Hegewald & Peschke GmbH automates quality assurance

Oct. 28, 2009 - PRLog -- - Modular solution: Conceptual design according to customers’ needs
- Customer success: Fully-automatic 100 % testing of engine blocks according to the Brinell method

Nossen, 28th October 2009 – The Hegewald & Peschke GmbH automates quality assurance. For this task, the company designed a robot-based hardness testing system, which serves to measure the hardness of components and finished products in a fully-automatic way. 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 centre of the Hegewald & Peschke GmbH invigorates the industrial quality assurance due to its high test speed, the test evaluation independent from an operator, and its automatic registration of test results. Thus, it is possible to test complete product runs without the need for a person to evaluate the results manually.

Customer-specific hardness testing
The hardness testing system is designed as a modular construction and can be supplemented according to customers’ wishes, e.g. with specimen processing modules, or additional test systems (for instance, for geometric measurements or for the determination of the surface roughness). This develops multiple application areas in the section of quality assurance. Apart from engine blocks, steel or aluminium wheels, frame components, and 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 the 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 3000 kp with the help of a servo motor. For other specimens or materials the system could also be substituted by a Vickers or Rockwell hardness tester.)
- One ABB robot, which can move and position specimens of up to 120 kg precisely.
- One specimen preparation station, which prepares the product surface for the test.
(In this case it is a milling / grinding machine.)
- One identification station, which registers the component’s labelling with the help of a camera system.
- One marking station for the marking of the components.
(As an alternative, this could also be substituted by a roughness measuring station.)
- One feeding and storing device.
(The design of this station is depending on the specimen and performance.)

Example of a test run with the automatic hardness testing centre
The specimen is transported to the hardness testing centre. First, it is identified by the identification station, which 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 pre-set testing positions with the help of an X-Y cross table. After the measurements, the specimen is considered either as good or bad block which is registered by the identification station. The robot is responsible for all the handling of the process. Finally, the robot removes the engine block and puts it on a second conveyor, which takes the block to packing or other processing units.

Performance and application of the fully-automatic hardness testing centre
The automatic hardness testing centre from Hegewald & Peschke GmbH can carry out high-precision quality assurance tasks on components, 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 expenses. Additionally, the automatic system eliminated errors that were caused by the manual testing.

Depending on the customers’ needs, the automatic hardness testing centre from Hegewald & Peschke uses either the Vickers method, the Rockwell, or the Brinell 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 or supplement the system with one. This allows for the realisation of fully-automatic tensile, pressure, and bending tests.

The Brinell method
The Brinell method has been developed in 1900 by the Swedish engineer Johann August Brinell. Since then, the method has been used to determine material hardness values and, by now, it has become a standard method, which can also be automated. The basic principle of this method is a small carbide ball, which is pressed with a certain load (depending on the material) for a certain time on the tested surface. The resulting indentation, which looks like a ball scraper, is then measured and put into relation to the applied load. The result of these calculations is the Brinell hardness value (HBW).

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 which might be destructed in the test.

The Vickers method
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 (HV). In some cases, the dwell time is also included in the calculations.

Both, the Brinell and the Vickers method are not applied to special test specimens and avoid a possible destruction of the parts. However, both methods vary in the used materials: The Brinell method is mostly used for the testing of very soft or medium-hard metals. On the other hand, the Vickers method is mainly used for very hard materials.

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About Hegewald & Peschke Meß- und Prueftechnik GmbH:
The measuring and testing technology specialists are based in Nossen, near Dresden. The company has been developing, manufacturing and selling high-quality machines, components and software solutions for testing raw materials, constructional elements and components. These include universal testing machines, hardness testing machines, test stands for furniture and constructional elements, as well as various length measurement devices for industry and research. The design and software development divisions at Hegewald & Peschke maintain close cooperation with universities and research institutes (such as Fraunhofer) in order to ensure that the company’s products remain at the cutting-edge of technology. Hegewald & Peschke is certified under ISO 9001 and has its own DKD calibration laboratory. For further information about Hegewald & Peschke Meß- und Prueftechnik GmbH, please refer to the website www.hegewald-peschke.com.