1、AGMA 2010-A 94 Obi37575 0003539 07 ANSIIAGMA 2010-A94 AMERICAN NATIONAL STANDARD Measuring Instrument Calibration - Part I, Involute Measurement AGMA STANDARD Copyright American Gear Manufacturers Association Provided by IHS under license with AGMANot for ResaleNo reproduction or networking permitte
2、d without license from IHS-,-,-AGMA 20LO-A 94 Ob87575 0003540 529 Measuring Machine Calibration - Part I, Involute Measurement AGMA 201 GA94 Approval of an American National Standard requires verification by ANSI that the requirements for due process, consensus, and other criteria for approval have
3、been met by the standards developer. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity
4、. Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved the standardsor not, from ma
5、nufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have
6、the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretation of this standard should be addressed to the Amencan Gear Manufacturers Association. CAUTION NOTICE: AGMA standards are subject to c
7、onstant improvement, revision or withdrawal as dictated by experience. Any person who refers to any AGMATechnical Publication should determine that it is the latest information available from the Association on the subject. Tables or other self-supporting sections may be quoted or extracted in their
8、 entirety. Credit line should read: Extracted from AGMA Standard 201 O-A94, Measuring Machine Calibration - Pad 1, Involute Measurement, with the permission of the publisher, American Gear Manufacturers Association, 1500 King Street, Suite 201, Alexandria, Virginia 2231 4.1 Approved March 24, 1994 A
9、merican National Standards Institute, Inc. ABSTRACT: This standard is applicable solely to the qualification of geartooth profile inspection instruments. It provides proceduresfor the design, calibration, and traceability of involute, pin, and plane (flank) masters. It also covers condition evaluati
10、on of involute measuring instruments such as probe location, gain, hysteresis, etc. Recommendations are included for establishment of a proper environment and for statistical data evaluation procedures. Copyright O, 1994 by American Gear Manufacturers Association Published by American Gear Manufactu
11、rers Association 1500 King Street, Suite 201, Alexandria, Virginia 22314 March 24, 1994 ISBN: 1-55589-630-8 ii Copyright American Gear Manufacturers Association Provided by IHS under license with AGMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AGHA 20LO-A 94 W
12、Ob87575 0003543 4b5 AN SUAGMA 201 a geometric condition whereby all surfaces are of equal distance from a given center point. Stability is the total variation in the measurements obtained with a measuring system on the same master when measuring a single characteristic over an extended time period.
13、See figure 4. Figure 4 - Stability Uncertainty. An indication of the variability associ- ated with a measured value that takes into account two major components of error: a) bias, and; b) the random error attributed to the impreci- NOTE: Quantitative measures of uncertainty gener- ally require descr
14、iptive statements of explanation because of differingtraditions of usage and because of differing circumstances. For example: 1) the bias and imprecision may both be negligible; 2) the bias may not be negligible while the imprecision is negligible; 3) neitherthe bias nor the imprecision may be negli
15、gible; 4) the bias may be negligible while the imprecision is not negligible. Variation is the plus or minus change from the nominal value. Variability is the change or inconsistency of variations. X - Flow rate and velocity of the cooling medium; - Frequency and amplitude of temperature variations
16、of the cooling medium; - Temperature gradients within the cooling (heating) medium; - Vibrations; - Electrical power analysis. 4.1.2 Practical guidelines The following guidelines are for measurements to the nearest 0.0002 inch. These are guidelines, and compliance does not guarantee measurements to
17、this level. - Artifact temperature. Tooling and artifacts should be left for an adequate period to stabilize to ambient temperature. - Temperature variation. The mean tempera- ture may not change more than 2” F per hour, with a maximum change of 6” F per day. - Temperature cycles. The temperature ma
18、y cycle + or - 3O F, centered on the mean tempera- 2, Calibration organizations such as the National Institute for Standards and Technology (NIST, formerly the National Bureau of Standards) and Physikalisch - Technische Bundesanstalt (PTB). 3, From MlL-STe45662A. 4, A more thorough discussion of the
19、 effects may be found in such standards as ANSI 889.6.2. Copyright American Gear Manufacturers Association Provided by IHS under license with AGMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AGMA EOLO-A 94 m ANSIIAGMA 2010494 Ob87575 0003548 8LT m ture, every 5
20、minutes or faster. If the tempera- ture cycles approach 15 minutes, serious effects on the measuring system are usually noted. The thermal inertia of most mechanical systems will allow for rapid cyclic temperature undulations within these guidelines for the stated accuracy. Many people will use an a
21、ir conditioner in an attempt to achieve thermal control. The tem- perature sensors in these units may be very slow to respond to temperature changes. If the response is slower than 5 minutes, serious effects on measurement accuracy may be noted. - Temperature gradient. The temperature should be with
22、in 1 o F over the entire area of the instrument surface. The best way to do this is with a high air flow. The air flow must be uniform throughout the room to prevent dead spots and prevent gradients. To accomplish this, diifuse the air coming in to the room and if possible de- sign multiple air retu
23、rns to further diffuse the air uniformly in the room. The goal is to have all air moving uniformly in the room and at the same temperature. The moving air must remove heat from electronic controls, computers, motors, hy- draulics, people, lights, etc. to prevent gradients. - Vibrations. Vibrations c
24、aused by the instru- ment movements should not be allowed to interfere with measurements being taken. Also, vibrations from the surrounding environ- ment should be observed or measured. If they are affecting instrument accuracy, vibration isolation of the instrument or a suitable foundation may be n
25、ecessary. - Electrical power supply. Power fluctuation may cause some electronic instruments and computer numerical control positioning systems to malfunction. 4.1.3 Shop environment Many measuring instruments are placed in the nor- mal shop environment. Be aware that it will be diffi- cult to maint
26、ain an accuracy of 0.0002 inch under these circumstances. The accumulation of dirt or other contaminants on the ways of the instrument can cause inaccuracies as well as premature wear. If an instrument must be used in this kind of environment, care must be taken to avoid certain conditions, such as:
