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Dosing and Mixing

The production of the reactive mix is a decisive step in the process chain in many respects:

Exact adherence to the mixing ratio and the mixture quality have an important effect on the product quality. In case of sensitive products, even the smallest deviations in the mixing ratio as well as the smallest defects in the homogeneity of the mixture can lead to reject production.

The mixture is reactive, that means

… it must be used productively, otherwise the material brought in is wasted.

… the viscosity increases exponentially, any delay in further processing leads to deterioration of the mechanical and electrical properties of the produced components.

Instead of producing the reactive mix in batches, HÜBERS systems therefore rely on controlled mixing of the material components in the smallest required quantity immediately before processing the mix. We achieve this through the interaction of our pump and drive technology with our static mixer.

In addition to exact adherence and reliable reproducibility of mixing parameters, HÜBERS technology for dosing and mixing offers significant advantages for production management and productivity:

  • continuous operation possible, no interruptions due to preparation of new material batches
  • immediate start of production at the start of a shift; production can be resumed easily after interruptions
  • shorter cycle times possible due to higher processing temperature of the casting material
  • no sedimentation problems

Component Flushing Valve

Directly in front of the static mixer is the patented HÜBERS component flushing valve, which closes the hardener side to flush the mixer with the resin component. During flushing, the valve prevents hardener from entering the mixing channels.

The flushing valve is also used for material systems with components other than resin and hardener, e.g. liquid silicones. The properties of the system determine which component is used for flushing.

The static mixer is cleaned quickly and reliably solvent-free with the smalles possible amount of material. In this way, no plugs or deposits can form.

Development of the viscosity of the reactive mixture when mixed in a batch mixer
Development of the viscosity of the reactive mixture when mixed in a batch mixer
Development of the viscosity of the reactive mix when using the HÜBERS technology
Development of the viscosity of the reactive mix when using the HÜBERS technology

Dosing Pumps

The dosing of the material components is volumetric and is controlled by servo motors with high-performance resolvers.

The dosing pumps transport the components into the static mixer. Here, precise dosing, high wear resistance and tightness of the pumps are of particular importance. Our patented HÜBERS piston dosing pumps operate independently of gravity and are absolutely pressure loss-free.

Depending on the application, vacuum-tight gear pumps or combinations of piston and gear pumps are also used.

Fully ceramic piston dosing pumps are used optionally. This version is even more resistant to the physical stress caused by casting media and is therefore particularly recommended for processing highly abrasive materials.

Drives and Control

For the accurate dosing of the components for the production of the reactive mix, the dosing pumps require a drive system that ensures exact synchronicity of the pumps and exact adherence to flow rate and mixing ratio. Electronically controlled individual drives offer a maximum of control and monitoring options for all casting parameters.

  • brushless servo motors with high-performance resolvers
  • drive shaft from above through vessel lid and stirrer axle of the dosing mixer, 6-fold vacuum sealing of the drive channel
  • connection of the pumps in master-slave configuration
  • permanent monitoring of the synchronicity by electronic surveillance of the pump pistons’ traveling distances
  • control, monitoring and programming via graphical user interface on a touch screen

Static Mixer

In the static mixer the individual components are mixed to create the reactive mass. It consists of individual stainless steel segments, which are precisely aligned in a guide tube and sealed vacuum-tight. In each segment, the number of component striations is quadrupled; the mixture of the two components thus consists of 130 million striations after 13 segments, for example. This ensures the homogeneity of the reactive mixture.