Force measurement using a piezoelectric crystal

Force is measured directly by means of a piezoelectric crystal and is not set using a force-current graph as in conventional DMA instruments. The force measured is that which is actually applied to the sample. Compensation for frictional losses, membrane force and inertia is no longer necessary.

More accurate displacement measurement

A special temperature-resistant LVDT allows measurements to
be performed over a large dis- placement range with nanometer resolution. The LVDT is located close to the sample so that only the deformation of the sample is measured. This eliminates any effect due to deformation of the stand and also improves the accuracy of measurement of the phase shift. The reproducibility
of the displacement measurement is improved by measuring the temperature of the LVDT sensor and correcting for the deviation.

Wide frequency range from 0.001 to 1000 Hz

The frequency range has been extended to the kHz region for the first time ever in a DMA instrument. In the shear mode, six decades are available. The region above 1 Hz is particularly interesting because it means that measuring times can be kept to a minimum.

Simplified sample holder system

The METTLER TOLEDO sample holder system is a completely new design that helps save valu- able instrument operating time. The samples are prepared and mounted externally in the sample holder. This can then be quickly installed in the instrument. The concept also allows you to change from one deformation mode to another without perform- ing an adjustment. For example, you can prepare a bending ex- periment while a measurement in the tension mode is in progress.

Touchscreen terminal – for dis- placement and force calibration

The touch-sensitive color terminal of the DMA/SDTA 1+ presents clear and precise information and is easily seen from a distance.

• All force and length calibra- tion routines are controlled via the terminal. This ensures that these operations are performed reliably and easily.
•  The 4-axis alignment adjust- ment is also carried out via the terminal; the resulting values are transferred to the STAR^e software. This eliminates any possible transfer errors.

Automatic switch mode

Force measurement also allows the instrument to be operated in a way not possible with conventional DMAs:
The instrument can be operated under either force or displacement control and an intelligent automatic switch mode is also possible.

Adjustment using reference standards

Sample temperature measure- ment and calibration/adjustment

Temperature calibration and ad- justment is particularly important. An additional temperature sensor is located close to the sample. The sensor also allows thermal effects to be simultaneously measured by SDTA (Single DTA).

DMA Experiment Wizard

The DMA Experiment Wizard, with its built-in expert knowledge, is designed to help users establish optimal sample dimensions, necessary for achieving accurate results. The software is also able to determine ideal force and displacement amplitudes.

www.mt.com/ta-dmawizard

3-point bending

This bending mode is ideal for measuring extremely stiff sam- ples, such as composite materials or thermosets, particularly below the glass transition temperature.

3-point bending

This bending mode is ideal for measuring extremely stiff sam- ples, such as composite materials or thermosets, particularly below the glass transition temperature.

3-point bending

This bending mode is ideal for measuring extremely stiff sam- ples, such as composite materials or thermosets, particularly below the glass transition temperature.

In the 3-point bending mode, the ends of the sample rest on two knife edges and an oscillatory force is applied to the middle of the sample by a moving knife edge

This bending mode is suitable for samples that expand or contract in the longitudinal direction during the measurement. This applies primarily to thermoplastic samples.

In the dual cantilever mode,
the ends of the sample are fixed and the middle is clamped to the moving part providing the oscillatory force.

Tension

Tension is the mode most suitable for films, fibers and thin bars and rods. The advantage is that sam- ple clamping hardly affects the deformation.

Compression

This type of measurement is less suitable for the determination of absolute values of the modulus; however, valuable relative infor- mation can be obtained when comparing soft materials like elastomers, pastes or foams.

Shear

The great advantage of the shear mode is that everything from vis- cous to very hard samples can be measured. This mode is therefore ideal for elastomers, thermoplas- tics, and thermosets.

In the tension mode, one end of the sample is fixed and the other is subjected to an oscilla- tory force. The sample must be prestressed to prevent it from buckling during the oscillatory movement.

In the compression mode, the sample is clamped between a fixed part and the moving part providing the oscillatory force. The sample is compressed statically and subjected to an alternating load.

In the shear mode, two identical samples are clamped sym- metrically between two fixed outer parts and a central moving part. The shear clamp guarantees a homogeneous temperature distribution.