1、UDC 534.61 : 621.9.06 : 534.835.46 DEUTSCHE NORMEN June 1978 Measurement of Airborne Noise Emitted by Machines Enveloping Surface Method Machine Tools - DIN 45735 Part 16 Geruschmessung an Maschinen; Luftschallmessung, Hllflchen-Verfahren; Werkzeugmaschinen The principles governing the measurement o
2、f airborn noise emitted by machine tools are set out in DIN 45 635 Part 1 “Measurement of airborne noise emitted by machines; enveloping surface method; general method of measurement“. This subsequent Part contains additional stipulations to those laid down in DIN 45 635 Part I, which have to be com
3、- plied with in the measurement of airborne noise emitted by machine tools. Since there is considerable variation in the operating parameters between one machine tool and another, the operating state at the time of the noise measurement must be clearly defined by the provision of machine and operati
4、ng characteristic values. The particular operating con- ditions are given for different types of machines in further subsequent Parts: DIN 45 635 Part 1601, Part 1602, Part 1603 for individual types of machine tools in the metal processing industry. DIN 45 635 Part 1650, Part 1651, Part 1652 for ind
5、ividual wood processing machines. Further subsequent Parts are in course of preparation. Contents Page Page 1 Purpose and field of application 1 2 Other relevant Standards . 1 3 Terms and parameters . 1 4 Measuring instruments. 1 5 Measurement conditions . 2 5.1 Object of measurement . 2 5.2 Operati
6、ng state of the machine 2 5.3 Installation of the machine 2 5.4 Measuring surface, position and number of 6.1 Messurement of the A sound pressure level 5 6.2 Measurement of the sound pressure spectrum . . 5 6.3 Measurement of the extraneous noise level 5 6.4 Determination of the measuring surface co
7、n- tent S and the measuring surface dimension L, . 5 7 Evaluation 5 8 Uncertainty in measurement. 5 8.1 Uncertainty in the sound measurement 5 8.2 Uncertainty in the determination of the operat- measuringpoints . 2 ing state . 5 -. 5.4.1 Measuring surface . 2 9 Measurement report 5 5.4.2 Measuring d
8、istance 2 5.4.3 Position and number of measuring points 2 10 Instructions for the use of the measurement 5.4.4 Measuring point on a fixed workplace 3 results 6 5.5 Measuring room 3 10.1 Noise characteristic values 6 6 Procedure of the measurement . 5 10.2 Allocation of the noise characteristic value
9、s 6 1 Purpose and field of application 2 Other relevant Standards This Standard, in conjunction with DIN 45 635 Part 1, January 1972 edition, lays down a uniform method for measurement of the noise radiated by machine tools directly to the ambient air (noise emission), so as to ensure comparable mea
10、surement results. The Standard contains stipulations for the procedure of airborne noise measurements in the vicinity of machine tools under fixed operating conditions. This Standard applies to machine tools. A machine tool is defined as a power-operated, permanently fixed ma- chine for the shaping
11、of predominantly metal or wood parts by means of physical, chemical or other methods. This shaping process may or may not involve cutting, possibly with the addition of further materials or pro- ducts. The operating conditions during noise measure- ment are defined separately according to machine ca
12、te- gories in further subsequent Parts. A list of machine categories in relation to metal process- ing machine tools will be found in DIN 69 651 (Prelimin- ary Standard). A list of machine categories in relation to wood processing machines will be found in DIN 8800. DI N 8800 DIN 45 635 Part 1 Wood
13、processing machines; techni- cal classification Measurement of airborne noise emitted by machines; enveloping surface method; general method of measurement Tests of building acoustics; deter- mination of the acoustic absorption in the reverberation chamber classification of metal processing machine
14、tools, numerical scheme, characteristic code for machine families 3 Terms and parameters See DIN 45 635 Part 1 DIN 52 212 DIN 69 651 (Preliminary Standard) Machine tools; 4 Measuring instruments See DIN 45 635 Part 1 Continued on pages 2 to 6 DIN 45 635 Teil 16 engl. Preisgr. 5 Sole sale rights of G
15、erman Standards (DIN-Normen) are with Beuth Verlag GmbH. Berlin 30 and Kln 1 09.82 Vertr.-Nr. O1 05 Page 2 DIN 45 635 Part 16 5 Measurement conditions 5.1 Object of measurement It is necessary to lay down in accurate terms what equipment belongs to the machine on which measure ments are to be carrie
16、d out. All assemblies, which are used solely for the discharge of the functions of the machine, are to be included in general in the machine tool which is the object of the measurement. Sound measurements may be carried out both on individual machine tools and on manufacturing plant; a check is to b
17、e made in each individual case of which parts of a manufacturing plant are to be examined separately. The measurement report must contain exact information on the object of measurement. If parts of a manufacturing plant are not themselves machine tools (e. g. furnaces), the corresponding subsequent
