Impact Testing Machines
Products > Impact Testers
Universal Grip supports Galdabini's full line of pendulum impact testing machines used for Charpy and Izod testing on plastic and metal samples. The machines are durable, safe, easy to use, and require virtually no maintenance besides annual calibration.
Impact resistance is one of the most critical material characteristics for engineers to consider when designing a metal or plastic component. The ability of a material to withstand repeated brunt schock forces is especially important for any sort of moving part used inside a machine. Impact testing is especially prevalent in the automotive and aerospace industries where product reliability and lifespan
Impact Testers are used to measure the resilience of a material. Resilience is defined as the amount of energy absorbed in impact by a material over a unit of volume. This value is usually given in Joules per cubic meter or J/m^3. Most impact resilience tests are performed on metal, however tests can also be performed on plastics and similar materials that exhibit both elastic and plastic deformation during testing.
Impact Testing with a pendulum striking arm is relatively simple in theory. Consider a frictionless system. When the pendulum hammer is at rest in the raised position, it has 100% potential energy, and 0% kinetic energy . The potential energy is given by: PE = mgh. Where m = mass(kg), g = gravity(9.8m/s^2) and h = height(meters).
When the hammer is released, the potential energy is transfered into kinetic energy . The system reaches 100% kinetic energy and 0% potential energy at the bottom apex of the swing. The specimen is struck at this point of maximum momentum and kinetic energy. The kinetic energy is given by: KE = .5mv^2. Where m = mass(kg), and v = velocity(m/s).
The hammer swings through to the other side until it reaches its maximum height. All of the kinetic energy is transfered back into potential energy at this point of maximum height. The impact tester uses an encoder to measure this height value of the arm after the impact. The post-test PE can be compared to the initial PE to find the amount of energy that was absorbed by the specimen during the test.
Universal Grip's Frank Bertini finishing a machine installation in Texas
Each impact testing system requires careful installation. The machine must be supported on a platform having at least 40 times the mass of the impact hammer. The platform base is also known as a plinth and is most commonly made of concrete. The plinth stabilizes the machine and can either be embedded into the floor, or more commonly, exposed above the floor.
Universal Grip provides the full solution for Galdabini impact testers. The plinth can be supplied along with a set of metail rails which sit underneath the cement platform. The metail rails have leveling screws which can be adjusted so that the machine rests flat on the plinth. These rails, the plinth, and the machine can be easily moved with a forklift.
There are several common accessories which are used for Charpy and Izod Impact testing. These accessories include broaching machines, chilling machines, and centering devices for sample placement. Along with these simple devices, Galdabini also has the engineering capability to design completely automated and roboticized test systems.
Broaching machines are also known as notchers and are used to place a precisely centered notch into the sample. Most samples are 10x10x50 rectangular bars.
Chilling machines have a refrigerated bath which is used to bring the specimen temperature down to -40 degree Celsius.
Sample placement tongs are used to pick the specimen out of the chiller and place it into the machine. According to the ASTM and ISO specifications, the operator has only 5 seconds to perform this action. A sample aligner is used in the machine to easily place the sample in the correct spot. The Galdabini Impact Systems also feature a button on the cabinet door which can be pressed to quicky initiate the test.
ASTM Impact Testing Procedures
The Universal Grip Company is the leading distributor of both Charpy and Izod impact testing machines in the USA. These premium machines are capable of both types of impact testing procedures. The impact testers have a motorized system for reloading the pendulum via a pushbutton which decreases the time in between test runs. ASTM E23 covers Charpy impact testing for metals, while ASTM D6110 involves plastics. Izod impact testing is slightly different than Charpy, although it still uses the pendulum testing mechanism and just requires a different impact hammer. Common ASTM Izod impact tests include ASTM D256 and ASTM D4812. The complete product line is listed below and the features are more or less universal between all of the machine sizes.
The Impact 150 Joule machine is a floor standing unit. The system can be configured for either Charpy or Impact testing by switching out the hammer. The system ships complete with a safety cage. The lexan paneled safety cage has a safety switch on the door which prevents an operator from opening the door unless the hammer is secured in the resting position.
The Impact 300 system can record up to 99 tests on non-volatile memory, so the test results will remain even if the machine is switched off. Test results can either be exported to a PC for additonal analysis and processing or can be sent to a printer. Test reports are slightly customizable and can include the operator name, absorbed energy value in Joules, Resilience Value in Joules/cm^2, a specimen identifier code, specimen temperature, and a timestamp.
The 450 Joule Impact machine utilizes a much larger hammer which is over 500 lbs. Because the size of the hammer is so large, it is not interchangeable between Charpy and Izod tests.
The impact 600 joule testing system requires the installation of a cement foundation of at least 1200kg. The foundation makes a stable base for the machine to rest on.
The Impact 750 is the largest machine and requires careful planning prior to purchase. The system can ship with optional PC software for data analysis and storage.