NG-HDT – HDT/Vicat Testing Machine for Plastics

On the bench, the NG-HDT measures 50.4 × 20.9 × 31.5 in (1280 × 530 × 800 mm), length by width by height. Allow room for the door as well: with it open, the envelope grows to 50.4 × 24.4 × 49.6 in (1280 × 620 × 1260 mm), so keep clear space above and in front of the unit. The machine weighs 353 lb (160 kg).

It runs on a single-phase 220 V AC supply (±10%, 50 Hz ±2%) with 3.5 kW power consumption. The installation also needs water inlet and outlet connections for the standard water cooling, and the pipes, rated to 300°C (572°F) and 78.7 in (2 m) long, ship with the machine. A LAN port and two USB 2.0 ports handle data connections.

If the lab has no suitable bench, we can supply a work bench of 55.1 × 25.6 × 29.1 in (1400 × 650 × 740 mm). Installation and training come with our lab projects, so talk to our team about the room before delivery and we will check space, power and water with you.

HDT and Vicat results show how a plastic behaves as it heats up under load, but a qualification file rarely stops there. When we equip a plastics lab, the thermal system is planned alongside a melt flow indexer for flow behaviour, universal testing machines for tensile and flexural properties, and impact and falling weight testers for toughness.

Hardness and durometer systems and environmental chambers are part of the same lab projects, so a single plastics lab can cover thermal, mechanical, flow and hardness checks under one roof.

Because all of these come from NextGen, the lab works with one partner for installation, training, calibration and support for the life of the equipment. See how we equip complete laboratories, or send us the standards your material program has to meet and we will map the equipment to them.

For Vicat softening temperature, the NG-HDT works to ASTM D1525, ISO 306, the ISO 2507 series for thermoplastic pipes and fittings, GB/T 1633 and GB/T 8802. All five are stored as preset methods on the touchscreen.

For heat deflection temperature, it covers ASTM D648 and ISO 75 Parts 1, 2 and 3, together with GB/T 1634.1, GB/T 1634.2 and GB/T 1634.3. ASTM D648, ISO 75-2, ISO 75-3, GB/T 1634.2 and GB/T 1634.3 are preset. ISO 75-3 and GB/T 1634.3 apply to high-strength thermosetting laminates and long-fibre-reinforced plastics, and they run with a custom stress value and the optional adjustable-span support.

Each method still depends on the edition, the specimen and the condition set your test plan names. If a purchase specification cites one of these documents, include the edition and the condition set with your enquiry and we will match the spans, loads and weights to it.

Each test station has its own LVDT displacement sensor, so the NG-HDT300 carries three and the NG-HDT600 carries six. In an HDT run the sensor tracks deflection of the bar under the loading nose, and in a Vicat run it tracks penetration of the needle, while the bath temperature rises.

Resolution is 0.001 mm and accuracy is better than 0.01 mm over a 15 mm measuring range. That margin matters at the end of a test, because the result is the temperature at which a specified deflection or penetration is reached, and a fine reading lets the system catch that point as it happens.

The endpoint is detected by the instrument, not read off a dial by an operator, which removes one source of difference between operators and shifts. Displacement and temperature are stored with each test, so earlier runs can be searched and reviewed later.

Two linear heating rates are built in: 120 ± 10°C/h (216 ± 18°F/h) and 50 ± 5°C/h (90 ± 9°F/h). The selected rate is held while the specimens stay under constant load, and the temperature at which each one reaches its endpoint is the test result.

The two rates are the ones the common Vicat and HDT condition sets are built on. ISO 306, for example, groups its conditions as A50, B50, A120 and B120, each a combination of load and heating rate, so both rates are needed on the same machine.

The rate is set by the method chosen on the touchscreen, so nobody adjusts heating by hand during the ramp. Once the endpoint is reached, the run moves on to unloading and cooling without operator steps, which keeps the procedure identical from batch to batch.

The NG-HDT measures two temperatures that describe how a thermoplastic softens as it heats under load: heat deflection temperature (HDT) and Vicat softening temperature (VST). Both tests run on the same platform, so a lab covers them without a second instrument.

The materials are thermoplastics, including plastic pipes and fittings. Labs use the results in product qualification, incoming inspection and material comparison, which puts the machine in routine QA/QC work as well as in material development.

A run is automatic from start to finish. The system loads the specimens, ramps the bath at the selected rate, records deflection or penetration, then unloads and cools so the next batch can go in. With three or six stations, several specimens are tested in one heating cycle, and results can be reviewed, searched and exported over Ethernet.

