AB Lorentzen & Wettre ZD Paper Tensile Tester

L&W ZD Tensile Tester

Major benefits with automatic internal bond strength tester

Internal bond strength (paper’s strength in its thickness direction) is important for the production of multi-ply paper and boxboard. With L&W ZD Tensile Tester you can obtain fast and reliable internal bond strength values, which make it possible to achieve uniform strength across the entire web width, in compliance with customer specifications. L&W ZD Tensile Tester is easy to use, since the measurement sequence, including the application of tape, is fully automated.

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Full control of the internal bond strength, is particularly important in the production of multi-ply paper.

Low or unevenly distributed internal bond strength values, can cause problems in the layering of paper and boxboard in an offset press with sticky printing ink. If the values are too high it impedes the creasing of the boxboard, since the aim is that the material should delaminate in the score. High internal bond values also mean a waste of raw material and energy. In other words, the aim is to achieve an even strength

  • within customer specifications
  • across the entire web width.

Up to now, measuring internal bond strength has been a time-consuming and complex procedure. To meet production’s need for fast reporting of measured values, most rolls are only measured at 1 to 3 points, which makes it difficult to detect streaks with low/high internal bond strength.
Another problem with the Scott Bond method, for example, is that the handling of the instrument can affect both the level and the distribution of the measurement result.

Fast and accurate

L&W ZD Tensile Tester measures internal bond strength in paper and boxboard quickly, and with a high degree of accuracy.

The operator only needs to position the sample on the measurement table and press the start button. The rest is performed automatically by the instrument, including the application of tape to the sample. Measurement of a 1.5 metre strip in ten positions, takes only six minutes. The results are displayed immediately on the built-in and easy-to-read screen, and then stored in memory. The instrument displays a warning message if the results do not comply with the preset specifications. L&W ZD Tensile Tester can be connected to a PC for direct transfer of measurement data to production control.

Wide measurement range

Due to its interactive software, L&W ZD Tensile Tester is easy to configure. Up to 30 different test sequences can be pre-set and stored in memory.

The method suits most multi-ply paper types. Measurements are made in accordance with the SCAN P 80:98 and TAPPI T 541 standards.

The Z-directional tensile and Scott Bond method are different methods to measure the material’s strength in the thickness direction. The ZD- tensile measures the maximum force to split the sample at a low standardized test speed perpendicular to the test surface. The Scott Bond method measures the energy needed to split the sample at a speed several thousand times higher. The methods do not always react the same for changes in the papermaking process.

Specifications
  • Measures internal bond strength quickly and correctly
  • Perfect for troubleshooting
  • Automated testing, including the application of tape
  • Operator-independent measurement results
  • Unique compression device for perfect alignment of upper and lower test surface
  • Traceable calibration
  • Measures with high pulling speed according to the ISO draft, for even more reliable results
  • L&W ZD Tensile Tester received the “Excellent Swedish Design” award in 1998
Specification

L&W ZD Tensile Tester – Code 155
Inclusive
 Pulling unit 10 cm² or 1 in². 4 rolls of tape.


Measurement

Range

For paper and board and not corrugated board.  The adhesive capacity of the tape to the test piece and the tester platen is the one and only limiting factor for the upper limit of the measuring range. When measuring thin paper samples, with a grammage lower than 60 g/m², there is a risk that the tape will reinforce the test piece, which will give an incorrect measuring result



Instrument

Testing modes

- individual measurement
- measurement of a sample strip
- measurement of several sample strips in sequence

Test piece
 width approx. 100 mm, max. length 1500 mm per test sequence
Test frequency
 1–20 per test piece
Distance between measurement points
70–200 mm
Measurment area
10 cm² or 1 in²
Tape
Double-sided self-adhesive
Tape width
50 or 75 mm
Compression time
6– to 300 seconds
Compression force
Adjustable


Results


 Measurement values
- ZDtensile strength
Statistics
- mean value
- standard deviation
- coefficient of variation



Connections

Data

RS232C
- connectable to L&W Autoline Data Acquisition Workstation

Printer
Parallel


Installation requirements

Power
100 W
Instrument air
0.6 MPa–1 MPa (90–145 psi)

Size

Dimensions

0.9 × 0.4 × 0.7 m
35 × 19 × 27 in

Volume

0.6 m³
23 ft³





Net weight

78 kg
172 lb

Gross weight

108 kg
238 lb

Standards

Applicable standards
SCAN P 80, TAPPI T 541, new suggestion for ISO standard

 

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