This regularly published info letter reports the state-of-the-art and new trends in acoustic testing technology. You can subscribe to this letter by sending a mail to newsletter(at)rte.de
Secured Snap-in of Plug-in Connectors
Even in the age of bus technology, plug-in connections are still very often used. Especially in the automotive industry, where the number of electronic devices is fast-paced, many sensors are connected with evaluation and control boxes by wires and plugs.
To avoid the accidental dismantling of this connection caused by shock or vibration, the plugs snap in a coupling using a plastic or metal clamp insofar as they are fitted completely mechanically. An electrical check does not guarantee safety, because the electrical contact normally exists before the mechanical snap-in. Additional manual tensile tests do not assure complete safety either and are very costly. Acoustic control of the snap-in noise in automatic assembly lines is possible during the manufacturing process. Special methods can reliably control and evaluate these very short peaks. The results can be stored and used for the documentation of the assembly.
You have such a problem? You can discuss the procedure for a solution personally with the experts from RTE at the CONTROL exhibition in Sinsheim, Germany, in hall 4, booth 4411.
Avoiding Vibration: The Well-fitted Steering Columns According to Type of Car
Delphi Polska Automotive Systems has installed two test stands to measure the natural frequencies of manual and power column. This allows Delphi to classify the columns before they are built into a car. If the resonances of the column are not in the suitable range for the type of the car, then it is possible that the steering wheel vibrates unpleasantly, e. g. when the engine is running idly.
The assembly conditions of the clamping force, the mounting angle and the steering wheel are simulated in the test bench. Two electro-dynamic impact devices stimulate the steering rack in different directions. The test system SR20AT from RTE measures the natural frequencies through two solid-based accelerometers accurate to a Hertz and generates a label according to the class allocation. This allows Delphi to deliver car-type specific steering columns to the car manufacture, who can provide maximum comfort to his customers. For detailed information please contact Ingolf Hertlin from RTE (I.Hertlin(at)rte.de).
Steering column mounted in test bench fixture (yellow: clamps, on the right: excitation and sensors)
Interesting Exhibitions in the 2nd Quarter 2005
A lot of interesting shows take place in the second quarter of every year. The German “Ausstellungs- und Messeausschuss der deutschen Wirtschaft e.V. (AUMA)” publishes a very good overview in the Internet under www.auma-messen.de with many interesting links and search functions.
Particularly for quality assurance the following shows are interesting:
02 -04 May:
Annual meeting of Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP) in Rostock (www.dgzfp.de)
10 -12 May:
Sensor + Test – 12th International Exhibition (http://sensorfairs.nuernbergmesse.de)
Automotive Testing Expo 2005, Stuttgart (www.testing-expo.com)
08 -10 June:
Austrotec 2005 – Production and Automation, International Congress und Exhibition, Graz (Austria) www.messe-graz.at. RTE booth 207
Mobile Measuring Technology for Acoustic Material Testing
Having introduced the universal laboratory testing station in our last info letter, today we would like to present the mobile version for quick on-site use or for random testing.
The magnetically adhesive work piece fixtures and the measuring components for acoustic testing of smaller work pieces are integrated in a robust case. The work piece fixtures can be adapted to various work pieces. The excitation of the test object takes place manually. The comprehensive software package SR20AT offers numerous versatile possibilities for presentation and documentation and runs on a notebook. You are welcome to test the mobile version at the CONTROL exhibition in Sinsheim.
Acoustics in the Internet: Vibration Decoupling
By structure-borne noise we understand all sound waves dispersing in solid bodies. Massive components relay the sound waves as structure-borne noise. insulation of structure-borne noise is concerned with measures which reduce the oscillation of transmissions from one component to another.
In order to carry out reproducible acoustic measurements in manufacture, appropriate insulation elements will have to be provided. These serve to decouple the testing fixture from the disruptive oscillations. A great number of insulating elements is on offer. The manufacturers provide an advisory service to achieve the optimum solution.
In principle it may be said that the insulation of low disruptive frequencies requires a considerably higher expenditure than the insulation of higher frequencies.
On the Internet address www.schwingmetall.com/ there is a very detailed technical description concerning the problem, also with calculation examples. Additional interesting pages are e.g. www.elastometall.de or www.fabreeka.de.