18、Parts of DIN 45 635 are to be used for sound measurements on these units. 5.2 Operating state of the machine Since the noise generated by machine tools is generally governed by their particular operating state, it is neces- sary to lay down appropriate operating conditions, in order to obtain compar
19、able results from the noise measurements. The operating conditions to be laid down will depend on the nature of the machine tool under examination. A distinction is made in principle between two processes: Where the machine tool has its own c o n s t a n t operating state with a uniform noise emissi
20、on, the sound measurement will be based on this state and described by means of the corresponding machine and operating characteristic values (operating state is known and constant). In the case of v a r i a b I e operation, either one or more typical operating states or a characteristic working cyc
21、le, covering in particular the duration of processing of a workpiece, will be defined (fixed setting conditions, test workpieces, test machine tools) and given in the measurement report (operat- ing state is adjusted to given values: general case), or the machine and operating characteristic values
22、(rpm, power, forming forces) are determined during the sound measurement and given in the measurement report (operating state is determined: exceptional case). This form of characterization is of practical advan- tage, if it is desired to convert the value of the noise, emitted by a machine in parti
23、cular operating states, to the value for different operating states (e. g. under full load). If the no-load noise of a machine exceeds the noise dur- ing processing and is given as the only value, this should be pointed out in the measurement report. In the case of machines in which the processing n
24、oise predominates, but cannot be clearly determined, so that only the no-load noise can be measured, it is to be ex- pressly pointed out in the measurement report that the processing noise predominates. When giving the operating characteristic values, obtained during the noise measurement, it is imp
25、ortant to take into account the extent to which deviations from these characteristic values are liable to give rise to uncertain- ties in the noise measurements. Data on the selection of operating conditions in the case of noise measurements on particular machine categories will be found in the subs
26、equent Parts. Noise measurements on machines, on which different types of processing are carried out (combination ma- chines, e. g. for milling and sawing), are to be carried out separately for each type of processing in accordance with the subsequent Parts. 5.3 Installation of the machine The machi
27、ne should be installed so as to correspond to practical operating conditions. If the operational installa- tion is not known or there are more than one possible alternative, the installation selected for the noise measure ment is to be given in the measurement report. The installation conditions for
28、 noise measurements on particular machine categories will be found in the sub- sequent Parts. 5.4 Measuring surface, position and number of measuring points 5.4.1 Measuring surface A reference surface in the simple shape of a parallele- piped block is laid out above the machine as a hypo- thetical d
29、emarcation line round the machine, individual projecting parts, which do not contribute in principle to the sound emission, being disregarded. The measur- ing surface follows this enveloping reference parallele- piped at a measuring distance d, ending at the sound- reflecting, limiting surfaces (see
30、 Fig. 1 and Fig. 2) of the place of installation (e. g. on the floor or along the walls) or is enclosed therein. 5.4.2 Measuring distance The measuring distanced is in general 1 m; values of less than 1 m may be selected, if the sound pressure level of the measuring surface cannot be reliably determ
31、ined, since the extraneous noise (see DIN 45 635 Part 1, Section 3.5) and/or the room factor (see DIN 45 635 Part 1, Section 5.5) is too high. Measurements carried out at very short distances (at least 0.25 m) still permit the possibility of comparison between machines of the same category and of si
32、milar dimensions. Any deviation from the measuring distance of 1 m is to be given in the measurement report. 5.4.3 Position and number of measuring points a) Full-scale arrangement of measuring points The measuring points are shown in Fig. 1 or Fig. 2 as a function of the dimensions of the reference
33、 parallelepiped block for machines installed on the floor. The number of measuring points should be increased, if the horizontal distance between neigh- bouring points exceeds 2 rn or if the difference in dB between the largest and smallest measured value of the A sound pressure level is greater tha
