The five elements that injection moulding needs to meet is temperature, speed, pressure, position and time. These five factors determine the quality of injection moulded parts. And the above five factors are the key point of controlling qualified product quality.
Injection Moulding
The injection mould is a tool for producing plastic products. In the process of plastic injection mould processing, the plastic melted by heat is injected into the mould cavity by the injection moulding machine under high pressure, and after cooling and solidification, the injection moulded products are obtained. What are the features of plastic injection moulding processing?
Injection MouldInjection Moulded Parts
Injection mould is an indispensable tool in the plastic injection moulded parts production industry. Injection mould is generally composed of a total of seven systems: casting system, guiding system, forming system, core pulling system, ejector system, cooling system and exhaust system. The injection mould design is a very important step in the manufacturing of injection mould. In the design process, we need to take into account all aspects, so that finally the designed injection mould is able to meet the production needs. And then what are the points need to pay attention in the injection mould design process?
3D Design of Injection Mould
The components of plastic injection mould can be divided into two
categories according to their use. One type is the structuralMould Steel part, including the casting system, the guide part, the fixed (moving) formwork, the ejector component and the support part etc. The plastic injection mould materials are generally medium and low carbon carbon structural steels or alloys. The other type is moulded part, including cavity, core and inserts, etc., that are the key components of making plastic parts moulded directly. The working temperature of plastic injection mould is 200 to 300 °C. The cavity of plastic injection mould is complex, there are high requirements for dimensional accuracy and the surface roughness, and corresponding requirements are put forward for the machining performance of the plastic injection mould steel, the mirror polishing performance, the heat treatment deformation and the dimensional stability etc,. Therefore, When ACO Mould chooses plastic injection mould materials, while ensuring the performance requirements of plastic injection moulds, as much as possible to improve its processing performance.
With the development of science and technology, plastic injection moulds have become an essential tooling of producing plastic products in China plastic products manufacturing industry. In our real life, plastic products have almost captured all fields. Whether it is the parts of aircraft and cars or some of the commonly used toothbrushes and cups in our daily lives. In fact, those plastic products that are commonly used around us are not produced by the manufacturer one by one according to the drawings, but are produced in batches through plastic injection moulds.

Before plastic injection moulding manufacturer produce plastic products, the injection mould of this product will be made in advance. After the injection mould is completed, the manufacturer can mass-produce through this mould. Is the plastic injection mould manufacturing process complicated?

In fact, the plastic injection mould manufacturing process is very precise and complicated, because in the real life, plastic injection moulds are applied to various plastic injection moulding products, and many plastic moulded products must be manufactured accurately, such as plastic bottle mouths and caps. The production of them needs to be very delicate, because if there is a little inconsistency, it can't be combined. Therefore, when making plastic injection moulds, it is necessary to pay attention to such problems. The injection moulds must be made very precise which is possible to make high-quality plastic injection moulding products. Of course, for those plastic products that are relatively large and inexpensive, there is no high process requirement. For example, the mould of plastic basin doesn't require too strict requirements for the manufacturing process.
Plastic Injection Mould Factory

The following problems should be noted when choosing China plastic injection mould manufacturer:
  • Don’t just focus on injection moulding products design, ignore injection mould making.
  • Don't just pay attention to prices. Should have overall consideration from injection mould quality, production cycle, and injection moulding company service.
  • Avoid multi-head collaboration, try to make plastic injection mould making and plastic injection moulded parts processing integration.
The ejector system has a variety of forms. It relates to the shape, structure and plastic properties of the product. Generally, there are ejector pins, jacking tubes, push plates, ejector blocks, pneumatic composite ejectors, etc. The design principles of the ejector system are as follows:
  1. When selecting the parting surface, try to keep the product on the side of the mould release mechanism.
  2. Top output and position balance to ensure that the product is not deformed, not broken.
  3. The thimble should be located where it does not affect the appearance and function of the product.
  4. The use of standard parts as far as possible is safe and reliable for manufacturing and replacement.
  5. The ejection position should be set at a large resistance, not too close to the insert or core. For box type and other deep cavity moulds, the side resistance is the largest and the top surface and side surface should be ejected at the same time so as to avoid deformation of the product.
It is necessary to check and verify the easily damaged plastic injection parts and register them. Reserve the amount of inventory that may be consumed within 4 ~ 5 weeks, and record the damaged parts that have been replaced. Perform the inspection of common auxiliary equipment, and take a photo to record the position of the injection mould assembly.
The most common cause of black streak is the material residue in the injection moulding machine barrel.Residue remains in the plunger injection moulding machine.For valve gated injection moulding machine, the valve-regulated part also tends to remain residue.The air is compressed to a high temperature in the cylinder, with the high temperature gas in the gate, so it will be easy to be black streak.
Black Streaks
Residual gas inside the injection mould is compressed into high temperature state and burn the material.
Insufficient air discharging will cause burn mark.
Insufficient air discharging will also cause material shortage.
Burn Marks
In the nozzle and side slip, cooled resin flow into the mould cavity in a semi-cured state. After contact with the injection mould, the resin immediately cured, and then into a deep cavity formed flow mark.Different thickness of the plastic parts can also cause flow mark.
Flow Marks
Using only one sprue (gate), without confluence the material from two directions, in this way the molded parts generally do not have weld line. If you want to avoid weld lines, you can only change the position of the sprue in the injection mould so that the welding mark will not occur in obvious places.
Change the location of the sprue in injection mould
Same reason with reticular fracture.
If not well demolded, the release pin will apply excessive force resulting in molded plastics whitening.
Whitening refers to stress whitening. We can see from the stress yield curve and crack white perception that it indeed to the energy expended. Just add a little energy will crack after whitening. (Figure A)
ABS material yield curve
1 2 3 4 5

Online tour of our plastic injection mould making factory in Shenzhen China.
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