NAVAIR 17-20MD-14 TECHNICAL MANUAL INSTRUMENT CALIBRATION PROCEDURE MD-14 MD-14 GRANITE SURFACE PLATES THIS PUBLICATION SUPERSEDES NAVAIR 17-20MD-14 DATED 1 FEBRUARY 2003 DISTRIBUTION STATEMENT C. DISTRIBUTION AUTHORIZED TO U.S. GOVERNMENT AGENCIES AND THEIR CONTRACTORS TO PROTECT PUBLICATIONS REQUIRED FOR OFFICIAL USE OR FOR ADMINISTRATIVE OR MD-14 OPERATIONAL PURPOSES ONLY. OTHER REQUESTS FOR THIS DOCUMENT SHALL BE REFERRED TO MEASUREMENT SCIENCE DEPARTMENT, CORONA DIVISION, NAVAL SURFACE WARFARE CENTER, P.O. BOX 5000, CORONA, CA 92878-5000. DESTRUCTION NOTICE - FOR UNCLASSIFIED, LIMITED DOCUMENTS, DESTROY BY ANY METHOD THAT WILL PREVENT DISCLOSURE OF CONTENTS OR “RECONSTRUCTION OF THE DOCUMENT.” PUBLISHED BY DIRECTION OF COMMANDER NAVAL AIR SYSTEMS COMMAND 1 NOVEMBER 2009 NAVAIR 17-20MD-14 LIST OF EFFECTIVE PAGES The purpose of this list is to identify the pages in this document affected by any technical content changes made since the previous release of the document. NOTE: On a revised page, with the exception of the Title, the A, and the i pages, the technical changes are indicated by a vertical line in the outer margin of the page. Page Page Page No. ** Revision* No. ** Revision* No. ** Revision* Title 0 A 0 i 0 1 to 32 0 A-1 0 *Zero in this column indicates an original page. “R” in this column indicates a revised page. **All pages not listed are blank pages. A NAVAIR 17-20MD-14 TABLE OF CONTENTS Section Page 1 Introduction and Description ................................................................................................................... 1 2 Equipment Requirements......................................................................................................................... 1 3 Preliminary Operations............................................................................................................................ 2 4 Calibration Process .................................................................................................................................. 5 4.1 Surface Flatness Tests Using an Autocollimator and Mirrors.............................................................. 5 4.2 Surface Flatness Calculations............................................................................................................... 7 4.3 Surface Deviation Tests Using a Repeat-O-Meter ............................................................................... 12 Navy Calibration Checklist...................................................................................................................... 29 Appendix A: Representative Test Instruments ....................................................................................... A-1 ILLUSTRATIONS Figure Page 1 Initial Surface Flatness Test Configuration, Autocollimator Method...................................................... 3 2 Sequential Positions of the Autocollimator and Corner Mirror ............................................................... 6 3 Sample Measurement Line Tie-In Chart.................................................................................................. 9 4 Sample Measurement Line Variation Chart............................................................................................. 11 TABLES Table Page 1 Calibration Description............................................................................................................................ 1 2 Equipment Requirements......................................................................................................................... 2 i NAVAIR 17-20MD-14 SECTION 1 INTRODUCTION AND DESCRIPTION 1.1 This procedure describes the calibration of Granite Surface Plates. Surface plates that can be calibrated using this procedure include, but are not limited to, the models/sizes listed in Appendix A. The surface plate being calibrated is referred to herein as the TI (Test Instrument). 1.2 All comments concerning this procedure should be directed to the Measurement Science Department, Corona Division, Naval Surface Warfare Center, P.O. Box 5000, Corona, CA 92878-5000. 