Technology requirements

From tooling point of view: Special designed tool insert with 3Dcavity surface followed cooling channels for the higher effectivity on the tempering of the melted plastic in the cavity.
Special equipment for the tool cavities heating and cooling

 

Advantages

  • Using for low wall thickness (e.g. wall thickness reduction -> piece price reduction)
  • Normal or higher wall thickness with faster cooling -> cycle time reduction
  • Different wall thickness on the same part, uneven wall thickness areas without sink marks, and reduced internal residual stress ! -> more “freedom” for the part design, and the reduced residual stress means lower deformation after the molding process (post shrinkage and deformation)
  • Sinkmark-less and flowline less technology for the aesthetical parts.
  • More uniform distribution at the glass fiber filled parts ->better aesthetical appearance and better mechanical condition

 

Disadvantages

  • Higher tool price
  • Higher energy consumption as at the conventional moulding
  • The disadvantages sometimes more than 100% compensated with the lower cycle time – depend on the yearly production quantity and the part design.
  • Sometimes no another feasible technology solution -> part design, aesthetical requirements

Conventional cooling system of the injection moulding tool

Conventional moulding

 

Variotherm cooling system of the injection moulding tool

Variotherm cooling

2 different cooling water temperature level during the moulding cycle:

  • First period of cycle – under the moulding of the plastic into the cavity,  the temperature is high (130-150 C° degrees)
  • Second half of the injection process very fast cooling down (16-20 C° degrees)  of the cavity -> plastic material in the cavity
  • Better surface quality, lower residual stress, because the high temp. cavity could fill the plastic material with lower injection pressure