Automatic Shore, IRHD and VLRH Hardness Testing System

Hysteresis describes a material whose response depends on its history, not only on the load acting at that moment. Loaded and then unloaded, rubber does not travel back along the same path.

In hardness testing this makes the reading depend on timing. The value is tied to the interval between the change in load and the moment the depth is read, so the dwell must be fixed and repeated exactly. On the Digi Test II the measuring time is programmable from 1 to 99 seconds.

A dedicated hysteresis function is available with the IRHD L unit for specimens 10 to 12 mm thick, and with the Shore 00/000 and VLRH units used on foam rubber, sponge and silicone. Our article on the value of hysteresis in rubber and plastic hardness testing covers the background.

The difference lies in how the load is applied while the loop is recorded. In a static measurement the load is raised and lowered in steps, with the deformation read at each step. In a dynamic measurement the specimen oscillates continuously, and the energy loss is followed against frequency and strain.

The Digi Test II works on the static side. Its hysteresis function automatically runs several cycles of gradually increasing and decreasing load on the indenter, so both branches are taken under the same conditions every time.

For dynamic work on compounds we offer the RPA Ultra rubber process analyzer. It oscillates the sample from 0.001 to 100 Hz, includes a hysteresis subroutine and calculates G′, G″ and tan δ for raw compounds and elastomers through the cure.

The RPA Ultra describes the compound; the hardness-based check is made on the test plate or finished part.

Hysteresis is a useful indicator of durability, but one input among several rather than a verdict on its own. It shows how much energy is lost as heat in each loading cycle, and that loss is linked to how the material wears in service.

In tires, higher hysteresis means more energy lost, which affects wear resistance and traction, so compounders look for a balance rather than the lowest value. In O-rings, high hysteresis can make the ring wear faster and lose its sealing ability. In memory foam mattresses, a high value is exactly what the designer wants.

Because the meaning depends on the application, hysteresis is most valuable as a comparison: between candidate compounds, between a new batch and an approved one, or before and after a formulation change. Measured the same way every time, it fits ongoing quality control alongside abrasion and flex tests that address wear directly.

Elasticity is the ability to return to the original shape once the load is removed; hysteresis is the part of the input energy that does not come back. They describe the same deformation from two sides.

At rest, the long polymer molecules in rubber are compressed and twisted, and they straighten out under stretch. Most of the work goes into that change of shape, but some is lost as heat through friction between the molecules, so on unloading a band stays slightly longer at a given force than on the way up.

Hysteresis data from a hardness test therefore shows how elastic the material is and how quickly it recovers after loading.

Rebound resilience looks at the same behaviour from another angle: how much of a drop's energy the material returns. Our vertical rebound resilience testers cover foams, polyurethane and rubber compounds.

The VLRH (Very Low Rubber Hardness) testing scale is unique to the DigiTest II system. It follows the DIN ISO 27588 principle and is typically used for thin sponge-like material including: sponge- and foam rubber, cellular rubber, silicone, etc. The primary differences between the scales is that the VLRH can do indentations on thinner specimens of 2mm. It is kind of like a Micro Test Head for Shore 00 and 000, except that it offers added versatility of being able to test on concave and convex surfaces.

The measuring ranges are comparable based on their corresponding standards ASTM D2240 (Shore 00/000) and DIN ISO 27588 (VLRH).

The interval is set by your quality system and your customers' requirements. Because the measuring units are interchangeable, only the Shore, IRHD or VLRH heads need to come back to us for recalibration, not the electronic unit or the stand, and each comes back with a new certificate.

To avoid a gap in testing, we can send calibrated measuring devices on loan while yours are away. Send us the system serial number and the heads due, well ahead of the due date, and we will set out the cost of calibration and loan, the turnaround and the shipping instructions.

Between calibrations, the IRHD reference plates, standard rubber blocks in a stainless steel holder, maintain the metrological capability of the measuring device. For service under a maintenance contract, our contact page reaches the service team directly.

With the correct accessories, your Digi-test can absolutely double as an IRHD hardness tester.

For Shore D testing, a complete system includes the electronic unit and interface, a pick-up bracket with loading device, the Shore D measuring device, the indenter, the additional loading weights and any required certificates required to maintain your records.

With some additional sample holders such as the Barofix or Centrofix, measuring O-rings has never been more simple!

The Digi-test is commonly found in the rubber and plastics processing industries, automotive, chemical, cosmetics, food, aerospace, research centers and institutes, pharmaceuticals, medical technologies and optical industries.

Besides Shore A, the Digi-test with separate accessories can test Shore scales A, A0, B, 0, C, D, D0, 00, 000, 000 S, E, micro Shore A, micro Shore D, C, D0, IRHD/DIDC M, N, H, L, and VLRH.

The Digi-Test can accurately test Shore A as well as Micro Shore A. Shore A is designed for concave and convex molded parts of a material thickness of 4 to 6 millimeter. Micro Shore A is beneficial for those samples with a minimum thickness of 1mm.

The Digi-Test can test Shore D for measuring hard rubbers, semi rigid plastics and hard plastics. It also has the function of micro Shore D testing for samples with a minimum thickness of 1mm.

The Digi-test is commonly used for testing flexible mold rubbers that range in hardness from very soft and flexible through to hard materials with limited flexibility.

With Shore D, the recommended thickness of parts is 4 to 6 millimeter as it applies a very heavy load while measuring resistance to indentation.