34、n the number of measuring points. Care should be taken to ensure a uniform distribution. In the vicinity of air vent openings, the measuring point should be positioned in such a way that the microphone is not exposed to the air flow. DIN 45 635 Part 16 Page 3 Reference parallelepiped block envelopin
35、g the machine Measuring surface u ic o Additional measuring points if 1, and/or 12 aregreater than 1 m Figure 1. Measuring surface, position and number of measuring points for a height of the reference parallelepiped block ln 2m - Reference parallelepiped block enveloping the machine /Measuring surf
36、ace 9 I : I 9/ 1 /+;-i- I A- ?- - - / / Basic arrangement of the measuring points o Additional measuring points if 1, and/or 12 are greater than 1 m Figure 2. Measuring surface, position and number of measuring points for a height of the reference parallelepiped block 13 2m b) Simplified arrangement
37、 of the measuring points The basic arrangement of the measuring points, shown in Figs. 1 and 2, or an even further simplified arrange- ment can be regarded as adequate for fairly large ma- chines (I, l m; l, l m; l, 2 m), if it can be clearly shown by means of test measurements that the acoustic fie
38、ld of the machine category in question is sufficiently uniform for the measurements to pro- duce identical or higher values of the sound level than the full-scale arrangement of measuring points. 5.4.4 Measuring point on a fixed workplace If there is a fixed workplace in the area of the machine, an
39、additional measuring point is to be provided in the vicinity of the operatives ear (at a lateral distance of 10 cm from the auditory inlet of the right ear) and the measurement results, corrected for the extraneous noise (see DIN 45 635 Part 1, Section 7.1.2) and for the room factor (see Section 5.5
40、1, are to be given separately in the measurement report. The values measured at this point are not taken into account when calculating the measur- ing surface sound pressure level (see DIN 45 635 Partl, Section 7). unless the particular point coincides with a measuring point in accordance with Secti
41、on 5.4.3. The values measured in this way at fixed workplaces are not to be regarded as assessment levels as defined in DIN 45 645 Part 1 “Uniform determination of the assess- ment level for noise immissions“or of VDI 2058 Part 2 “Assessment of industrial noise on the workplace in con- nection with
42、auditory damage“. 5.5 Measuring room See DIN 45 635 Part 1. Page 4 DIN 45 635 Part 16 As an alternative to the procedure laid down in DIN 45 635 Part 1, K, may also be determined in the following way: 5.5.1 Procedure for the determination of the room correction factor K2 by determination of the equi
43、valent sound absorption surface The repercussions of the room, in which the machine is installed, on the spatial mean value of the sound pressure level in accordance with Section 7 depend on occasion on the ratio of the measuring surface S to the equivalent absorption surface A of the room in which
44、the machine is installed. The influence of undesired sound reflections from the ceiling, floor and walls of the room and/or from objects in the vicinity of the machine under examination is taken into account by means of the room correction factor K2. The value of the room correction factor K, depend
45、s in principle on the ratio of the equivalent sound absorp- tion surface A of the room to the measuring surface con- tent S and only to a slight extent on the place of instal- lation of the sound source in the room. K2 has been plotted in Fig. 3 as a function of A/S. It is an essential condition for
46、 the determination of the room correction factor K2 in accordance with Fig. 3 that the measurement should be recorded in a room the dimensions of which (length, width and height) do not differ significantly from each other (i. e. a maximum ratio of 1 : 3). In low or narrow rooms, the room cor- recti
47、on factor K, should be determined by the reference sound source method (see Section 5.5.2). The equivalent sound absorption surface A can be deter- mined from the reverberation time T of the room, in which a broad-band noise has been generated. The re verberation time is the period taken for the sou
48、nd pres- sure level to fall by 60 dB after disconnection of the sound source (see also DIN 52 212). The equivalent sound absorption surface A in m2 is calculated as fol lows: V A = 0.163 - T Where: V Volume of the room in m3 T Reverberation time of the room in s 5.5.2 Procedure for determination of
49、the room correction factor K, by means of a reference sound source The room correction factor K, can also be determined by means of a reference sound source of known sound power. The reference sound source should emit a broad- band noise, similar to the machine noise. The require- ments for a reference sound source are contained in DIN 45 635 Part 1, Annex 3, and DIN 45 635 Part 2, Annex A. The location of the reference sound source is to be selected in such a way that its sound field is spatially similar to that of the machine under examination. Where possible, it should be inst
