CEAST - Heat Deflection Temperature and VICAT Testing

Understanding HDT and Vicat Testing: Key Methods for Assessing Thermal Properties of Plastics

HDT (Heat Deflection Temperature) and Vicat testing are crucial methods used in materials science to evaluate the thermal properties of polymers and plastics. These tests help manufacturers and researchers determine how materials will perform under heat stress, making them essential for quality control, product development, and compliance with industry standards.

HDT Testing: Heat Deflection Temperature

HDT testing measures the temperature at which a polymer deforms under a specified load. This test is particularly important for applications where materials will be subjected to high temperatures, such as automotive, aerospace, and consumer goods.

Test Procedure:

1. Sample Preparation: Specimens are typically prepared in standardized shapes, often as rectangular bars.
2. Loading: The specimen is subjected to a defined load, commonly 1.82 MPa (264 psi), which simulates operational conditions.
3. Temperature Increase: The sample is heated at a controlled rate, usually around 2°C per minute.
4. Deflection Measurement: The temperature at which the specimen deflects a specified amount (usually 0.25 mm) under the load is recorded as the HDT.

Significance: The HDT provides critical information about the temperature range in which a material can safely operate without significant deformation. This data helps engineers select materials that will maintain their structural integrity in high-temperature environments.

Vicat Testing: Vicat Softening Point

Vicat testing measures the softening point of a polymer, providing insight into how it behaves under heat. This test is particularly useful for understanding the temperature at which a material transitions from a rigid state to a more pliable one.

Test Procedure:

1. Sample Preparation: Similar to HDT, specimens are prepared in standardized shapes.
2. Loading: A needle or ball is placed on the specimen, applying a specific load (typically 1 kg for the Vicat test).
3. Temperature Increase: The sample is heated at a controlled rate, generally around 50°C per hour.
4. Softening Measurement: The temperature at which the needle penetrates the sample to a specified depth (usually 1 mm) is recorded as the Vicat softening point.

Significance: The Vicat softening point is critical for applications where materials may experience varying temperatures during processing or service. It helps in assessing how materials will perform during manufacturing processes such as molding and extrusion.

Standards and Compliance

HDT and Vicat tests are governed by several international standards, including:

• ASTM D648: Standard Test Method for Deflection Temperature of Plastics Under Flexural Load.
• ASTM D1525: Standard Test Method for Vicat Softening Temperature of Plastics.
• ISO 75: Plastics—Determination of temperature of deflection under load.
• ISO 306: Plastics—Determination of Vicat softening temperature.

Instron HV Series: Enhanced HDT and Vicat Testing Machines

The Instron HV Series of HDT (Heat Deflection Temperature) and Vicat testing machines delivers an elevated user experience and outstanding productivity, making materials testing simpler, smarter, and safer. Equipped with Bluehill® HV Software, these machines are designed to streamline the testing process and enhance laboratory efficiency.

Key Features

1. Ergonomic Design: The HV Series features an ergonomic testing station with a smooth lifting mechanism and comfortable handles. This design ensures that operators can safely and easily raise and lower the testing apparatus, minimizing physical strain.
2. Intuitive Weight Application: The intuitive weight design reduces the risk of selection mistakes. The stackable weights allow users to confidently achieve a wide range of stress values without the need for additional tools, simplifying the setup process.
3. User-Friendly Touch Screen Interface: The HV Series is equipped with a user-friendly touch screen interface, allowing for quick and easy setup of HDT and Vicat tests, as well as data export. Pre-formatted templates enable users to initiate tests with just a few taps, making the process efficient and accessible.
4. Effortless Workflows: The optional Bluehill HV Software enhances usability, enabling users to run tests, edit methods, analyze results, and configure the system with minimal effort. This software dramatically increases laboratory efficiency and throughput.
5. Oil Degradation Control: The system continuously monitors oil levels and alerts users when the bath level is out of range or when oil degradation occurs. This proactive feature reduces the risk of invalid test results and enhances overall productivity.
6. Efficient Cooling System: Designed for superior cooling efficiency, the HV Series rapidly returns the oil to its starting temperature after each test. This capability minimizes wait times between tests and helps reduce water consumption costs.
7. Advanced Electronic Technology: The HV Series incorporates advanced electronics that automatically zero the position of the LVDT (Linear Variable Differential Transformer) measuring sensors before each test. This feature not only reduces test time but also minimizes human errors.
8. Compact Footprint: The compact design of the HV Series maximizes valuable laboratory space, allowing for enhanced testing efficiency without sacrificing performance.
9. Superior Results and Repeatability: Comprehensive verifications by factory-trained engineers ensure that critical components and temperature behaviors are accurately assessed, leading to reliable and repeatable results.
10. Protection of the Test Area: The HV6X model features a full shield that restricts access during test execution, protecting users from moving parts. This design is ideal for open-access workplaces where multiple testing instruments may be in use.
11. Secured Test Access: Bluehill HV Software secures test methods to prevent inadvertent changes, ensuring repeatability and compliance with standards across multiple shifts and operators. The software allows for the creation of specific user profiles tailored to each operator’s level of expertise.
12. Maximum Temperature Control: The built-in temperature control system limits the maximum temperature of the oil bath, conforming to specifications for each oil type. This feature prevents dangerous fumes and inaccurate test results due to improper temperature settings.
13. Effective Training Program: Instron engineers provide comprehensive on-site training courses to enhance operator safety, improve efficiency, and optimize system capabilities, all while supporting the laboratory’s health and safety policies.