The oil bath runs from ambient temperature up to 300°C (572°F) and holds 4.76 gal (18 L). Specimens are tested in this immersion bath, so the oil carries heat to every station during the ramp.

Holding the ramp steady across that span depends on the bath design. The NG-HDT bath uses turbulence suppression and cyclic heating, which keep heating conditions steady while the temperature climbs through the test.

Cleaning is quick. The open-type oil tank is released with knobs and can be cleaned in about five minutes, and the modular specimen rack lifts out without tools, so fragments from a dropped specimen can be cleared between runs.

There are two models. The NG-HDT300 has three test stations and the NG-HDT600 has six. Temperature range, heating rates, displacement measurement, bath, power, weight and footprint are the same on both, so the choice comes down to how many specimens you test in each heating cycle.

Station-specific parts scale with the count. Each station has its own support span, HDT loading nose, Vicat needle, LVDT sensor and universal weight set, and the machine carries four temperature sensors on the three-station model and seven on the six-station model. The optional Vicat weight set is ordered one per station.

Pick the count against your expected volume: the six-station model doubles the specimens per run, which matters when HDT and Vicat batches queue up. Request a quote for either model with your weekly test volume and standards, and we will price the matching station kit.

Both tests heat a specimen at a controlled rate under a constant load. They load it differently, though, and so they report different temperatures.

In HDT, a bar sits edgewise on a support span and a loading nose applies a set flexural stress while the bath heats. The result is the temperature at which the bar reaches the specified deflection. On the NG-HDT the stress is set to 1.80, 0.45 or 8.00 MPa for ISO 75-2 and GB/T 1634.2, or to 0.455 or 1.82 MPa for ASTM D648.

In Vicat, a needle presses on the specimen under a 10 N or 50 N load, and the result is the temperature at which it reaches the specified penetration. Vicat is the method written into the pipe and fitting standards, such as GB/T 8802 and the ISO 2507 series.

Our article HDT and Vicat: Two Softening Temperatures That Answer Different Questions sets the two methods side by side.

Every NG-HDT ships with its three or six test stations. Each station is fitted with a support span, an HDT loading nose of R 3.0 ± 0.2 mm, a Vicat needle of 1.000 ± 0.015 mm² cross-section, an LVDT displacement sensor and a universal weight set that combines up to 5500 g (12.1 lb) in 1 g steps.

The base unit includes the immersion oil bath, four or seven temperature sensors and a built-in 10.4 in industrial PC with capacitive touchscreen, running our GenTest software in English.

Handling tools are in the box: tweezers, specimen scissors, specimen separating pliers, a specimen box, 1.5 mm and 2.5 mm wrenches, an oil filling funnel and the inlet and outlet water pipes. For calibration you get gauge blocks of 2 mm, 3 mm and 2 × 4 mm, and the machine has a Φ3.2 mm temperature calibration hole for an external thermometer.

A quality certificate and the operation manual on a USB drive complete the delivery.

Yes. The touchscreen control system includes preset method options and supports custom methods for internal procedures or customer-specific requirements. This helps labs run routine standards-based testing while keeping flexibility for special material programs or non-standard evaluation work.

For mixed-method labs, request a quote with the required standards listed.

The system supports water cooling, and an optional chiller is available for faster cooldown. With the chiller option, the bath can cool from 392°F to 73°F (200°C to 23°C) in about 45 minutes, depending on operating conditions.

If faster turnaround is important for your lab, request a configuration quote with the cooling option included.

The system uses Class A PT100 temperature sensing. This supports stable temperature measurement during the controlled heating cycle, which is critical for repeatable HDT and Vicat results.

For labs comparing older equipment against current requirements, ask us to review the setup.

The standard configuration supports common HDT and Vicat specimen formats, including 2.52 in (64 mm), 3.94 in (100 mm), and 4.00 in (101.6 mm) support spans depending on the selected method. It also includes HDT loading noses, Vicat needles, gauges, and related tooling for routine operation.

If your specimens require a non-standard span or fixture setup, send us the details.

Optional accessories include universal weight sets, Vicat weight sets, automatic cooling, oil vapor extraction and filtration, nitrogen protection, computer options, and related items for specific lab requirements.

If you already know your standards, station count, and throughput target, request a detailed quote.

The NG-HDT includes a closed shield, door lock, dual overheat protection, oil-level monitoring, overflow protection, lift obstruction protection, pressure relief protection, and a lockable oil outlet. These features help protect the operator, specimens, oil bath, and mechanical system during heating, testing, unloading, and cooling.

For high-throughput labs, ask about safety and workflow configuration.