Injection speed is an important factor of the injection technology in the production.Different product require different injection speed. different injection speed has different influence on the final product.

injection action

Characteristic and advantage of different injection speed

Advantage of using high injection speed:

  • reduce injection time,make cycle time shorter
  • increase the flow of the melt material, which is good for the forming of thin wall product
  • improve the surface gloss of the product
  • Can improve the strength of the weld line, so that the weld line is not obvious
  • Prevent cooling deformation, etc.

Advantage of using low injection speed

  •  Preventing the flash occur of the final product
  • Prevent the occur of spray mark and flow mark;
  •  Prevent the occur of burning marks;
  •  Preventing the air trapping situation of the melt material;
  • Prevent deformation of molecular orientation, etc.

The advantage of high-speed injection is also the shortcoming of low-speed injection, and vice versa. Therefore, the combination of high speed and low speed in the injection process can make full use of their respective advantages and avoid their respective shortcomings, thereby ensuring the quality of the product and the economics of the process.

This is what we usually refer to as multi-stage injection technology, which is commonly used in modern injection molding machines. At present, most of the medium-sized injection molding machines have five to six injection pressures, speed changes, and three to four-stage pressure holding pressure changes (during the pressure holding stage, the melt has filled the cavity, at this time the molten material is subjected to the pressure-holding pressure inflow type. The shrinkage of the cavity has been limited, so the effect of the pressure holding speed is not large).