Automatic Charpy Machines
MPM’s pioneering technology development work over the past decade has resulted in the development of the world’s first fully automatic Charpy impact testing system. The machine receives test specimens from a multi-specimen magazine, reads the specimen ID via Vision System or user input, transfers the specimen to the anvils, centers the specimen, heats or cools the specimen to the desired test temperature (Single Specimen Mode), releases the pendulum, and records the encoder and/or instrumented striker data.
Test Machine Description
The automatic Charpy testing system can be installed on U-hammer and Z-hammer™ test machines of any desired energy capacity. The specimen transfer system will move one specimen at a time to the test machine. The optional Vision System allows the specimen ID to be read automatically, or the user can insert the specimens in the magazines in a desired order. For example, for nuclear and other applications where it is difficult to provide an ID on the test specimen, the data acquisition software will read the ID from the data base in the order the specimens are loaded in the fixture, or the ID can be input by the user at the time the specimen is transferred to the anvils for testing. Thus, the desired test temperature and other pertinent information are determined from a database stored on the data acquisition computer or via user input.
The Heating/Cooling system can configured in two ways: Batch Mode (for high specimen throughput) or Single Specimen Mode. In the Batch Mode, a thermal conditioning chamber is mounted near the anvils on the test machine and loaded with hundreds of test specimens. When the desired test temperature is reached, the specimens to be tested at that temperature are transferred to the anvils and tested in rapid succession. The Batch Mode works best when there are large numbers of specimens to be tested at a single temperature (e.g., 20 to 50 specimens at -55 ºC). The groups of specimens can be organized in the thermal conditioning unit so that the specimens are tested in the order of increasing or decreasing test temperature. This approach eliminates the loss of time due to the inertia of the thermal conditioning unit.
In the Single Specimen Mode, specimens are transferred from a multi-specimen magazine to the anvils one at a time and the patented MPM In-situ Heating & Cooling System will bring the specimen temperature to within 1ºC of the desired test temperature. The control system then moves the measurement thermocouple out of the swing path and releases the pendulum. The absorbed-energy data are automatically recorded and the cycle repeats until all of the desired specimens have been tested. For systems equipped with an optional instrumented striker system, the load-deflection data are recorded along with the encoder-measured total energy. Because the thermal inertia is low as compared with the Batch Mode system, the Single Specimen mode is the best choice when temperatures are different for each Charpy bar.
The automatic system can be provided with several options:
- Instrumented striker system
- Vision system for specimen identification
- Interlocked safety enclosure