HDT Vicat Tester
Measure Thermal Resistance of Plastics Accurately
The Flexitest HDT & Vicat Softening Temperature Tester is designed to accurately evaluate the thermal performance and heat resistance of plastic and polymer materials. The HDT (Heat Deflection Temperature), also known as DTUL (Deflection Temperature Under Load), measures the temperature at which a test specimen deforms under a specified bending load.
During testing, the specimen is immersed in a temperature-controlled heating medium, with the temperature increased at a specified rate until the required deflection occurs. Vicat testing determines the softening temperature of materials under a specified load using a standard needle.
In the plastic and polymer industry, this machine is used to determine the exact temperatures at which materials begin to soften or deform under load ! The Heat Deflection Temperature (HDT) and the Vicat Softening Point. By revealing these critical thermal thresholds, it helps manufacturers select the right plastics that can withstand specific temperature conditions. This ensures products like car interiors, electrical housings, and outdoor equipment remain reliable and safe even when temperatures rise. Essentially, the HDT/Vicat Tester is vital for designing heat-resistant plastic products that perform flawlessly in real-world conditions.
Pendulum impact testers are versatile and reliable machines designed to fully comply with the specifications outlined in ASTM E23, EN10045-2 and ISO 148. Today, the Model IT406 and the Model IT542 are widely recognized as the standards of the industry for impact testing.
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Features
- Fully automatic control of the entire test cycle.
- Bath has port with an exhaust fan to remove interior oil fumes
- Pneumatic station lift for easy specimen insertion and removal
- Built-in specimen basket to catch any dislodged specimens
- 6 stations and 3 stations
- Built-in heat exchanger on 603 for rapid system cooldown
Technical Specifications
Select a model to view detailed specifications. Both models perform HDT and Vicat Softening Point tests as per ISO 75, ISO 306 and ASTM D648.
Model Comparison — VT3 vs VT6
Both models perform HDT and Vicat Softening Point tests as per ISO 75, ISO 306 and ASTM D648.
| Feature | HDVT3 3-Station | HDVT6 6-Station |
|---|---|---|
| Test stations | 3 | 6 |
| Test methods | HDT + Vicat | HDT + Vicat |
| Temperature range | 23 – 300 °C | 23 – 300 °C |
| Heating rate | 50 or 120 °C/hr (2°C/min) | 50 or 120 °C/hr (2°C/min) |
| Temperature resolution | 0.1 °C | 0.1 °C |
| Temperature sensor | Platinum RTD (per station) | Platinum RTD (per station) |
| Deflection / penetration | LVDT — 0.001 mm resolution | LVDT — 0.001 mm resolution |
| Bath capacity | 11 litres (stainless steel) | Larger bath (stainless steel) |
| Cooldown time | ~20 minutes | Rapid — built-in heat exchanger |
| Heat exchanger | Multi-wrap cooling coil | Built-in heat exchanger (faster) |
| Pneumatic station lift | ✓ Yes | ✓ Yes |
| Exhaust fan (oil fumes) | ✓ Yes | ✓ Yes |
| Specimen basket | ✓ Yes | ✓ Yes |
| Fully automatic cycle | ✓ Yes | ✓ Yes |
| Software | Horizon (standalone or PC) | Horizon (standalone or PC) |
| Power supply | 220/240 V, 50/60 Hz, 4.5 kW | 220/240 V, 50/60 Hz |
| Best suited for | Smaller labs, R&D, low throughput | Production labs, high throughput |
Technical Specifications
| Parameter | Value / Detail |
|---|---|
| Standards | ISO 75 · ISO 306 · ASTM D648 · ASTM D1525 |
| Temperature range | 23 °C to 300 °C |
| Heating rate | 50 °C/hr or 120 °C/hr (2 °C/min) |
| Temperature resolution | 0.1 °C |
| Temp. sensor (per station) | Platinum RTD + safety overtemp switch |
| Deflection measurement | LVDT — 0.001 mm resolution |
| HDT load (ISO 75 flatwise) | 0.45 MPa (76 g nominal on 4 × 10 mm specimen) |
| Vicat needle area | 1 mm² flat-ended; penetration depth 1.0 mm |
| Edgewise anvil span | 100 mm (standard) |
| Flatwise anvil span | 64 mm (optional, pre-drilled) |
| Bath medium | Heat transfer fluid (silicone oil) |
| Bath capacity (VT3) | 11 litres (stainless steel) |
| Cooldown time | ~20 min (VT3) · Rapid with heat exchanger (VT6) |
| Data acquisition | 1000 Hz via RJ-45 PC connection |
| Control / display | Colour touchscreen LCD; stored protocols; SI / metric / English units |
| Results | Average + standard deviation; auto-zeroing; real-time display |
| Air supply (pneumatics) | Clean dry air, 50 µm filter, 40 psi (2.7 bar); supply 65 psi |
| Power supply | 220/240 V · 50/60 Hz · 4.5 kW ±10% |
| Dimensions (VT3) | 585 mm (H) × 813 mm (W) × 635 mm (D) |
| Weight (VT3) | 87 kg |
* VT6 dimensions and weight may differ. Contact Flexitest for model-specific datasheet.
Technical Specifications
Select a model to view detailed specifications. Both models perform HDT and Vicat Softening Point tests as per ISO 75, ISO 306 and ASTM D648.
FAQ's
What is a Heat Deflection Temperature (HDT) test?
The Heat Deflection Temperature (HDT) test measures the temperature at which a plastic specimen deflects by a fixed amount under a constant load. It tells you how well the material maintains its shape and structural rigidity when exposed to elevated temperatures -critical for applications like car interiors, electrical housings, and outdoor equipment.
What is a Vicat Softening Point test?
The Vicat Softening Point test measures the temperature at which a plastic specimen is penetrated to a depth of 1 mm by a flat-ended needle under a defined load. It indicates the temperature at which the plastic begins to soften significantly -an important parameter for moulding, forming, and application design.
What is the difference between HDT and Vicat tests?
HDT measures the temperature at which a bar specimen deflects under a bending load -it evaluates structural stiffness under heat. Vicat measures penetration of a needle into the surface -it evaluates the onset of softening. Both tests are used to determine the upper service temperature of plastics, and many labs run both on the same machine.
Which standards does this tester comply with?
What models are available -VT3 and VT6?
Yes, the tester is available in two configurations:
- VT3 (3-station) -tests 3 specimens simultaneously; suited for smaller labs or lower throughput
- VT6 (6-station) -tests 6 specimens simultaneously; suited for production labs and higher throughput
The 6-station (603) model also includes a built-in heat exchanger for rapid cooldown between test runs.
What is the fully automatic test cycle?
How does the pneumatic station lift work?
What materials can be tested with this machine?
The HDT / Vicat tester is designed for plastics and polymers, including thermoplastics (PP, PE, ABS, PVC, Nylon, Polycarbonate, PET, PBT), thermosets, composites, and polymer blends. It is used across automotive, electrical, packaging, and consumer goods industries to verify thermal performance.
Does Flexitest provide installation, calibration and after-sales support?
How do I get a quote or download the brochure for the HDT / Vicat tester?
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