Injection molding is one of the most widely used methods for mass manufacture of items like cars, car parts, pet bottles, etc. It is a process by which material is injected into a mould used usually to manufacture small or large parts of a larger assembly. One of the most common applications of injection molding is to produce plastic housings which are used in a variety of household appliances, consumer electronics, etc. Buckets, toothbrushes, medical devices like syringes and the valves are manufactured using injection molding.
The four processes involved in an injection molding process which all together take typically between two and four minutes are:
Clamping, injection, cooling and ejection
Clamping is securing the mould before injection, typically clamping together both its halves
Injection – is injection of the material to be molded, usually melted plastic
The cooling – molten plastic begins to cool as soon as it comes in contact with the mould surface.
Ejection – after sufficient cooling, the molded part may be ejected from the molding machine.
Building the mould to utmost precision is the main task, rather than the process of molding itself. Finishing of a mould by machines can take up to 20 hours.
Benefits of Injection molding:
- Huge range of applications – some of the common products manufactured using injection molding are bearings, cams, gears, rollers, rotors, slide guides, valves, display stands, knobs, lenses, panels, automotive consoles, eyeglass frames, air filters, safety masks, aircraft components, kitchenware, drains, gutters, bushings, seals, washers and many more
- It is a very precise method.
- Allows the manufacture of complicated shapes and designs that would otherwise be difficult and time consuming to make
- Mass production of such parts is possible; high output coupled with low labor cost, easy to repeat.
- Less workload as essentially the product is ready after injection molding
- Helps recycling plastic as scrap and unused molding can be reused. Hence it can be termed as environmentally friendly
- Design can be changed by changing the mould specifications.
- The color of the product can be changed easily
- In addition to plastic, fillers can be added while molding to make the part stronger by reducing the density of plastic. Inserts can also be made available in the final product.
- Co-injection molding is possible when two different types of plastic can be used. This helps when there is difficulty in sourcing one type of plastic for mass production
- Good finish
- Has wide applications. Almost every manufactured thing around us, is manufactured through injection molding
- Injection molding allows greater detailing than any other molding process, because of the extremely high pressure the plastic is subjected to.
- It is a highly automated process performed by machines and robots. Just one person is sufficient to oversee the process. Hence this cuts down on manufacturing costs, as the overheads are reduced. This cost saving can be passed onto the customer. Much cheaper method of manufacture when compared to machining which can cost up to 25times more.
- Encourages research on more and more durable thermosetting polymers which can be used in injection molding.
Injection moulding in China is very well known the world over. They provide accurate moulding machines to specifications of mould makers in China and abroad. Mould tech in China is actually gone worldwide.