1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2016 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/ARP1925B AEROSPACE RECOMMENDED PRACTICE ARP1925 REV. B Issued 1986-10 Revised 200
5、1-03Reaffirmed 2016-03 Automated Brush Deburring RATIONALE ARP1925B has been reaffirmed to comply with the SAE five-year review policy. 1. SCOPE:1.1 This recommended practice establishes a procedure for the application of long string abrasive monofilaments to machined aircraft structures for the pur
6、pose of removing burrs produced during the machining operations. This procedure is typically applicable to aluminum, titanium, and steel, but usage is not limited to such applications.1.2 The process is applicable to the removal of light machining burrs but will not remove burrs that have been extru
7、ded by dull cutting tools.1.3 The process described responds to an automated brush deburring method that lends itself to machine automation and robotic applications and is applicable to a wide range of part geometry variables.1.4 Safety - Hazardous Materials:While the materials, methods, application
8、s, and processes described or referenced in this document may involve the use of hazardous materials, this document does not address the hazards which may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials
9、and to take necessary precautionary measures to ensure the health and safety of all personnel involved.2. APPLICABLE DOCUMENTS:2.1 NFPA Publications:Available from the National Fire Protection Association, Battery March Park, Quincy, MA 02269.Code 65 National Fire Protection AssociationCode 481 Nati
10、onal Fire Protection Association3. TECHNICAL REQUIREMENTS:3.1 Process Description:3.1.1 Deburring of aircraft parts has historically been accomplished primarily by hand methods due to the size, complexity, and part volume variability. This document describes a process which offers a simplified appro
11、ach to the automation of the deburring operation. The process is based on the use of ultra-long string abrasive brushes as the deburring media.3.1.2 It is a departure from current industry practice of using only the brush tips as the primary deburring mechanism. The brush filaments are lengthened an
12、d fabricated into a cylindrical brush. The centrifugal force, imparted by the rotational speed of the brush, results in the deburring and the rounding of the part edges by the surface of the filaments in a draw and file action. The flexible filaments wrap around and deburr the edges of the part, con
13、centrating their force on the edges without adversely affecting other part features.3.2 Selection of Equipment:The selection of equipment to be used in the application of the process is determined primarily by the size and part complexity. Complex irregular shaped parts (e.g., aircraft bulkheads and
14、 landing gear struts) are candidates for robotic application, while long rectilinear and integrally stiffened parts (e.g., spars and wing planks) are candidates for automated machinery.3.3 Brush Material:3.3.1 The filament material used in the construction of a long string brush deburring head consi
15、sts of an extruded nylon monofilament containing abrasive particles of aluminum oxide or silicon carbide dispersed throughout the filament and exposed on the surface.3.3.1.1 New particles are exposed as the filament wears.3.3.2 The filament material is available in many combinations of grit size and
16、 filament diameters. Available grit sizes range from 600 to 46, with the larger grit sizes available in the larger filament diameters. Diameters range from 0.012 to 0.060 inch (0.30 to 1.52 mm).3.3.2.1 Grit size for this process should be no coarser than 120 (125 m). Filaments containing abrasive gr
17、it coarser than 80 (180 m) grit are not as effective in material removal, due to the larger particle size, providing fewer cutting edges on the surface of the filament.3.3.2.2 The filament material is currently available in choices of grit loadings from 20% to 40% abrasive with 60% to 80% nylon.3.3.
