Automatic linear density, crimp and tensile tester for single fibres

Test section FAVIMAT

The construction of the FAVIMATis basically a single fibre tensile tester with two additional measuring systems located in the tensile testing section. The highly sensitive load cell enables accurate adjustment of specified pre-tensions, as well as the measurement of extremely low tensile forces when determining fibre crimp properties. To ensure highest measuring accuracy, computer-aided calibration of all measuring systems can be carried out automatically.

The FAVIMAT testing methods

Linear density test

The measurement is based on the vibration method using the technology of the frequency interval method with acoustic excitation of fibre vibration and opto-electronic recording of the resonant frequency as applied to the VIBROMATME.

Static tensile test and examination of mechanical crimp properties

Tensile tests with the FAVIMAT deliver all relevant results such as (linear density related) breaking force and breaking elongation, modulus, intermediate values of the force/elongation-curve, work to rupture or characteristic values for elastic and plastic deformations.

Additional important data determined through tensile tests at very low tensile forces are the 'mechanical' crimp properties (percent crimp, crimp removal force) and crimp stability. 

Determination of crimp geometry

A further measuring system with opto-electronic sensor integrated in the FAVIMAT enables the creation of a digital image of the crimped fibre, which is held between the two clamps, and the subsequent evaluation of the crimp geometry regarding crimp number and crimp amplitude. As applicable to mechanical crimp properties, size, shape and regularity of the crimp geometry supply important information regarding the crimping process during fibre production, as well as the further processing of the fibres and the properties that can be expected from the intermediate- and finished products.

Test sequence

Depending on the task in hand, either one of the four tests or a combination of two, three or four tests can be carried out on a single clamped fibre.

The ROBOT² and AIROBOT² automatic fibre feed units

FAVIMAT ROBOT 2

For this purpose the automatic unit ROBOT² can be added to the FAVIMAT. ROBOT² comprises a sample storage unit and a transfer clamp, the latter for transferring the single fibre from the storage unit to the test section, and a suction system for removing the waste fibres after each test. The sample storage unit contains up to 20 magazines, each of which can accommodate 25 individual fibres. Therefore, the total capacity of the unit amounts to 500 fibres. Depending on the test requirements, the fibres are suspended in the magazines using tongs-shaped pre-tensioning weights, e.g. equating to the standard pre-loading for tensile tests, or paperweights for crimp tests. The magazines are transported in the sample storage unit via a paternoster-type system. During a running test series, empty storage magazines can be removed and reloaded.

The AIROBOT² is a variant of the ROBOT² automatic fibre feed unit. Here, the fibres are loaded pneumatically into the magazine in a semi-automatic loading unit. When being transferred from the sample storage unit into the FAVIMAT test section, the fibres are slightly pre-tensioned by a suction device. The AIROBOT² does not require pre-tensioning weights, resulting in an even more efficient test preparation.

Efficient testing with FAVIMAT ROBOT

Transfer clamp and magazine

When FAVIMATand ROBOT² are combined, the work of the operator is reduced to introducing the fibres into the storage magazine and, where applicable, attaching the pre-tensioning weights. After appropriate operator training, it can be assumed that the loading of 500 fibres into the storage magazines will require approx. 90 min. In case of the AIROBOT² this time is even further reduced to about 45 minutes. In the extreme case, this corresponds to a reduction in working time in excess of  95 %. When comparing the above figures, the enormous rationalization effect of the FAVIMATROBOT is clearly evident, which results from the combination of different test methods into a single instrument, together with automated sample feed and -disposal and the large capacity of the sample storage unit.

Testing methods

System components

Test section:

• 2 single fibre clamps, closure through spring pressure
• Continuously adjustable gauge length 5 – 100 mm
• Draw-off clamp speed 0.1 – 100 mm/min
  return speed 300 mm/min
  max. travel of draw-off clamp 100 mm
  
• Additional vertically movable measuring head that automatically swings into the test section, comprising two measuring systems for the measurement of linear density and the determinationof crimp geometry.

Measuring systems:

• Force measuring device, designed as a selfcompensating, path-free measuring system, resolution 0.0001 cN, measuring range 220 cN, other ranges available on request
• Elongation measuring device with resolver, resolution 0.1 μm
• Linear density measuring system with acoustic initiation of the fibre vibration and opto-electronic recording of the resonance frequency
• Opto-electronic measuring system for digital recording of the fibre geometry.

ROBOT:

• Fibre sample storage unit for a maximum of 18 magazines, each with a 25 single fibres capacity;
• Transfer clamp ROBOTto FAVIMAT
• Suction device to remove fibre residues from the clamps
• Loading unit for fibre introduction into the magazine with pre-tensioning weights (ROBOT) or pneumatics (AIROBOT)

Further technical data

Mains supply:

• 220 V, 50 (60) Hz, current requirement approx. 1.5 A.

Compressed air supply:

• 6 bar, 10 l/min

Lacquer finish:

• RAL7004/7035.

Dimensions:

• Height 610 mm, width 590 mm, depth 500 mm, weight approx. 102 kg (FAVIMAT)
• Height 1130 mm, width 660 mm, depth 700 mm, weight approx. 94 kg (ROBOT)

The above information can be subject to change by Textechno.