R & D

Patented sensor mat prevents postural defects

It records the position of the feet of an employee and detects any shifting of weight. This actively helps to prevent postural defects.


Ergonomics

Scientists from the Fraunhofer Institute for Manufacturing Engineering and Automation IPA have developed a sensor mat for standing workplaces in cooperation with isoloc Schwingungstechnik GmbH.

In the past, sensor mats have been used on areas of the factory floor where humans and robots work closely together. They are placed in the catchment area of the robots and serve to provide occupational safety: as soon as their sensors register an employee, they deactivate the robot and thereby prevent serious occupational accidents. The sensor mats can also have a good effect at standing workplaces without a robot, however. They help to improve ergonomic working and also prevent postural defects and the resulting occupational accidents. After all, standing up for longer periods with the same leg being continually subjected to more strain than the other one or when the weight is unevenly distributed between the feet can result in a malpositioning of the pelvis, stiff and painful muscles not only in the spinal region, but also in the legs, the back of the neck and the shoulder. The consequences can be damage being caused to the intervertebral disks and an increased strain being inflicted on the joints as a result of the motion sequences being changed so that they are unfavourable.

In cooperation with isoloc, a sensor mat for standing workplaces that is equipped with a capacitive sensor system that records the position of the foot of an employee in real-time and thereby detects any shifting of weight was developed by the Fraunhofer IPA Stuttgart Functional Materials department. »This enables the employee to check whether they have adopted a healthy posture and do something about it immediately should this be necessary«, says the Fraunhofer development engineer Stübing.


             

Links to the press releases:
https://www.ipa.fraunhofer.de/de/presse/presseinformationen/sensormatte-beugt-haltungsschaeden-vor.html
https://www.ipa.fraunhofer.de/de/referenzprojekte/steharbeitsplatz_sensormatte_isoloc.html

Technical articles:
https://www.elektrotechnik.vogel.de/sensormatte-am-arbeitsplatz-koennte-haltungsschaeden-vorbeugen-a-961251/
https://www.konstruktionspraxis.vogel.de/sensormatte-am-arbeitsplatz-koennte-haltungsschaeden-vorbeugen-a-961255/

 

 

 

“Elastomer Absorbed Circular Saw Flange“ Research Project in Cooperation with Fraunhofer IPA, 2015-2017(2019) The vibration behaviour of circular saws has a decisive influence on the width of the kerf, the quality of the cut and the noise emission during

The insertion of vibration-absorbing layers in clamping flanges provides considerable potential for the sawing process.

The Fraunhofer IPA and isoloc Schwingungstechnik GmbH therefore examined the possibilities of reducing vibrations by integrating vibration-damping elastomers in the flange clamping area.

 

Summary and Outlook

The insertion of vibration-absorbing layers in clamping flanges provides considerable potential for the sawing process.  It was possible to achieve a 50 percent reduction of the operational vibration at the edge of the sawblade with a tool diameter of 350 mm. This reduction was proven for three rotational speeds. Measurements of the decay behaviour and an observation of the modal degrees of vibration absorption resulted in determination of reduced vibration behaviour throughout.
The new flange system shall now be developed further for use in the woodworking trade. The next step shall be to transfer the principle to a panel-cutting installation with max. tool diameters of 650 mm. This shall enable an estimation to be made of the practicability of the flange solution and the effects on the quality of the of the cut.

Fachartikel

Fig. 1: Comparison of the dying out times of the vibration amplitudes of a circular sawblade with/without isoloc absorption

Fig. 2: Comparison of the vibration amplitudes of various circular sawblades with different diameters and rotational speeds - without isoloc absorption

Abb. 3: : Comparison of the vibration amplitudes of a circular sawblade with a diameter of 500 mm - with isoloc absorptiong

 

 

 

Participation in the Project-Accompany Committee, “Development of Absorbed Tool Holders for Long Overhanging and Rotating Tools (GDW)" | 2017-2018

Research Agency: Institute for Manufacturing Engineering and Machine Tools (IFW), Hanover

Presentation of the problem:
When using milling tools, the tool holder is a substantial influencing factor as regards the process behaviour as it is the interface between the tool and the spindle. It is especially the case with long overhanging tool holders that the dynamic characteristics of the tool holder play a decisive role in connection with the process stability. The use of long overhanging tool holders is necessary in cases where areas that are difficult to reach need to be worked on, deep pockets need to be milled or deep boreholes need to be drilled. The long length of the tool holder-tool system and the high length to diameter ratio can quickly result in process instabilities with which the dynamic characteristics of the tool holder play a decisive role. When milling, it is mainly the case that instability results from flexural vibration but the problem with drilling processes is that of torsional vibration. Inadequately absorbed tool holders reduce the process stability and the surface quality, increase wear, and also generate a stressful noise level. Unstable processes create rejections and they can at the same time cause breakages to the tool holder or the tool respectively. The consequence is a reduction of the process parameters such as the rotational speed and the depth of the cut, which in turn reduces the metal removing rate and therefore, the application rate. Furthermore, the performance capacity of the machine is also not made use of to an adequate extent.

Research objective:

Improving the process stability when cutting using long overhanging and rotating tools by using an innovative absorbed tool holder. The tool holder compensates for the disadvantages that result from the high level of dynamic flexibility.

Participation in the ZIM Project "Aktiwa – Reduction of the Vibration Displacement Amplitudes of Printing Cylinders in Flexographic Printing Presses" | 2013 - 2016

Motivation and Objective


It is often the case with flexographic printing presses that the printed images are smeared or are partially white because the printing cylinder is too large, resulting in inverse vibration displacement amplitudes being produced between the printing cylinder (DW) and the impression roller (GGZ) or the anilox roller (RW) respectively during the printing process.
The main cause of the printing disorders is the roller bounce (a sudden change to the height of the print motif when the printing roller is rolled against the GGZ or the RW respectively).

The objective was to reduce the vibration displacement amplitudes of the printing cylinder from the 1st natural bending mode by using controllable vibration absorbers in the centre of the printing cylinder in order to reduce the amplitudes by at least 10 µm or a maximum of 5 µm for all of the printing motifs so that a visible improvement of the print images can be achieved.


Fig.: isoloc controllable vibration absorber (3x)
Source: isoloc Schwingungstechnik GmbH

Fig.: Measurement at a printing cylinder with/without isoloc vibration absorber
Source: ifw Hanover

Fig.: Results of the measurements taken inside a flexographic printing press with/without isoloc installation elements
Source: ifw Hanover

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