What is Impact Test?
Impact Test is a process that applies a load to a sample at a very high speed and then evaluating the behavior of the sample. The breaking of a sample with the impact force can be done in two types using different testing machine. These types of tests involve two steps:
- The first step is to create a crack with a specific amount of energy and
- Secondly, apply more energy to enlarge the crack for the specimen failure.
Out of the mentioned two types of impact testing devices, the very first is the Izod/Charpy, and tensile impact that measures the actual amount of force or pressure absorbed by the sample to cause failure. Second type of test is the impact strength of the plastics with a free falling weight or dart impact test for the rigid materials and plastic films. These are usually Pass/Fail tests. They provide average impact energy to the sample that breaks the sample partially or completely. Out of mentioned test types, Dart Impact test is the widely recommended test for Plastic films and rigid plastics to test the resistance of impact on the materials.
As these tests are best for quality control, they provide appropriate information on the failure mechanism and cause of a fracture in an end use application. Whereas the non-instrumented impact tests measure the energy which is required to break the sample. The impact test provides a curve oh high-stress that distinguishes yield strength of the material from brittle failure to crack initiation and cracks enlargement. The graphical picture of the sample properties provides the clear image of the toughness of the specimen.
Best Ever Solution by Presto
Presto Stantest offers high-quality of Dart Impact Tester to measure the Impact of the free falling dart on the sample. The instrument is intended strictly in compliance with the national and international standards such as ASTM D 1709-15a, ASTM D 3029-82a, IS:8 E-177, IS:2508-1984
- ASTM D 1709 -15a – Standard Test Procedure to determine Impact Resistance of Plastic Film by Free-Falling
- ASTM D 3029-82a – Standard Test Procedure to determine Impact Resistance of Rigid Plastic Sheets by Free-Falling
- IS:2508-1984 – Defines the Specification for low-density Polyethylene Films
Specifications of Dart & Weight
As per the different standards of Dart Impact Tester, the test method is defined to test the impact resistance of thermoplastic films by the free falling dart. The standards describe two types of tests:
- First test explains, the dart of 38.10 ± 0.13 mm is employed with a hemispherical head which is dropped from a height of 0.66 ± 0.01 m. This method is used for films whose impact resistance requires the weight of about 50 grams to 2 kilograms to fracture the material.
- Second test explains, a dart of 50.80 ± 0.13 mm is employed with a hemispherical head which is dropped from a height of 1.50 ± 0.03 m. The range of impact applicability varies from 0.3 Kg to 2 kilograms.
Technical Specification of Instrument as per the Standards
- Specimen Clamp: It is designed with two pieces annular specimen clamp with inside diameter of 125 ± 2.0 mm.
- Electromagnet: The electromagnetic mechanism of the device is capable of supporting a 2-kilogram weight that efficiently supports and release the dart assemble efficiently.
- Collar – The inner diameter of the collar is 7mm (0.28 inch.) approximately. The collar is designed to the set screw. This helps to secure the collar to dart shaft.
- Darts – Darts for both Method A and B have hemispherical heads each with a shaft of 6.4mm diameter at 115 mm to appropriately accommodate removable incremental
- Voltage Requirement – Single Phase 5 Amp, 230 AC
- Dart Weight Big Size – 116 gm
- Dart Weight Small Size – 89 Grams,
- Outside Body – Mild Steel Duly Coated with Powder
- Vacuum Pump Power Supply – 230 VAC ± 10V AC/50 Hz.
- Vacuum Motor – ¼ HP
Presto Stantest design and manufacture high-quality of Dart Impact Tester by utilizing all the specifications and features that are mentioned in the standards.