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Potential savings

Part costs

up to


Clamping force

up to


Part weight

up to


Production area

up to


Cycle time

up to


Energy requirement

up to



Injection-compression molding (ICM) in a stack mold is an absolute novelty in the industrial production of packaging.

The injection-compression process is different from conventional injection molding due to the method of the resulting material shrinkage in the cavity ("shrinking effect") being compensated during the cooling of the melt. In conventional injection molding, this is carried out during the hold pressure phase via a "pressing" of additional material. Conversely, during the ICM procedure, the "shrinking effect" is compensated for by an actual compression process. As a result, material savings of up to 25% can be achieved.

Due to the incredibly fast injection times, the filling of the cavities is lightning quick, yet extremely even. Due to the reduced pressure, stresses in the product are avoided.

In summary, the ICM procedure provides unbeatable savings in cycle times as well as material and energy consumption, and increases the quality of produced packaging at the same time. Using a stack mold significantly increases the level of productivity.


Technical advantages

Economical advantages

  • Reduction of inner tensions
  • Reduction of distortion
  • Improvement to the molding of diverse structures
  • Improvement of dimensional accuracy
  • Reduction of sunk spots
  • Improvement of filling behavior for high flow path/wall thickness ratio (L/T)
  • Optimal flexibility of product design and decoration in combination with IML
  • Reduction in the required clamping force

Product/ICM production­system


15 oz / 425g Tub

Image   Weight per tub:


Image   Dimensions per tub:

   137 x 92 x 63 mm

Elion 2800 - 2000 ICM

Cycle time 5.0s | Mold 4+4 cavity Stack Mold

Robot: Take Out / IML

Requirements for ICM

The successful implementation of ICM requires the demands on the machine design and control to be extremely high. For this reason, Netstal injection molding machines are optimally suited for the application of the injection compression process:

  • Metering accuracy
    • Because corrections of the filling via hold pressure are not possible, extremely high demands on the metering accuracy result.
  • Dynamics
    • The fundamental requirement for the perfect distribution of the melt in the ICM procedure is an extremely dynamic and precise working clamping unit.
  • Injection performance
    • To make «compression» of the material possible, an ultra-fast injection performance (>800mm/s) is necessary.
  • Synchronicity
    • For the achievement of the most precise reproducibility, a highly precise and synchronous interaction of the injection unit and clamping unit is imperative.
  • Parallelism
    • The injection when the clamping unit is in the open state places particularly high demands on the plate parallelism and design of the toggle lever.



Cavity internal pressure

standard injection molding


Varying pressure distribution in the cavity → distortion


History & experience

Optical Discs CD & DVD
Netstal Disc 60
1985 Netstal Disc 60

Netstal Discjet 60
Netstal Discjet 60

Netstal e-jet 60
Netstal e-jet 60

425g Tub Stack Mold
Netstal Elion 2800 ICM
Netstal Elion 2800 ICM