charpy Impact Test Equipment Plastic Charpy Pendulum Impact Tester Impact Testing Instrument

Testing Machine Specification:

I. Principle of Charpy Impact Test

1. Definition and purpose

-Principle of the test. 

Principle of the test: The impact toughness (resistance to brittle fracture) of a material is evaluated by measuring the energy absorbed by fracture of a horizontally placed notched specimen by means of a pendulum dropping freely to impact the specimen.

Applicable materials: plastics (e.g., ABS, PC, nylon), metals, composites, etc.

Core standards:

ASTM D6110 (Charpy impact test for plastics)

ISO 179-1 (Determination of Impact Properties of Plastic Simply Supported Beams)

GB/T 1043 (Chinese national standard).

2. Differences from the Izod test

Parameters

Charpy impact test

Izod impact test

Specimen clamping method

Simply supported beam (horizontally supported, notch back to pendulum)

Cantilever beam (vertical clamping, notch facing the pendulum)

Notched position

Center of specimen (one side notched)

One end of the specimen (one-sided notch)

Unit of energy calculation

Impact strength (kJ/m2)

Impact strength (J/m or ft-lb/in)

Applicable Standards

More widely used in European and Chinese standards

More commonly used in North American standards (ASTM D256)

Second, Charpy pendulum impact tester design

1. equipment composition

Pendulum system: adjustable energy (0.5-50 J), the pendulum pre-lift angle is usually 150 °.

Specimen support: two points to support the specimen, the span is usually 40 mm (plastic test).

Energy measuring device: Pointer or digital display to record the energy loss with an accuracy of ±1%.

Safety shield: splash-proof against debris, equipped with interlocking device.

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Optional modules:

High and low temperature environment box: test the impact performance of materials at -60℃~+150℃.

Automatic sample feeding system: to enhance the testing efficiency (suitable for large quantity testing).

2. Plastic specimen requirements

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Standard size: 80×10×4 mm (ISO 179-1), with V-type or U-type notch machined in the center (notch depth 2mm).

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Notch machining: use a special milling cutter to ensure that the bottom of the notch is smooth and burr-free.

Third, the plastic impact test process

1. 

Specimen preparation:

Injection molding or cutting standard specimens, machining notches (need to meet the standard size).

Pre-treatment of specimens (e.g., 24 hours at 23°C/50% RH environment).

2. 

Equipment calibration:

Check the no-load energy loss of the pendulum (should be ≤1%).

Calibrate the energy scale to ensure accurate zero point.

3. 

Specimen mounting:

Place the specimen horizontally on the support with the notch back to the direction of the pendulum impact.

4. 

Test execution:

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Release the pendulum to impact the specimen and record the fracture energy value.

5. 

Result Calculation:

Impact strength

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: fracture absorption energy (J)

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: Specimen width (m)

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: remaining thickness of the specimen (m)

IV.Key factors affecting the test results

Factor

Description

Notch precision

Notch shape (V-type/U-type), depth error needs to be ≤ 0.1mm, otherwise the data deviation is significant.

Temperature and humidity

Low-temperature testing requires the use of an environmental chamber (e.g. -30℃), and high-temperature testing requires protection against thermal expansion of the pendulum.

Specimen orientation

The molecular orientation of the injection molding material (parallel/perpendicular flow direction) may lead to differences in the results and should be clearly marked.

Pendulum energy selection

Too high an energy will result in complete breakage of the specimen, too low an energy will prevent breakage, a reasonable range should be estimated according to the material.

V. Suggestions for equipment selection

1. Core parameters

Energy range: according to the material impact strength selection (general-purpose plastics selection 0-25 J, engineering plastics selection 25-50 J).

Precision requirements: digital display type is better than pointer type, resolution of 0.1 J, accuracy ± 1%.

Extended functions: high and low temperature module, automatic sample feeding system, data management software.