The Digi-Test is a complete all in one solution, removing all human elements from your testing results, to provide the highest accuracy in quality assurance.

Shore hardness testing equipment is designed to measure a materials ability to resist indentation.

We happily provide calibration support, testing devices on loan during recalibration, testing services, maintenance contracts and in depth training.

There are a variety of scales for rubber testing with the Digi-test rubber shore hardness tester. Shore A, Shore D, Shore B, Shore C, Shore D0, Shore 00 and Shore 000. The specific scale will vary based on your specific material properties.

Besides exceptional support from pre-sale to after sale, we are happy to offer the official DKD/DAkks-Certificates for all exchangeable measuring devices on our Digi-test system.

The Digi-test meets the following international industry standards: DIN ISO 7619, DIN ISO 48, DIN EN ISO 868, NF EN ISO 868, ASTM D 2240, BS 903 Part. A 26, NF T 46-003, ASTM D 1415, DIN ISO 27588

Yes. For O-rings and other thin-walled parts the usual choice is the IRHD M measuring unit, which works down to a minimum material thickness of 0.6 mm and reports to ISO 48-2, the successor to DIN ISO 48, and ASTM D1415. On a ring the result is an apparent hardness, because the surface is curved.

Centering decides the result. The Barofix takes O-rings with a cord diameter of 0.6 to 5.0 mm, and the Barofix II, III and IV centre the ring automatically under the indenter; they work with the Digi Test II only.

The Barofix 4 adds optical detection on a movable table, measures ring thickness and height, and reads two positions on each ring, for rings 0.6 to 10 mm thick, with the IRHD M or Micro Shore A head.

Tell us the compound and the size of your rings, and we will recommend the head and the centering device.

For automatic bench testing our recommendation is the Digi Test II. It is built from four components: the electronic unit, the loading module, the test stand and an interchangeable measuring unit for Shore, IRHD or VLRH. Fitting a unit is plug and play: tighten the knurl nut and the electronics recognise the method and set the measuring time.

Results go out over USB, and our Hardtest software handles test and evaluation on any NextGen testing device with a serial interface.

For portable work or higher throughput, the HPE III portable durometer and the classic analogue durometer both mount on manual or automatic test stands, and the HDA 120 loads up to 20 samples for combined hardness and density checks. The full line is in our plastic hardness testing range.

Lead time depends on the configuration, so we confirm it with each quotation rather than giving one figure for every system. The main variables are the measuring units you choose, any centering devices such as the Barofix or Centrofix, custom sample holders and the certificates you need with the heads.

Standard sample holders and the positioning devices for tubes and O-rings are part of the regular range. A holder cut for your own part is scoped with our sales team before the order is placed, so allow for that step if your parts need one.

For a current date, send a request for a quotation listing the materials, the standard you report to and the scales you need. We will reply with the lead time for that exact configuration, along with the price.

The system covers rubber and plastics across the hardness range, and the measuring unit fitted decides which part of it. Highly elastic materials and soft rubbers run on the IRHD N/H/L units, while hard rubber, rigid thermoplastics, acrylic glass and polystyrene run on Shore D.

At the soft end, the Shore 00/000 and VLRH units handle foam rubber, sponge and cellular rubber, silicone and gel-like materials. Shore 0 suits soft elastic materials, pressure rolls and textile fabrics, and Shore B and C cover middle-hard rubbers and plastics.

For rubber, Shore hardness is reported to ISO 48-4, which replaced ISO 7619-1, and to ASTM D2240, while IRHD follows ISO 48-2 and ASTM D1415. For plastics and ebonite, the Shore method is ISO 868. Tell us the material and its thickness, and we will match the unit to it.

The German DAkkS certificate offered with each digital shore hardness tester. NextGen is partnered with the only company in Germany which has double identities, manufacturer and DAkkS calibration lab. This allows for a one-stop solution for your manufacturing and certification needs.

The main difference is how little the operator can influence the reading. The loading module applies the indenter instead of the operator's hand, and the electronic unit controls the method and the timing, so results stay repeatable from one operator and one shift to the next.

Automatic surface detection lets the system measure concave and convex surfaces as well as flat ones, and the indenter length can be customised so it reaches the point on the part that needs measuring. When a reading falls above or below the limit of the fitted unit, the display points you to a more suitable measuring device.

One stand carries the Shore scales, IRHD and the VLRH scale for very soft rubber, and the system can be integrated into an automatic production process. Before you commit, our testing service can measure your own specimens on the system.

Our automatic shore hardness testers are different from other manufacturing suppliers due to the production quality. What makes a Swatch different from a Rolex? After all, both give you very precise time indication.

Though we are not comparing ourselves to Rolex by price, we would like to make the bold statement that our equipment is the superior leader in quality production in the marketplace. All units are built with accuracy, user-friendliness, and maximum longevity in mind.

The IRHD and Shore Hardness Tester follow a variety of industry standards including:

DIN ISO 7619 / DIN EN ISO 868 / NF EN ISO 868 / ASTM D 2240 / JISK 6253 and more.

The display accuracy of the digital shore durometer system is to 1 digit after the decimal. Every machine comes standard with a DAkkS certificate which does a great job explaining all the mechanical tolerances. The superior accuracy of the unit gives our customers a peace of mind and the ability to achieve optimal measuring results every time.