27、 - Local radiant heat sources; e.g., space heat- ers or sunlight through nearby windows that will cause distortion of the instrument. - Roof vents that allow cold air to drop on the inst ru ment. - Cooling systems or open windows that cause a draft to hit one side of the instrument. 4.2 Measurement
28、system condition Several characteristics of the measuring instrument and readout system should be checked or verified before proceeding with artifact measurement. See annex F. 4.2.1 Instrument alignment When the instrument manufacturer provides proce- dural checks forthe verification of alignments,
29、these checks should be made on a regular basis. This may include such things as runout of centers, whether the centers are coaxial, parallelism of center axis to instrument ways, squareness of ways, etc. 4.2.2 Probe The location and shape of the probe: round, sharp, flat, etc. must be known and veri
30、ified. The probe must not be worn out of shape. Either a sharp point or ball will flatten out, and a flat probe may become grooved or rounded. 4.2.3 Readout condition Meter movements and chart recorders should be checked to the manufacturers specifications such as magnification, linearity, hysteresi
31、s, and fre- quency response. 4.2.4. Table load considerations Instruments that are used to check very large gears (above 40 inches) may deflect or change shape under the weight of the part being tested. This will cause errors in measurement. Such instruments should be checked for alignment with a si
32、mulated load on the table. Gears with significant inertial mass may also cause measurement errors 4.2.5 Tooling and gages Any tooling or gages used in the set up or calibration of a measuring instrument shall be calibrated on a regular basis. 4 Copyright American Gear Manufacturers Association Provi
33、ded by IHS under license with AGMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,- AGMA 20LO-A 94 0687575 0003549 756 5 Recommended calibration masters This section describes the master artifacts which are recommended for calibration of involute profile testing ins
34、truments. This standard recommends employment of both involute and non-involute (pin or plane) masters for calibration of involute profile testing instruments. The involute master provides a direct calibration reference for observation of test instrument accuracy performance. Non-involute masters se
35、rve as indirect calibration references which provide increased sensitivity to particular elements of instrument variation. 5.1 Master certification The calibration masters represent the next higher order of uncertainty in the hierarchy of calibration. The uncertainty associated with the certified va
36、lues of these calibration masters shall be in accordance with clause 3.2. 5.2 Involute masters An involute master is a calibration artifact which provides a feature of involute form. The involute feature is certified relative to the theoretical involute associated with a specific base circle. 5.2.1
37、Involute master function The bias and variability of an involute profile testing instrument can be determined by calibration of the instrument with a certified involute master (see figures 6 and 7). Observation of calibration test results will reveal the instruments total confor- mance including all
38、 of its individual sources of variation combined in proportion directly relating to its ability to generate a specified involute reference form. The involute master is therefore considered the most direct and appropriate means of calibration. The involute master is particularly well suited to observ
39、ation of slope or ratio type variations of the instrument, which are revealed by a progressive trend of the test trace away from the nominal reference line as the test proceeds. The involute master also provides an excellent reference for the observation of form or localized variations. Masters manu
40、factured with minimum variations from the true involute are preferred for this. ANWAGMA 2010-A94 Involute masters manufactured with significant variations from the true involute can reveal instru- ment variations of hysteresis, gain, probe location, or condition. It may be appropriate that involute
41、form master artifacts include some amount of variation from a true involute surface for the purpose of testing for the presence of a response from the measuring probe. The established amount and location of this variation must be identified on the master artifact certification statement. 5.2.2 Invol
42、ute master calibration The involute master must be calibrated by direct testing of the involute feature with a testing instrument of appropriate uncertainty. Since a direct testing procedure is employed, uncertainty associated with the procedure affects the involute bias certification on a direct on
43、e to one basis. The involute feature, manufactured with minimum variations from the specified involute, simplifies observation of variations present in the instrument being calibrated. However, since the master is directly calibrated, it may be manufactured with significant variations from the true
44、involute. Such variations must be clearly identified as to amplitude and location in the master certification statement. 5.2.3 Measurement location It may be desirable to limit the testing of the involute master feature to a specified location to minimize the eff ectsof form variation. This may be p
45、articularly desirable on master artifacts manufactured with significant variations from the true involute. 5.3 Non-Involute pin or plane (flank) masters A non-involute master is a calibration artifact which provides a feature of known form other than involute. In practice, the known non-involute for
46、m is tested by an involute profile testing instrument which has been configured to generate a true involute form reference associated with a specified basecircle. The deviation of the given non-involute form from the specified involute form can be calculated thereby defining the correct test result
47、values which should be produced by the instrument. Certification of non-involute masters involves both the metrological analysis of the given master feature geometry and calculation of the features deviation from a specified involute. 5 Copyright American Gear Manufacturers Association Provided by I
48、HS under license with AGMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AGIA 2010-A 74 = Ob87575 0003550 478 ANSVAGMA 201 EI = 7“ Roll angle at start of active profile; 2 = 39O Roll angle at end of active profile; VH= 0.002 Desired amount of profile test trace sl
49、ope modification between start and end of active profile. 8.2.2 Calculations required to determine a modified base circle diameter which would produce the de- sired amount of profile test trace slope modification: Calculate the roll path length, Z, from the start to end of active profile: a) z=- E2 - “Dbn = 1.256637 b) . . .(B. 1) 360 Calculate the base circle diameter modifi- cation, A. move the probe in closer to the centerline if the negative portion of the trace is shorter than
