Dispensing and mixing applications

• Dispensing units: time- and pressure-controlled systems for liquids and pastes
• Dispensing valves: control of material flow for different viscosities
• preeflow® dispensers: volumetric dispensing for tight tolerances
• Robotics: benchtop robots and accessories for automated processes
• Consumables: dispensing tips, cartridges and accessories for daily operation
• Large cartridges: cartridge sizes and matching adapters for larger material quantities
• Accessories: Luer-Lock adapters, mixing nozzles, material containers and hoses

The technical difference lies in which physical variable determines the dispensing process.

In time- and pressure-controlled dispensing, the medium is conveyed by a defined supply pressure. The dispensing valve opens for a specified time. The dispensed quantity is therefore the result of the volumetric flow during this opening time.

The volumetric flow is influenced, among other things, by:

• supply pressure
• viscosity and temperature of the medium
• cross-section and length of hoses and dispensing tips
• flow resistance of the valve
• pressure losses throughout the material path
• fill level and pressure conditions in the material supply

In simplified terms, if the volumetric flow changes while the opening time remains the same, the dispensing quantity also changes. Time- and pressure-controlled dispensing therefore requires sufficiently stable process conditions.

In volumetric dispensing, the dispensing quantity is determined by the displaced delivery volume of the dispenser. The delivered quantity results from the geometry of the conveying element and its movement, speed or travel.

The supply pressure is primarily used to feed the medium reliably to the dispenser. Viscosity still affects the required pressure, torque, load and possible pressure losses, but it does not determine the dispensing quantity directly through the volumetric flow in the same way as in time- and pressure-controlled dispensing.

This makes it possible to decouple changes in material supply and process conditions more effectively from the actual dispensing quantity.

The following factors are particularly relevant when selecting the dispensing principle:

• target quantity per dispense
• permissible deviation of the dispensing quantity
• viscosity and rheological behaviour of the medium
• temperature range
• pressure conditions in the material system
• geometry and length of the material path
• cycle time and required volumetric flow
• process stability of the material supply

Time- and pressure-controlled dispensing is technically appropriate when the process conditions are sufficiently stable and the required dispensing tolerance allows it. Volumetric dispensing is used when the delivery volume must be defined directly and the influence of pressure and viscosity variations on the dispensing quantity should be reduced.

Not every dispensing or mixing task can be fully implemented with standard components. As soon as material supply, dispensing element, mixing technology, sensors, workpiece handling and control must interact, an application-specific system design is required. The complete process chain is considered, from material inlet to application on the component.

Project-specific system engineering

Development and construction of dispensing and mixing systems based on the specific process requirements. This can include material supply, pressure level, conveying principle, dispensing element, mixing section, hose and line cross-sections, dispensing tip, sensors, workpiece fixture and motion sequence. The aim is a technically coordinated overall solution for medium, dispensing quantity, tolerance, cycle time and degree of automation.

Contract manufacturing

Execution of defined dispensing, mixing or assembly processes as a manufacturing service. Existing processes can be carried out according to specified parameters, or new processes can first be tested under production conditions. This is particularly relevant when suitable dispensing technology is not available in-house or when a process needs to be validated before investment.

Product and process development

Technical design and optimisation of dispensing processes for new or existing products. This includes selecting the dispensing principle, defining conveying and material paths, coordinating dispensing quantity and cycle time, and assessing the influence of viscosity, temperature, pressure losses or the geometry of the dispensing point. Where required, the feasibility of automation is also assessed.

Commissioning and training

Integration of the system into the intended production process, parameterisation of dispensing and motion sequences and verification of the intended functions. Depending on the system, this includes setting pressure, dispensing time, flow rate, speeds, positions and process limits. Operators are then instructed in operation, parameterisation and basic fault analysis.

After-sales and technical support

Technical support after commissioning, for example when the medium, viscosity, dispensing quantity, cycle time or component geometry changes. Such changes can affect pressure conditions, conveying behaviour, dispensing parameters or the mechanical design. Existing systems can therefore be reassessed, adapted or extended where required.

Dispensing technology matched to the application

We develop and manufacture a substantial part of our product range ourselves. Complementary products are selected according to how they perform in practical use and how well they integrate into existing dispensing and mixing processes.

We do not recommend a solution if we do not know its technical limits.

If a time- and pressure-controlled dispensing system reliably achieves the required tolerance, there is no reason to make the process unnecessarily complex with a volumetric solution. Conversely, we do not recommend a standard product if the required dispensing quantity, cycle time or process stability cannot be achieved appropriately with it.

Requirements differ significantly depending on the application. A small batch at a manual workstation has different requirements for material supply, operation and dispensing principle than an automated series process with robots, sensors and defined cycle times.

We therefore start with the specific application and its technical boundary conditions. From this, it becomes clear which dispensing technology is appropriate, which components are required and what degree of automation suits the task.