It is well known that static mixers – so-called mixing nozzles help to avoid colour streaks in injection moulding. Less known is the fact that mixing nozzles can be used to solve many other quality problems, improve the process stability and reduce production costs.

Quality problems that can be solved with a mixing nozzle

Many quality problems in injection moulding have their source in the uneven temperature, viscosity and velocity of the melt. As a consequence, an improved homogenisation of these parameters help to improve mass tolerances and avoid undesirable effects like dull or brilliant surface areas.

Weak areas affecting the strength of the plastic part created by flow lines can be reduced significantly. It is already well known that mixing nozzles effectively avoid colour streaks due to improved mixing. A mixing nozzle is an efficient problem solver, and the injection moulding process can be improved in many ways that also bring significant cost savings.

Saving of masterbatch costs

More and more processors today are using direct colouring with masterbatch or liquid colours to reduce raw material costs and to increase production flexibility. However, it’s not always easy to get constant and even colour shades because the result will be affected by the process conditions of melt temperature, back-pressure, screw speed and the colour dispensing device. An accurate and constant gravimetric or volumetric colour dispensing system in combination with a mixing nozzle is the perfect solution for this challenge.

The mixing nozzle assures that a constant and even colour shade can be achieved independently from the injection moulding machine type and the processing parameters.

Also, the consumption of masterbatch and liquid colours can typically be reduced by 15 to 25% depending on the colour type and application. It is due to the efficient breaking down of colour pigment agglomerates and the homogenised distribution of the pigment particles.

Plastic & Chemical Trading together with international partner KraussMaffei Berstorff deliver world-class plastics, injection moulding, and extrusion solutions.