When testing machines are compared, they are verified according to different test standards. ASTM E4 – 14 is an important test standard when machines for force verification are considered. Test materials like rubber, metal and plastic need to be assessed for their tensile strength and compressive strength bearing capacity. Sometime before processing of materials and sometimes after processing, assessment of properties is important at every stage to control and manage the quality. To keep the whole process standardised many test standards have been rolled out and testing machines are made keeping the test processes in mind.
ASTM E4 -14
It defines the standard practice to measure the tensile strength and compressive strength, or both or testing machines that may or may not have force indicators. When a testing machine is analysed for force measurement, it complies with it and other related standards. But it is not the complete specification for complete purchase, it has to be one of the three related standards or combination of both. Everything that is incorporated in the machine like scales, displays, recorder charts are specified in the procedure. Parameters are measured in SI units, inch-pound units, this is to be regarded as the standard. Data which is displayed, stored, transmitted or delayed must comply with ±1% of accuracy, less than that is beyond standards and thus invalid. Machines or devices are used for force measurement must be highly calibrated.
At Presto, we work strictly in accordance with testing standards. ASTM E4 -14 is test process for force verification and all our tensile testing machine range is in compliance with it. This machine is exerting an outward force on the test material to a point where sample fails. How much force is required to deform it will be displayed on the screen. The tensile test is an important part of the quality management process.
Quality managers don’t leave an iota of the scope of product failure. When we say, testing a material, we are actually meaning to test the sample in lab conditions where the ambient temperature is controlled, humidity is known and other factors are completely in control. According to the intended use, the test sample is checked in a simulated environment. E.g. you are making a pulley for the conveyor belt. You have an approximate idea of the intended weight it has to bear. To check, if your rubber sample is capable of bearing that load you need a tensile tester. With the change in environmental condition, the pulley may change its properties become brittle when the temperature falls, but the whole assembly will not change every time temperature falls or rises, so your pulley should not break when it becomes brittle.
How to test the Tension bearing strength?
A tensile tester works simply on the principle of exerting an outward force on the sample to check if it can bear intended force or what is the maximum force required to break the sample. The machine is equipped with 2 jaws having grips attached to it. These grips can be chosen according to the test sample. The upper grip is stationary and lower grip moved downward to create tension. A sensor is attached to the load cell to calculate and display the force exerted. The force applied will be displayed on the digital screen.
Presto offers a varied range of tensile tester in manual, digital and computerised models. A universal tensile tester is a machine that can be easily interchanged for tensile testing and compression testing, buy just toggling the switch.
This model is quite flexible and can be easily customised for other purposes. E.g. Crown caps. Crown caps are usually used for sealing bottles with carbonated drinks that create pressure upon shaking. Bottles should not get opened accidentally. It can be modified for testing the integrity of crown bottle cap to test how much force is required to open it.
What other tests can be done in a similar manner?
Well, there is no end to the innovation. However, there are some other typical applications of tensile testing machine that requires applying outward force on the test material
- Bond strength testing
- Peel strength testing
- Adhesive strength testing
- Crimping strength testing
- Welded joint testing
- Tear resistance testing
- Elasticity testing