Baby Diapers                Adult Incontinence               Sanitary Napkins

Disposables Manufacturing

Hardy Integrity Tester

If you are, or want to be,  involved in any facet of the manufacture or sale of baby diapers, sanitary napkins, adult incontinence or similar absorbent products, please read through our pages and contact our Consultant, Philip Hardy, by phone,  fax or  e-mail. 


An electro-mechanical device for the repetitive raising and dropping of disposable absorbent products in front of a light box in order to quantify the breaking strength of the absorbent core within the outer envelope and to observe the mode and position of breakage.

The product can be tested in a dry condition or with a specific targeted insult so that the dry and wet strengths of the product can be determined at different stages of saturation.

A reliable and consistent test device for the determination of a pad strength parameter in absorbent products such as diapers, underpads, shaped pads or sanitary napkins.

The device can be fitted with a fixed or variable speed motor. Our standard operating speed is 60 drops per minute. The electrical cabinet has a counter, a motor speed console, a setting indicator and an emergency stop button.

A remote Stop/Start hand operated console is provided so that the device Operator can stop and start the unit while still observing the test piece at the front of the unit.

Hardy Integrity Test Brochure

Pad Integrity Test


The ability of the absorbent core of a disposable product to remain intact before and after absorption of fluids despite the dynamic impact from the wearer is an important performance parameter of the product.

Our HIT device is the only tester available on the market that reliably and consistently evaluates the strength of the absorbent core within the product envelope. This new device and test method finally provides a reliable means of evaluating the core integrity.

This video shows the electronic version. A video of the manual version is shown below.

  The strength of the absorbent core is dependent on several factors -

Fibre length
Fibre entanglement
Pad density 
Pad embossing pattern
Core structure

Adhesion to roll materials
Superabsorbent distribution
Core shape
Drum forming consistency

The Hardy Integrity Test (HIT) method and device finally resolves this issue for disposables manufacturers. A real evaluation of the integrity of the core can be achieved for production consistency monitoring and as a key design development parameter.

Test Categories

Consistency testing
Drum forming

SAP and fluff homogeneity

Glue application
Core compression / embossing
Bifolding damage
Package compaction

Development testing
Removal or reduction of tissue layer

Improvement of adhesive bond

Modification of embossing or compression
Modification of absorbent core structure
Adjustments in fluff and SAP content

Comparison testing
Comparison with other brands in dry and wet states
Comparison with other pad structures


Device Function

All longitudinal elastics are cut from the absorbent product (if present).
The trial products are placed in the clamps thus suspending them in front of the light box
The height of drop is set at the required level (0 to 80mm).

The light box is switched on.

The motor is switched on and the product is repetitively dropped from the set height until a complete crack is observed across the core.


Typical Test Results



The above test results were achieved for two very different baby diaper cores. The blue curve was a diaper without a carrier material, the red curve was a diaper with top and bottom tissue glued to the core.
The Diaper break-up curve is created from the average values for a set of samples. A characteristic curve is produced for a specific insult quantity.

The scatter chart above shows the HIT results for the diaper Sample B. Each point on the graph is a test result for a sample diaper. The X axis is the drop height and the y axis is the number of times the diaper was dropped before a full failure crack appeared in the core. This general funnel shape is typical of all HIT results; the test results being more closely grouped as the drop height increases. The narrower the funnel shape,the more consistent is the drum forming operation.

The daily or weekly drop height graph will give indications of two quality parameters:

  • Consistency of the pad formation. Any cassette (mould) defects can be quickly identified. Improved consistency of pad formation will be reflected by a narrowing of the range of results.
  • Improvement in the pad integrity: A rise in the average line (red line above) indicates general improvement of the pad integrity of the product.

Contact us at Disposables Consultancy Service if you would like to receive more information. A video of the test and device is available on request. Please contact us if you require a price for this equipment.

Equipment Options:
The standard light box is 900mm high x 600mm wide and will be adequate for testing all products up to 1300mm high. Smaller vertical light boxes, 600mm high x 450mm wide are available on request.

The lightbox frames are generally off-white (RAL8016), but can also be in black. (See device at top of page)
Electrical power can be 120 or 220V.

Manual Hardy Integrity Tester


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Disposables Consultancy Service
Copyright 1999  [DCS]. All rights reserved.
Revised: October 2013

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