Rubber Density & Physical Property Testing Equipment

  1. Home
  2. Rubber Testing Equipment
  3. Rubber Density & Physical Property Testing Equipment
Rubber Density & Physical Property Testing Equipment
Request Quote Get Catalogue

Density is one of the quickest checks that a compound matches its recipe and that one batch matches the last. It is measured on cured rubber, plastics and elastomers by weighing the specimen in air and in a liquid, and NextGen supplies density systems for this method working to ASTM D792, ISO 2781 and ISO 1183.

The range covers digital densimeters that read density and specific gravity directly, with storage and data output, and an automated station that handles hardness and density testing of a sample batch. Systems are installed and calibrated on site, your team is trained on the method and on handling specimens, and support continues for the life of the instrument.

Read More...

What Density Testing Measures

Density is mass per unit volume. For rubber it is found by weighing the specimen in air and again in a liquid, and the buoyancy method turns the difference into volume. It is one of the quickest checks that a compound matches its recipe and that one batch matches the last, and it is also used to estimate the mass needed for a target molded or extruded volume. In a rubber plant it serves as a check on compound consistency, filler loading and batch uniformity.

Standards for Density Testing

ISO 2781 covers solid vulcanized and thermoplastic rubber with two methods: Method A weighs the test piece in air and in water, and Method B uses a density bottle for cases where the sample must be cut into small pieces to remove trapped air, such as narrow-bore tubing. ASTM D792 covers density and specific gravity of solid plastics by displacement in water or in other liquids. ISO 1183 covers non-cellular plastics, and NextGen's standard page notes that the 1987 edition is withdrawn in favor of the newer series. The HDA 120 is listed under ISO 2781, DIN EN ISO 1183-1 and ASTM D1817 for its density measurement.

What Affects Density Results

Temperature control, the choice of liquid and the condition of the specimen matter as much as the resolution of the balance. A test piece should be smooth, crack-free and clean, bubbles and surface tension have to be controlled, and the supporting wire adds buoyancy error, which a large tank helps reduce. Floating specimens need a method to hold them below the surface.

Density Testing Equipment from NextGen

The NG-DM-A series digital densimeters work on the Archimedes buoyancy principle in five capacities from 150 g to 3000 g, with density precision of 0.001 or 0.0002 g/cm³. They display density, specific gravity, volume and mixture ratio, store ten groups of data and output over RS-232C. The HDA 120 combines three hardness readings with a density value per sample, weighing each sample in air and then under water, on up to 20 samples, and it is ISO/IEC 17025 certified. The densimeters also set high and low density limits that sound an alarm, track zero automatically and take a medium temperature from 0 °C to 49 °C.

For Laboratories

One partner to equip your complete rubber laboratory

Density testing is one station of an elastomer laboratory. NextGen equips the rest of it too, from tensile frames to cure testing, hardness, abrasion and specimen preparation, and stays responsible for it after delivery.

  • Equipment, fixtures and software
  • Installation, training, calibration
  • Lifetime technical support

Build My Rubber Lab

Products

2 products

Nothing matches that filter. Show all products

FAQs

ISO 2781 is the rubber method, for solid vulcanized and thermoplastic rubber. ASTM D792 covers solid plastics, and ISO 1183 covers non-cellular plastics. The densimeter and the HDA 120 are both listed under ISO 2781. Check which document your specification cites, and contact our team if it names a method for another material.

After the hardness readings, a pneumatic gripper moves the sample to a station where it is weighed in air, then immersed in distilled water by a rising water bath that moves up at least twice to remove air bubbles. The water level and temperature are checked for each measurement, and the highest wet weight is used. Density resolution is 0.001 kg/dm³, as listed on the HDA 120 page.

Solid mode reports density, specific gravity and volume of solid, granular and floating objects, and mixing ratio mode gives the content of a two-material mixture when both densities are known. The display also shows volume change rate, high and low limits can sound an alarm for sample qualification, and ten groups of data can be stored, including DIN volume abrasion loss. Output goes to a PC or printer over RS-232.

Water or other liquids can serve as the medium, and the medium temperature can be set from 0 °C to 49 °C. The medium density setting accepts values up to 19.999, and the instrument offers temperature compensation and air buoyancy compensation. It reads densities both above and below 1, so floating samples can be measured with the anti-floating frame supplied.

The models on the digital densimeter page differ in the weight they take and the precision they hold. NG-DM-A150 takes 150 g at 0.0002 g/cm³, NG-DM-A300 takes 300 g at 0.001, NG-DM-A600 takes 600 g at 0.0002, NG-DM-A1200 takes 1200 g at 0.001, and NG-DM-A3000 takes 3000 g at 0.001. The rest of the specification is common to the series.