Plastic Injection Moulding Technology

- Sep 06, 2017-

Injection Moulding is the most important in today’s industry and on consume market. Especially for the automotive and social live, such as auto parts, home appliance, commodity, etc.

Plastic Injection moulding is a manufacturing process for producing parts by injecting different kinds of plastic into a mould, and after cooling, products is done..

Injection moulding is one of the chief processes for producing plastic items. It is a fast process that can deliver a large numbers of identical items - from high precision engineering components to small disposable consumer goods.

While,do you know, different kind of plastic material request different kinds of mould steel? Just as there are many kinds of plastic material, and there are also a lot kinds of mould steel. Most common mould steel is P20 and 718,H13.This is just used for common mould. But as for the special mould, need choose mould steel accordingly. For example, if we need make a refrigerator mould, better to use 8407, nak80, or S136, because these material are very good to make good surface. But if you need make an auto fan mould, which material is PA66+30%GF, then it is better to use H13, or 2344, because these material after heat treatment, the hardness can be over 50hrc, very good for auto fan mould.

The mold technology is developing to improve the process of the injection mould.

The following are some of the key improvements in injection moulding:

  • Sandwich moulding



a.     First surface skin polymer injection material 1.

b.     Second inside core polymer injection material 2

c.     Almost full fill the cavity material 2,

d.     Then inject the surface skin polymer to cover with material 1,

  • Gas assistant moulding

Gas injection technique is to use nitrogen injected into the part to replace the melt in the core and create a hollow space,this can reduce the weight of the parts by 50%, and make good surface of the parts, can save a lot.

  • Water assistant moulding,

Water assistant moulding is to use water to replace nitrogen to assistant the injection process, this is new method, and it has better advantages, because  provides lesser cycle times, smaller and constant wall thickness with less warpage, large part diameters, and smoother inner surfaces. Additionally, water is cheaper than gas and is incompressible.

  • Dual-Shot Injection Moulding

 ‘Two-Shot’ injection moulding or dual-shot injection moulding is a method to produce simple to complex parts comprising two different polymers even with two different colours during one machine cycle.

The ‘Two-Shot’ mould consists of two separate cavities that are used for making a single part. Here are a few variations of two-shot molding, including rotary platen, movable core, and overmold. The first two require a second injection unit, two runner systems, and two processes. The latter, in most cases, involves two separate molds—one for each material—but can also be run with one mold, two runner systems, and pick-and-place part transfer, either manually or with a robot.

The key benefits of the ‘Two-Shot’ injection moulding are as follows:

  • Soft touch features and      multi-color on handles, grips, devices, enclosures, and other components

  • Back-lit buttons, dials      and other instrumentation products

  • Noise/vibration dampening      and isolation

  • Air/water seal

  • Shock absorption and      protection

  • Movable segments or      components such as living hinges and spring type mechanisms

Stack Molds

Stack moulding are a series of molding faces “stacked” together to create multiple faces or levels for molding.

  • Each level or face is a      parting line and produces molded product.

  • The benefit of stack      molding is to increase the output of a given molding machine and      operation.

  • Special machine      considerations are required to run stack molds, however StackTeck’s      technical team are well versed in providing guidelines and recommendations      to ensure success when adopting a stack mold strategy.

  • StackTeck provides stack      molds in 2, 3 and 4 level configurations based on part designs and volume      requirements. Molds can also be converted from 2 to 3 to 4 levels as      volumes increase.

  • In many cases, parts with      a large projected area can be converted or built in a stack mold      configuration, doubling the output of a given machine.