Plastic Injection Molding, simply stated, is a manufacturing method to mass produce plastic parts. With the advancement of technology, the demand for plastic products has steadily increased. This has led to the growth and development of the plastic injection molding industry. Plastic products are today ubiquitously seen in many industries which include medical, aerospace, plumbing, and construction as well as for smaller component that go into the assembly line of huge panels.
An Injection molding machine, sometimes called as an injection press, is a machine for manufacturing plastic products through the injection molding process. Injection molding allows manufacturers to produce quality plastic components repeatedly in a cost-efficient manner. Injection molding is a process analogous in many ways to die casting for metal components.
The injection system consists of a hopper, a reciprocating screw and barrel assembly and an injection nozzle. Injection molding machines firmly hold the molds in either a horizontal or vertical position.
There are different ways to fasten the tools to the platens - the most common method is using manual clamps whereby the two halves are bolted to the platens. However hydraulic clamps, where chocks are used to hold the tool in place, are also widely used. There are also the magnetic clamps used where fast tool changes are required.
The horizontally oriented machines are the ones predominantly used but vertical machines are used in a limited way in some niche applications such as insert molding, allowing the machine to take advantage of gravity.
Plastic industry has brought an evolution as never before and today plastic machining is in huge demand. Plastic Machining and particularly CNC Plastic Machining are known for their durability, precision work and reliability. Fabricating plastic parts are usually done by CNC Plastic Machining, where every operation is controlled by technology, through computer software controls.
As CNC Plastic Machining is precise and error free, it is useful in many applications within medical, automotive, fluid handling and other sectors where measurements need to be exact. Being an effective alternative to metal machining, it allows for light weight, flexible, and corrosion resistant parts and components.
Injection molding machines are classified by the type of driving systems they use hydraulic, mechanical, electric, or hybrid. For long, hydraulic presses had been the only option that was available to molders. It was during 1983 that Nissei Plastic Industries introduced the first all-electric injection molding machine.
The electric press reduced the operation costs by cutting energy consumption and also removed some of the environmental concerns pertaining to the hydraulic press. Electric presses were found to be faster, more efficient and had a higher accuracy. But the electric presses were far too costly.
Mechanical type machines use the toggle system for building up tonnage on the clamp side of the machine. This means tonnage is a must on all machines so that the clamp side of the machine does not suddenly open unable to withstand the injection pressure. If the tool half opens up it will create flash in the plastic product.
Hybrid injection molding machines reportedly incorporates the best features of both hydraulic and electric systems, but in actuality use almost the same amount of electricity to operate as a standard hydraulic. Hydraulic machines, though not known for precision, are the predominant type used in most parts of the world.