Colour Changing Systems

Depending on product and requirement, one can choose from about two dozen different systems. The right selection will mainly be subject to what has to be changed - basic colour, stripe colour, both colours, the wall thickness and material of the insulation as well as the frequency of the colour changes. Accordingly combinations of two and up to five extruders are used together with one or both of the following changing valve systems. UNITEK offers the patented UCCS valve as well as the ULCS valve which is working according to the layer change principle.

colourchangingsystems
Product Folder:
Download pdf

Changing valve system UCCS:

  • Change over between the two extruders is made by turning the piston
  • One extruder is in working position the other one is in bleeding position (stand-by)
  • In the extruder currently in bleeding position the colour is changed to the next one to be produced
  • The piston has 1 working and 2 bleeding channels. The material flows left/right (red) or right/left (yellow) into the head and never stands still inside the working channels
  • During change over the material flow is not interrupted (see middle position)
  • An axial movement of the piston brings both extruders in bleeding (bypass) position
  • Particularly suitable for thin wall products and short production runs

 

Changing valve system ULCS:

  • Depending on the position of the valve, the mass from one extruder is diverted to the inside (non visible) whereas the other is diverted to the outside (desired colour)
  • During switch over the material flow is not interrupted (see middle illustration)
  • Colour changes are made in the (non visible) layer
  • No extreme short production runs (time required for colour changing in the inner layer determines minimum length)