TriPAV

Compact. Powerful. Unrivalled.

Specifications

Rheometer

Solid state high frequency rheometer requiring little or no annual maintenance/calibrations

Frequency range:

1 Hz to 10,000 Hz 

Temperature range:

5°C to 80°C

Viscosity range: 

1 mPa.s onwards

Sample required:

< 0.1 ml

Sample thickness: 10 µm to 1 mm -depending on sample viscosity and frequency range required.

Size:

Main Unit including heating/cooling jacket:  8 cm x 9cm x 10 cm

TriPAV High Frequency Rheology

1Hz to 10,000 Hz sweep,   < 5 minutes

TriPAV complete set-up with Lock-in amplifier, thermostat circulator, digital thermometer and TriPAV operating software.

TriPAV Printhead Mode

20-50°C temperature sweep at 1°C interval,  < 30 minutes

TriPAV Printhead Mode  complete set-up with oscilloscope, thermostat circulator, digital thermometer and TriOsc operating software.

Applications

High frequency dynamic sweep from 1 Hz to 10,000 Hz of

  • Inkjet Inks: Viscoelastic properties of inkjet fluids at conditions similar to those experienced in the printhead channel during jetting.
  • Low viscosity continuous inkjet inks
  • High viscoelastic enamels, paints, coating inks and polymer solutions.
  • Volatile solvents and inks
  • Micro-rheology characterisation (< 0.1 ml sample): Highly suitable for high value and low volume samples such as bio-fluids, blood, protein and functional fluids.
Examples

Background

Conventional oscillatory rheometers normally are unable to oscillate above a frequency of 100Hz.

  • Although, this is adequate for many polymer systems and structured fluids, the maximum frequency of the conventional rotational rheometers is too low to detect any viscoelastic effects for the very low viscosity of ink jet fluids.
  • At high frequencies, the inkjet fluid exhibits a low level of non-Newtonian behaviour, which strongly influences the fluid jet-ability.
  • The high frequency rheology give insight into subtle changes in the ink dynamic properties between batches, colours and formulations.
  • The high frequency visco-elastic analysis has been extensively used by:
    • Ink formulators to shortlist additives and resins and develop reliable inkjet inks for specific printheads.
    • Printhead manufacturer, system integrators to optimise waveform features and predict jet-ability of inks.
    • Chemical manufacturers to develop inkjet suitable additives and resins.
    • Coating formulators to convert analogue paints/enamels to inkjet inks.
    • Pharmaceutical and biomedical studies.

Descriptions

The Trijet TriPAV is a hermetically sealed high frequency rheometer capable of measuring the linear viscoelasticity (LVE) of inkjet inks, paints, enamels, volatile solvents, functional fluids, polymer solutions, and soft matter fluids such as blood, bio-fluids and protein solutions. 

TriPAV is the only rheometer that can measure the complex viscosity of inkjet inks at conditions that mimic those experienced in printhead channel

It has a frequency range from 1 to 10,000 Hz and can carry out the entire frequency sweep in less than 5 minutes.  It requires less than 0.1 ml sample to carry out the test.

The high frequency rheology data has been proven crucial for inkjet studies to correlate fluid dynamic properties to jetting behaviour.  TriPAV provide useful tool in

  • Ink formulation: aid formulation of good inks by being able to identify and tailor subtle changes in the complex rheology from ink components.
  • Quality control: by being able to differentiate between apparently identical inks but that show different jetting behaviour,  and
  • Jetting optimisation: Ability to recommend optimum jetting temperature and print frequency.

Principles

Solid-state rheometer with active and passive piezoelectric elements.

  • Squeeze-flow rheometer whereby a small quantity of fluid is held between two flat plates and one of plate is oscillated by a piezo actuator using Lockin amplifier.
  • Piezoelectric excitation (<< 10 nm similar to that encountered in printhead channel during jetting; 0.01-0.2% strain) of the lower plate by means of external Lockin amplifier and the overall response is captured by the passive piezoelectric sensor.

Analysing the change in the response amplitude and phase of with and without the sample, complex linear viscoelastic properties: elastic modulus (G’), viscous modulus (G”) and complex viscosity (h*) is determined over the range for frequencies 1 – 10,000 Hz.