of the injection screw to take the shape of the mold. Some machines are run by electric motors instead of hydraulics or a combination of both. The water-cooling channels then assist in cooling the mould and the heated plastic solidifies into the part. Improper cooling can result in distorted moulding or one that is burnt. The cycle is completed when the mold opens and the part is ejected with the assistance of ejector pins within the mould. These ejector marks are sometimes visible as slightly indented circles on a plastic part.
 

Considerable thought is put into the design of moulded parts and their moulds, to ensure that the parts will not be trapped in the mould, that the moulds can be completely filled before the molten resin solidifies, to compensate for material shrinkage, and to minimize imperfections in the parts.

Moulds separate into at least two halves (called the core and the cavity) to permit the part to be extracted. In general the shape of a part must not cause it to be locked into the mould. For example, sides of objects typically cannot be parallel with the direction of draw (the direction in which the core and cavity separate from each other). They are angled slightly (draft), and examination of most plastic household objects will reveal this. Parts that are "bucket-like" tend to shrink onto the core while cooling, and after the cavity is pulled away, are ejected using pins. Parts can be easily welded together after moulding to allow for a hollow part that couldn’t physically be designed as one mould.

More complex parts are formed using more complex moulds, which may have moveable sections called slides which are inserted into the mould to form features that cannot be formed using only a core and a cavity. Slides are then withdrawn to allow the part to be released. Some moulds allow previously moulded parts to be reinserted to allow a new plastic layer to form around the first part. This system can allow for production of fully tyred wheels.

The core and cavity, along with injection and cooling hoses form the mould tool. While large tools are very heavy, they can be hoisted into moulding machines for production and removed when moulding is complete or the tool needs repairing or polishing. The resin, or raw material for injection moulding, is usually in pellet or granule form, and is melted by heat and shearing forces shortly before being injected into the mould. The channels through which the plastic flows toward the chamber will also solidify, forming an attached frame. This frame is composed of the sprue, which is the main channel from the reservoir of molten resin, parallel with the direction of draw, and runners, which are perpendicular to the direction of draw, and are used to convey molten resin to the gate(s), or point(s) of injection. The sprue and runner system can be cut or twisted off and recycled, sometimes being granulated next to the mould machine. Some moulds are designed so that the part is automatically stripped through action of the mould.

The quality of the moulded part depends on the quality of the mould, the care taken during the moulding process, and design details of the part itself. It is essential that the molten resin be at just the right pressure and temperature, so that it flows easily throughout the mould. The parts of the mould must join precisely lest leakage of molten plastic form, a condition known as flash, requiring extra labour to trim by hand. When filling a new or unfamiliar mould for the first time, where shot size for that mould is unknown, a technician should reduce the shot size and nozzle pressure so that the mould fills 90-95%, creating a "short shot". Then, using that known shot volume, pressure can be raised without fear of damaging the mould. Sometimes factors such as venting, temperature, and resin moisture content can cause flash formation as well.

Other common problems with plastics moulded by injection include surface defects, short shots, stress lines, flow lines, and silvering. The latter is caused by moisture in the resin and can be alleviated by keeping raw material in dry or by drying it in an oven before use.

Traditionally, moulds have been expensive to manufacture. They were usually only used in mass production where thousands of parts were being produced. Moulds are typically constructed from hardened steel or aluminium. The choice of material to build a mould is primarily one of economics. Steel moulds generally cost more to construct, but their longer lifespan will offset the higher initial cost over a higher number of parts made before wearing out. Aluminium moulds can cost substantially less, and when designed and machined with modern computerized equipment, can be economical for moulding hundreds or even tens of thousands of parts.

The EDM (Electric Discharge Machining) or spark erosion process has become widely used in mould making. As well as allowing the formation of shapes which are difficult to machine, the process allows pre-hardened moulds to be shaped so that no heat treatment is required. Changes to a hardened mould by conventional drilling and milling normally require annealing to soften the steel, followed by heat treatment to harden it again. EDM is a simple process in which a shaped electrode, usually made of copper or graphite, is very slowly lowered onto the mould surface (over a period of many hours), which is immersed in parafin oil. A voltage applied between tool and mould causes erosion of the mould surface in the inverse shape of the electrode.