Ensuring safe working conditions during manual abrasive processing of welded joints of frame elements of transport vehicles

Abstract

One of the essential problems of current mechanical engineering is the re-duction of noise and vibration of technological processes. Excessive noise not only leads to the developing of operator illnesses, but is also an indicator of the poor quality of the final product. The article deals with the problem of reducing hazardous and harmful production factors during manual processing of welded joints of vehicle body elements. An obligatory stage after welding is the mechanical abrasive treatment of welded joints to remove stress concentrators and straighten the profile. The existing technology uses a hand-held grinder, which creates a lot of noise and vibration and reduces the accuracy of welding seams. It is shown that with the existing technology, the noise levels are exceeded in the frequency range of 250…8000 Hz and reach 20 dB. To reduce the noise level, theoretical results were obtained for the dependences of the vibrational velocities of the abrasive tool and the results of experimental studies of the noise and vibration spectra during manual abrasive processing of welded seams of body structures. Obtained mathematical models enable the calculation of sound pressure level for abrasive processing. A scheme of a device is proposed that makes it possible to reduce the level of sound pressure during manual abrasive processing of welded seams of frame structures and its advantage over vibration damping coatings is presented. The combination of an integrated approach and protective equipment can decrease the sound pressure level by as much as 30 dB.