(Hegewald & Peschke GmbH: Nossen, Germany) -- The Hegewald & Peschke GmbH automated hardness testing center fully automates hardness testing for quality assurance. One hardness testing system of this kind has now been installed at the site of an automotive supplier in Baden-Württemberg, where it measures the hardness of engine blocks quickly and reliably.
The new fully-automatic hardness test center of the Hegewald & Peschke GmbH improves the speed and reliability of testing due to its high test speed, a test evaluation that is independent from the operator, and its automatic registration of test results. It is possible to test complete product runs without the need for a person to manually evaluate the results.
The hardness testing system is designed as a modular construction and can be supplemented according to customers’ needs (e.g., with specimen processing modules or additional test systems for geometric measurements or for the determination of surface roughness). This increase the number of application areas to which the system can be applied. Apart from engine blocks, steel or aluminum wheels, and frame components, much more can be tested with this system because it can be adjusted to customers’ individual needs at any time.
For instance, a system for Brinell hardness testing of engine blocks consists of the following components:
• One Brinell hardness tester with an integrated, fully-automatic optical system for the measurement of the Brinell indentations. (The hardness tester applies a load of up to 3,000 kp with the help of a servo motor. For other specimens or materials, the system could substitute a Vickers or Rockwell hardness tester.)
• One ABB robot that can move and position specimens of up to 120 kg precisely
• One specimen preparation station that prepares the product surface for the test. (In this case it is a milling/grinding machine.)
• One identification station that registers the component’s labeling with the help of a camera system
• One marking station for the marking of the components. (As an alternative, a roughness measuring station could be substituted.)
• One feeding and storing device. (The design of this station depends on the specimen and performance.)
The specimen (in this example, an engine block) is transported to the hardness testing center. First, it is identified by the identification station that scans the serial number. Then the specimen is taken by the robot and positioned in the hardness tester, which carries out the fully-automatic Brinell hardness test. The engine block is moved to preset testing positions with the help of an X-Y cross table. After the measurements, the specimen is considered as either good or bad, which is registered by the identification station. Finally, the robot removes the engine block and puts it on a second conveyor which takes the block to packing or other processing units.
The automatic hardness testing center from Hegewald & Peschke GmbH can carry out high-precision quality assurance tasks on components and finished and semi-finished products. The robot is the central handling device for all tasks between the different stations. Before, these tasks had to be carried out by personnel, which took a lot of time and expense. Additionally, the automatic system eliminates errors caused by manual testing.
Depending on the customers’ needs, the automatic hardness testing center from Hegewald & Peschke uses either the Vickers, Rockwell, or Brinell hardness testing method. This allows for many different materials to be tested reliably. Due to the modular design it is also possible to substitute the hardness tester with a universal testing machine. This allows for the realization of fully-automatic tensile, pressure, and bending tests.
The Brinell method, developed in 1900 by the Swedish engineer, Johann August Brinell, utilizes a small carbide ball that is pressed with a certain load (depending on the material) for a certain time on the tested surface. The resulting indentation is then measured and put into relation to the applied load. The result of these calculations is the Brinell hardness value.
It has one deciding advantage: The Brinell hardness value can be converted easily to the tensile strength, which eliminates the need to produce tensile specimens that might be destroyed in the test.
The Vickers method is quite similar to the Brinell method. However, it uses a diamond penetrator, which is shaped like a pyramid instead of a carbide ball. Again, the indentation is measured and put into relation to the applied load to get the Vickers hardness value. In some cases, the dwell time is also included in the calculations.
The Brinell method is mostly used for the testing of very soft or medium-hard metals; the Vickers method is mainly used for very hard materials.
Since 1990, Hegewald & Peschke GmbH has been developing, producing and distributing high-quality machines, components, and software solutions for materials and component testing. The product range includes universal testing machines, hardness testers, component and furniture test stands, and different length measuring devices for research and industry. Highly qualified engineers and technicians not only carry out installations and calibrations of the testing machines, but they also do special instructions, training courses and maintenance work.
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