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Precise injection moulding cooling with optimum die temperature control

Reduce your injection moulding cycle times and produce plastic parts with flawless surfaces

From armatures to car bumpers, and from mobile phone outer shells to model cars: Quality and price are key criteria when injection moulding plastic parts. How do you injection mould high-quality products despite increasing cost pressure? By drastically reducing your cycle times:

Fabrik-Icon und verschiedene Spritzgussteile

 

Would you also like to cool your injection moulding dies quickly and with a high degree of repeatability? Find out here how easily it can be done.

Injection moulding at a glance

The injection moulding process sees the mass production of complex moulded parts. In this case, the granulate is plasticised and pressed under high pressure into the injection moulding die. The complete cycle time is around 10 to 30 seconds.

Cooling
Temperature control

In conventional cooling processes, the die temperature remains constant throughout the entire operation. This has certain disadvantages for you:

  • Matt surfaces
  • Visible flow lines
  • Flow lines and weld seams
  • Quality defects
  • Ribbed structures
  • Reworking to achieve desired surface structures

However, you do not have to accept these disadvantages. Learn more about flexible temperature control from Bürkert:

The solution: Variothermal cooling of injection moulding dies

Unlike conventional temperature control, the Bürkert solutions deliberately adjust the temperature of the circulating medium during the injection moulding cycle. In addition, the ability to control temperature close to the contours cools your dies quicker and shortens the cycle time considerably. Further advantages:

  • Optimally temperature-controlled dies
  • Plastic parts with flawless surfaces that are completely devoid of deformations or flow patterns
Through variothermal temperature control the die wall is temporarily heated to a temperature between the glass-transition temperature and the melting point of plastic. This delays or prevents the solidification of the molten material, maintains its low viscosity until the mould is fully filled and lowers the required injection pressure / closing force.
During cooling, the holding pressure also acts for longer in areas further from the injection points thanks to the uniform filling of the mould. This ensures a uniform cooling time throughout the die.
Start/Stop signal from the injection moulding machine
Actuator valves

The advantages of variothermal temperature control:

  • High-gloss surfaces free of flow lines and weld seams
  • Surface textures and microstructures can be achieved
  • Improved mechanical properties
  • Reduced injection pressures for extremely small cross sections
  • Sink marks with extreme wall thicknesses are prevented
  • Reduced cycle time for thick-walled parts
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High quantities, best quality

For injection moulding plants, exact and repeatable temperature control plays a critical role. This guarantees plastic parts in large quantities – free of distortion, to precise dimensions and with the required surface quality:

  • Quick changeover between hot and cold temperatures
  • Short cycle times

Injection moulding: Reducing the cooling time

Cooling injection moulding dies costs time and consequently money – it takes up two thirds of the cycle time. Reduce your cycle times with close-to-contour and modular temperature control from Bürkert.

Opening the die
Demoulding
Closing the die
Filling time
Holding pressure time
Cooling time

Variothermal process temperature control

Depending on the required flow rate of the temperature control medium, the appropriate nominal orifice is selected. We configure your variothermal temperature control solution individually for you.

Modular system for nominal orifices from DN15 to DN25

Using the basic housing and standard welding process, we manufacture a temperature control unit tailored to your plant for nominal orifices from DN15 to DN25. According to the application, you choose the required pressures, temperatures and flow rates:

 

INOX system for nominal orifices starting from DN10

The process valve block INOX is designed for variothermal temperature control of nominal orifices starting from DN10. The modular design allows the configuration of almost any desired solution.

Fotografie des Inox-Grundmoduls

The INOX base module offers:

  • Multiple connection options
  • A compact pneumatic actuator measuring 30 mm in diameter
  • Stainless steel DN10 nominal orifice

Place the valve block as close to the die as possible, thus reducing the volume of liquid between the switching block and the die. The advantage: When switching from cold to hot or vice versa, the change in temperature affects the die immediately.

This is how INOX from Bürkert works:

A valve station positioned between the die and the temperature-control device performs the switching from heating to cooling or vice versa.

Heating phase: Valve V1, V3, V5 opened, V2, V4, V6 closed. Up to 200° C medium flows through the die. The cooling circuit is short-circuited by a bypass valve (V5).

Cooling phase: Valve V1, V3, V5 closed, V2, V4, V6 opened. Only cold medium flows through the die. The heating circuit is short-circuited by a bypass valve (V2). The bypass ensures continuous operation.

Grafische Darstellung der Heiz- und Kühlkreisläufe innerhalb des Inox-Moduls

A1 die supply line   P1 die return line
P2 cooling supply line (from temperature control device)   A2 cooling return line (to temperature control device)
P3 heating supply line (from temperature control device)   A3 heating return line (to temperature control device)

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Whether modular system or INOX process valve block:

✓ In both cases, you profit from the same functionality
✓ You receive a ready-to-install, plug-and-play temperature control unit

Six reasons why variothermal die temperature control is by far the best option

Plug-and-play temperature control unit from Bürkert

Why develop a system from individual components if you can integrate a ready-to-install assembly? You do not need to order, store and assemble any individual parts. Instead you receive compact, easy-to-handle systems. You also avoid the need to test the tightness, electrical function and pressure resistance.

Fotografie der Modularen Temperiereinheit

 

Injection moulding cooling: This is how you save time and development costs

Developing a suitable temperature control takes time. The example calculation shows: A fully preconfigured unit will save you numerous development steps. We carefully match components together with you. This drastically minimises the amount of work involved.

1 Engineering the temperature-control solution
2 Coordination with other departments/suppliers   
3 Adjustments
4 Ordering the individual products
5 Goods receipt inspection of the ordered products
6 Design + assembly + testing
7 Adjustments, if necessary
8 Total time required for engineering and designing a temperature-control solution
9 Customised temperature-control units

 

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Would you also like to save engineering time when developing cooling solutions?
We will be delighted to advise you and make recommendations for your individual temperature control challenges.