technical article 2018 No.2
Patented process from Switzerland
Metal relax with vibration
Technology as an alternative for stress
MEMV® is a method of Swiss WIAP AG with several patents. The "Metal relax with vibration" can be used as an extension to stress relieving or even replace these energy-intensive technology in many cases. The purpose of both methods, stresses and distortion at components - about as a result of welding operations - balance.
Stress relieving is applied to relieve internal stresses. Here, the steel is heated in an energy-intensive process using an annealing furnace at 500° C to 600° C; characterized the yield strength decreases. All tensions that were previously at room temperature on the yield strength will now be reduced to the lowered yield. However, the annealing temperature may not be achieved in quenched and tempered steels. In addition, a stress of stainless steels in the temperature range of approximately 500° C to 650° C is to be avoided sweeping,since the susceptibility to intergranular corrosion increased significantly here or entering through elimination of unwanted hard phases embrittlement of the material.
The WIAP AG Ltd SA, based in Dulliken calls her metal relaxation method using vibration MEMV®. If Swiss specialists expand the decades consistently used method VSR. When "VSR-vibrate" a vibrator is located at a certain position of the component and excites a direction. After about 30 minutes, the variation of the amperage and the G value is determined (1 G = 9.81 m/s2), which were observed during the process. Also, the walking of the translating self-resonance point of a speed range at the beginning with respect to the after about half an hour is a proof that voltages degrade.
In order to assess the behavior within the package even better, a certain number of measurement points is necessary. Thus, the component including in zones can be divided. This very important zone information provide much more detailed evidence of what at which point the MEMV® process was effected. The older system VSR with the single-point filled not reliable its purpose in many applications. With the expansion towards the MEMV® process with significantly more measurement points, for example, 24 pieces, can now achieve even better process reliability beyond, and the results can be confirmed proven.
Photo 1: Two headstocks are vertically with the multi-function machine WIAP DM3S with the MEMV® (Metal stress relief with vibration) process relaxed (all photos: Hans-Peter Widmer)
In the component size is available for the MEMV® process almost no bounds. Up to 200 tons and be relaxed by using the vibration technology components. During stress these limits are reached more quickly, since only the transport already is a major challenge to the annealing furnace of such a component. Also, the annealing furnace must be of sufficient size itself. Especially in such cases MEMV® is the technology of the future and provides no competitive process is to stress relieving Optionally, a combination of both technologies conceivable. Since low-stress annealed components often have residual stresses, such components can then be edited additionally with the MEMV® process.
Photo 2: The rollers jig provides a robust connection with the component
Inaccuracies due to transportation
Not infrequently, the components are processed at the supplier, consuming provided with a measuring protocol and subsequently transported to the mechanical engineer on a highly accurate machine. When commissioning is this then undesirable changes in the dimensions fixed, for example, caused by transport. Such problems can be overcome - often enough even a 40-minute MEMV® treatment. In such cases also, the process is no competition with stress relief, but rather should be seen as expanding opportunities for their own precise machine tools.
If a component already be pre-painted after fabrication, to delay problems can not be solved with an annealing furnace in most cases. Here, too MEMV® may be the drug of choice - it burns for a no color and the components do not have to be dismantled.
Patented: simultaneously stimulate horizontally and vertically
Below is especially the 2-axis stimulator talk, because this is the most commonly used activator (often called vibrator). The WIAP AG offers a variety of models, such as V5 for components up to 5 tons, V20 (20 tons) or V50 up to 50 tons workpiece weight. Come here now a single-axis measuring probe for use to measure the vibrations of the stimulator should always be mounted in those axial direction in which even with the MEMV® process is relaxed. However, this previous point measurement that can be made with a 3D probe, not nearly as meaningful as a multi-point measurement. Therefore, the new MEMV® technology is preferable in most cases over the older. In series production, a component analysis can be made much more precisely by using the multi-point measurement beyond.
A new VS-vibrator for horizontal and vertical excitation in all three axis directions was filed in 2014 in Switzerland and 2015 in Germany for patent. He is, among other things especially to encourage all axial directions simultaneously during a welding operation. In order to achieve the "vibration welding" can be significantly better results.
Numerous measurement experiments for optimal results
The WIAP AG has conducted hundreds of component surveys in recent years, especially with the insightful multi-point measurements. The detailed analysis of the data information about the component shapes ensures permanent for additional improvements in the use of various MEMV® method. This also applies to customers who are already using the WIAP systems. Again, confirm the safety process and documented accordingly even better data collection.
Photo 3: Vertical WIAP MEMV® Stimulator in 45° arrangement: the component measurement on WIAP DM3S machine bed this provides valuable information about process status
All collected data are extremely important for the Swiss, among other things, simplifying the software at a fully automatic WIAP MEMV® system critical programming. In addition, it provides essential information, the direction in which the exciting means is disposed and which subsequently at which point exactly happens with the component.
Automotive industry relies on vibration technology
The WIAP AG completed surveys for flame-looking components, which were then annealed in the oven. However, many previously flame or hydraulically related components go back in a curved position. the MEMV® method solves this problem along the lines set vibrate + edit = no delay. The problem was so far rather the exact scientific proof, although hundreds of customers can already prove that it works exactly in this form.
Especially in the automotive industry processes dive accordingly time- and cost-intensive to more often. For example, numerous vehicle stand are required in the assembly where welding operations were carried out. Align or even glow comes here hardly considered. Instead, use numerous customers within the automotive industry, the vibration technology.
Improved vibration method and new CNC machine
When metal stress relief with vibration can be expected further development thrusts future. The same procedure for 50 years of 1-direction vibration (VSR) to be improved. Already, WIAP AG has numerous device models that work with the MEMV® process. The measuring methods for the degraded tensions if during annealing or vibration, improve the Swiss permanent. Currently, intensive further research be operated here. In future, the methods will help, among other things, scientifically prove the results of the stress relieving metal with vibration.
The WIAP AG currently designed a CNC MEMV® expansion device with which all axial directions can be excited in a few minutes. Whether horizontal or vertical: the MEMV® system offers all in one device. Numerous findings from the recent past flow into the current products with one, as if only a few G's suggestions are necessary, but all zones are reached.
Photo 4: Fully automatic CNC multi-function machine tool WIAP DM3S to unmanned machining of steel reinforcements (design and manufacture: WIAP AG)
Thanks to the new MEMV® process today can be used numerous ways that facilitate the use of this cost-saving technology crucial. The WIAP AG currently designed a machine as it is seen on the 3D CAD illustration. Without the comfortable MEMV® process of Swiss specialists applying these economic, compared to the stress relieving significantly less energy-intensive technology would be much more complicated than it is today. In total, there are numerous arguments for the use of the extended MEMV® process "Metal stress relief relax with vibration" in the production and manufacturing environment.
Author: Hans-Peter Widmer is authorized signatory of WIAP AG in Dulliken / CH.