The industrial production line is various, the noise decibel and the spectrum distribution in different production lines are the same, but the noise control principle is much the same. First, the stamping production line is used as an example to elaborate the production line noise control mode. The stamping shop is responsible for the parts production task in the industrial production process. With the gradual improvement of the automation of the stamping production line, the production rhythm is increasing gradually, the noise produced in the stamping production is becoming more and more large, the noise of the production line is more than 90dB (A), and the noise value of some production posts is larger than the national standard. Although staff can wear earplugs as personal protective measures, noise has a bad effect on the hearing of some workers in the workshop. Some stamping workshops have also taken measures to increase the damping pad, waste trough and damping coating for the press, but the effect is not obvious. It is necessary to take radical measures to protect the workers from the noise.

(one)selection of noise control schemes  

Noise control can be carried out in the following 3 aspects:            

1, reduce the noise generated by equipment and mold from the source. Production noise mainly comes from mechanical press, mold and parts automatic transmission equipment. In the press workshop, the new press has been taken into consideration. The damping pad is added to the press, the waste tank and the damping coating are added to the press. The noise reduction is only 1-2dB, and the effect is not obvious. It is difficult to change the existing die structure to reduce the noise, and it is easy to affect the quality of the stamping parts. It is difficult to realize the present stage.            

2, the use of management means, through rotation, changing the operation position and other operators to reduce the time of noise impact, but the effect is not obvious.            

3, from the way of noise transmission, we should adopt the way of isolating direct sound or reducing reflection sound. The noise sources in the stamping workshop are concentrated, mainly due to the noise generated by stamping, cutting and scraping of waste materials. The noise coming to the workers is mainly the direct sound from the source to the workers and the reflection from the walls and roofs of the workshop. Considering that the space of the stamping workshop is large, the staff from the sound source is close to the reflection surface, so the direct sound is the main influence to the staff, and the large area sound absorption and noise reduction measures to the workshop wall and the roof are high cost, the technical difficulty is big, and the control scheme of the noise and noise of the stamping production line should be mainly controlled by the direct sound.            

Considering the above 3 aspects, we choose to control the direct sound, and use the sound absorption and sound insulation material to make the sound insulation structure completely closed and de-noising.    

(two) the implementation steps of the noise control scheme

According to the relevant national standard "sanitary limit value of workplace noise (GBZ2 - 2007)", the occupational exposure limit of workplace noise can be referred to the above stated values. The equivalent sound level of the equivalent noise level of the unsteady noise should be calculated according to the equivalent sound level of 8 hours. 5 days a week, the working time is not equal to 8 hours a day, and the equivalent sound level of 8 hours is calculated. The work is not 5 days a week, and the equivalent sound level of 4O hours is calculated.            

According to the hygienic limit of 85dB hours (A) for 8 hours, from the noise reduction effect and economic cost, the implementation steps of noise control in the stamping production line are as follows:

1.Test the noise status in the stamping workshop, and obtain the sound pressure level of the frequency multiplier band of the receiving points, so as to make an economical and reasonable noise control design. During the test, the production equipment works normally. The test points are selected in the operation positions around the production line of the workshop (the working area of the workers observing and managing the production), each 5m point, the position of the test point is 1.5m. The 1/3 frequency doubling spectrum of the sound point is made.            

2.Determine the allowable sound pressure level of the octave bands at the receiving points.

3.The sound pressure level of frequency doubling band is measured from each sound point, and the sound pressure level of each frequency doubling band is allowed according to the noise limit value of 85dB (A), and the amount of sound insulation for each frequency doubling band can be calculated.          

4.considering the effect and cost of noise reduction comprehensively, we choose proper sound insulation structure and components to conduct full closed noise reduction for the production line. 

summarize experience ;

1, before the implementation of noise reduction project, we must make a spectrum analysis of the noise of the production line, so as to make an economical and reasonable noise control design.            

2, all kinds of clearance in noise reduction engineering structure should be sealed as far as possible.            

3, noise reduction engineering structure should balance the process operability and equipment maintainability, minimize the adverse impact on operation and equipment maintenance.