1.3 This procedure includes tests of essential performance parameters only. Any malfunction noticed during calibration, whether specifically tested for or not, should be corrected. Table 1. Calibration Description TI Performance Test Characteristics Specifications Method Surface flatness Size range: 12 x 12 in. up to Surface deviations are measured 72 x 144 in. with an autocollimator and two mirrors in seconds of arc along Tolerances: the specified datum lines set up Line tie-in: 25 to 100 microinches, on the TI surface. The deviation depending on the grade or 10% of basic values are then converted to tolerance, whichever is greater microinches to determine if the Basic: 50 to 4400 microinches end point values meet the line depending on the size and grade tie-in tolerance and if the station Repeat reading: 25 to 280 microinches, values along each datum line are depending on the size and grade within the basic tolerance. Alternatively, the surface deviations are measured directly with a repeat-o-meter in microinches along the specified datum lines to determine if the values are within the repeat reading tolerance. SECTION 2 EQUIPMENT REQUIREMENTS NOTES Minimum use specifications are the principal parameters required for performance of the calibration, and are included to assist in the selection of alternate equipment, which may be used at the discretion of the using laboratory. Satisfactory performance of alternate items shall be verified prior to use. All applicable equipment must bear evidence of current calibration. The instruments utilized in this procedure were selected from those known to be available at Navy calibration facilities and the listing by make or model number carries no implication of preference, recommendation, or approval for use by other agencies. It is recognized that equivalent equipment produced by other manufacturers may be capable of equally satisfactory performance in this procedure. 1 NAVAIR 17-20MD-14 Table 2. Equipment Requirements Item Minimum Use Calibration Specifications Equipment 2.1 Autocollimator with Minimum range: 2 minutes Davidson Optronics D-638-105 adjustable base Uncertainty: ±0.5 sec of arc Hilger-Watts TA-1 or TA-51 with TA-54 Leitz ABCAA, or AADHM/GAATN with AADFH 2.2 Adjustable corner mirror Flatness: 1/4 fringe Davidson Optronics D-615 2.3 Adjustable movable mirror Flatness: 1/4 fringe Davidson Optronics D-616 2.4 Mirror carriage Pad spacing: 4.0 in. Davidson Optronics D-291 or Uncertainty: NA Metrology Engineering Center D-254-A1 2.5 Mirror carriage Pad spacing: 5.0 in. Davidson Optronics D-292 or Uncertainty: NA Metrology Engineering Center D-254-A2 2.6 Steel straightedge Length: (Minimum) equal to the diagonal length L.S. Starrett 380-36, 380-48, of the TI 380-72 and 380-96 as applicable or equivalent 2.7 Toolmakers steel clamp Capable of clamping the straight edge to the TI Brown & Sharpe 599-754-8; or (2 ea.) Local supply 2.8 Repeat-O-Meter Range: ±0.001 in. Rahn Repeat-O-Meter Uncertainty: ±0.00001 in. SECTION 3 PRELIMINARY OPERATIONS 3.1 Clean the surfaces of the granite surface plate using an approved cleaner; or a mild nonabrasive detergent and water, rinse with clean water and wipe dry with soft paper or cloth towels. 3.2 Ensure that the temperature in the calibration area is within 68° to 76 °F. The humidity should be controlled so as to not exceed 45% RH. 3.3 Ensure that the TI is shielded from sources of radiant heat, and that the ambient temperature is stable to within ±2 °F per hour. 3.4 If the autocollimator (item 2.1) and mirrors (items 2.2, 2.3) are to be used to calibrate the TI, set up the equipment on the TI surface as shown in Figure 1. 2 NAVAIR 17-20MD-14 2.7 CLAMP NORTH 2.6 2.3 STEEL MOVABLE STRAIGHTEDGE MIRROR WEST EAST TI STEEL 2.7 STRAIGHTEDGE CLAMP FACE 2.1 AUTOCOLLIMATOR SOUTH MFG'S NAMEPLATE 2.2 W/SER. NO. CORNER MIRROR Figure 1. Initial Surface Flatness Test Configuration, Autocollimator Method NOTE The test configuration of Figure 1 is required only for an initial acceptance test and calibration, or if test results using the Repeat-O-Meter are suspect. In all other situations, skip to step 3.7 for the preparations involving the Repeat-O-Meter method. 3.5 If the autocollimator method is selected, prepare for the TI calibration as follows: 3.5.1 Referring to Figure 1, lay out and mark eight datum lines for the measurements to follow. The eight datum lines are the four perimeter lines East, West, North and South, the two diagonal lines NW-SE and NE-SW and the two center lines N-S and E-W. NOTES The perimeter lines must lie within 2 inches of the applicable edge for TIs 24 x 24 in. up to 36 x 48 in. in size, or within 4 inches for TIs larger than 36 x 48 in. The stations, or points at which measurements are taken, are marked in increments equal to the pad spacing of the mirror carriage. 3 NAVAIR 17-20MD-14 NOTE When stepping off the profile lines, rigid triangulation shall be adhered to and the intersection points of all lines shall fall within 0.3 inch diameter circle. Adjustable pad spacing sleds may be required for the diagonal profile runs if fixed pad spacing sleds do not meet the requirements. The minimum number of steps per profile lines shall be 6; the maximum step spacing shall be 12 inches. The contract probe or the two pads on the sled which trace the profile line shall be 0.375 inch diameter with a sharp (not beveled) edge. The outrigger pad may be 0.375 inch diameter