Alignment Fixtures

Exact axial alignment of the test axis of the materials testing system is a basic requirement for determining accurate characteristic values.

Alignment must be performed very carefully, particularly when testing brittle materials such as fiber composites or certain metals.

Alignment fixture for alignment measurement

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Key Advantages and Features

  • Reliable test results through precise alignment of the test axes
  • Accurate positioning, reproducible and play-free adaption in each axis guarantees reliable test results
  • Angle and offset errors can be set independently from each other easily and quickly
  • Secure gripping of the alignment fixture for long-term retention of any adjustments
  • Adapting to top crossheads, moving crossheads, and base crossheads enables a flexible range of application
  • At a force level of 250 kN, there is an option that includes a flange interface, which allows for shorter test arrangements and a higher degree of stiffness

Exact Alignment Measurement

Function description

The alignment fixture is used to accurately compensate for angular and offset errors in the test arrangement.

The alignment fixture is an alignment element and is mounted directly on the testing system’s base crosshead. The adjustment screws are used first to adjust the angular error and then the axial offset. The screw configuration for making adjustments in the X and Y direction makes it possible to correct errors in their respective working direction. The alignment can take place in the loading state.

Alignment measurement

Precise guidelines regarding maximum permissible transverse loads are established in the respective application standards.

To verify machine accuracy, adjustment must take place in a loaded state using optionally available strain-gauged alignment specimens, measurement amplifiers, and ZwickRoell testXpert III testing software. The calculation routines comply with ASTM E1012.

Purely mechanical adjustment in an unloaded state can be performed via the mounting studs or via a divided specimen clamped in the specimen grips.

Mounting the Alignment Fixture

  • Alignment fixture in flange connection mounted between the load cell and the specimen grip (image on left)
  • Alignment fixture with bolt connection mounted directly on the crosshead (image on right)
Alignment fixture for alignment measurement
Alignment fixture for alignment measurement

Technical Overview

Alignment fixtures Fmax 50 kN and 250 kN

Item No.

058005

058006

068902

Test load Fmax

50

250

250

kN

In conjunction with

AllroundLine and symmetrical specimen grips

AllroundLine and symmetrical specimen grips

AllroundLine and symmetrical specimen grips

Load types (symmetric force application)

Tensile/compression/alternating load (static)

Tensile/compression/alternating load (static)

Tensile/compression/alternating load (static)

Permissible bending moment on the mounting stud/flange, max.

1

7.5

30

kNm

Offset correction (X/Y)

±3

±3

±3

mm

Attainable accuracy with offset correction

± 0.01

±0.01

±0.01

Angle correction

±1

±0.7

±0.35

°

Attainable accuracy with angle correction

± 0.006

±0.004

±0.002

°

Attachment

Stud Ø 36

Stud Ø 60

Flange connection

mm

Centering gauge

-

-

Ø 70

Pitch circle

-

-

Ø 220 mm (8 x M16)

mm

Connection

Centering gauge

Ø 70

Ø 70

Ø 70

mm

Pitch circle

Ø 115 mm (8 x M8)

Ø 220 mm (8 x M16)

Ø 220 mm (8 x M16)[1]

Dimensions

Overall height

152

211

145

mm

Installation space height

111

138

142

mm

Diameter

180

250

290

mm

Weight, approx.

14

34

49

kg

Ambient temperature

+10 ... +35

+10 ... +35

+10 ... +35

°C

  1. With intermediate flange (optional unit in Item No.)
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