18、2.3 The filament is also available in nonround shapes, one being rectangular shaped, 0.045 by 0.090 inch (1.14 by 2.29 mm) with similar grit content as round materials. Grit sizes in rectangular filaments range from 320 to 80 mesh.SAE INTERNATIONAL ARP1925B 2 OF 63.3.3 The filament material is avail
19、able from the brush manufacturers in low, medium, and high density filament concentrations. This is a measure of the amount of filament placed in a given length of brush strip.3.3.4 The brushes are currently available in three basic types:3.3.4.1 Straight and spiral strip brushes, where the strips o
20、f brushes are located along the axis of rotation.3.3.4.2 Parallel order and continuous spiral wrap brushes, where the strips are wrapped in a loose or tight pitch around the axis of rotation.4. RECOMMENDED BRUSH CONSTRUCTION:4.1 The following recommended brush construction is based on the best resul
21、ts obtained in the configurations tested and does not imply that all possible combinations have been reviewed.4.2 Abrasive Media:Silicon carbide provides better deburring effectiveness and longer surface abrasive life than aluminum oxide.4.3 Grit Loading:Optimum loading is 60% nylon carrier to 40% a
22、brasive material. This combination provides better deburring effectiveness than a lower abrasive content.4.4 Brush Pack Density:A medium density brush fill is recommended as an economic optimum. The heavy density brush is more aggressive but not enough to offset the increased material cost.4.5 Brush
23、 Trim Length:The brush trim length is the effective length of the filament from the mandrel diameter and should be not less than 3 inches (76 mm) longer than the highest edge from the base of the part to be deburred.4.6 Type of Brush:The type of brush construction is primarily dictated by the part c
24、onfiguration and the degree of deburring aggressiveness required. The strip type is recommended for deburring the under edge of protruding surfaces where maximum wrap-around is required. The continuous tight spiral wrap is recommended where maximum deburring aggressiveness is required on parts witho
25、ut overhanging edges.SAE INTERNATIONAL ARP1925B 3 OF 65. PROCESS PARAMETERS:5.1 Deburring Angle:The deburring angle is defined as the angle of the edge being deburred to the rotational axis of the brush.5.1.1 The recommended angle is 45 with respect to the edge being deburred. The tests results indi
26、cate that the material removal rate remains relatively constant between 0 and 30, decreases slightly between 30 and 45, and declines rapidly beyond 45.5.2 Brush Speed:Speeds between 400 and 500 rpm provide acceptable material removal rates and edge radiusing between 0.010 to 0.040 inches (0.25 to 1.
27、02 mm). Speeds above 600 rpm are not recommended with the long string process. Speeds above 600 rpm result in very rapid fatigue failure of the brush filaments with little increase in deburring effectiveness. Higher speeds also decrease the brushes conformity to part geometry, as well as leading to
28、overheating of the filaments and a tendency for smearing of the nylon onto the work surface.5.3 Lubrication:The use of water or other liquid coolant media is not recommended with the long string deburring process. Water decreases the deburring effectiveness. The flexibility of the brushes, coupled w
29、ith the low brush speed, does not cause excessive heating of the surface.5.4 Brush Oscillation:Brush oscillation is not recommended in this process. This process is based on a draw and file action of the filaments, requiring the filament to remain in contact with the edge during the process. Oscilla
30、tion tends to pull the filaments away from the edge, decreasing the deburring effectiveness.5.5 Deburring Effectiveness:The deburring effectiveness is directly related to the grit size, brush density, brush rpm, material, and feed rate. 5.5.1 The material removal rate decreases as the abrasive wears
31、 flush with the filament diameter and then remains constant until the filaments wear out. In-process inspection is recommended. Feed rates shall be regulated to maintain acceptable deburring levels.5.5.2 The deburring rate on 7075 aluminum alloy (with the process conditions the same) is approximatel
32、y twice that for titanium or steel.SAE INTERNATIONAL ARP1925B 4 OF 66. QUALITY ASSURANCE PROCEDURES:6.1 Monitoring the Process:This process should be monitored and adjusted as required to maintain an acceptable edge break.7. ENVIRONMENTAL CONSIDERATIONS:7.1 Dust Collection:This process produces a ve
33、ry fine dust. A suitable dust collector should be provided on any equipment designed for this process (See 1.4).7.2 Waste Disposal:The process waste consists of a very fine dust, consisting of the base metal being deburred, along with small amounts of silicon carbide and nylon (or aluminum oxide and
34、 nylon) particles. This material should be disposed of by procedures recommended by the Environmental Protection Agency.7.3 Fire Hazard:The very fine dust produced by this process, as with all current brush and belt deburring equipment, is considered a potential fire hazard, unless the proper handli
35、ng procedures are followed. All procedures and installations pertaining to the operation of long string abrasive brush deburring equipment should adhere to the National Fire Protection Association Code Numbers 65 and 481 for the processing and finishing of aluminum and titanium.8. QUALITY ASSURANCE
36、CONSIDERATIONS:8.1 Edge Quality:This process produces a consistent edge break and radii without chatter marks and nicks prevalent with hand methods.8.2 Surface Finish:This process will improve the surface finish. The coarser the surface finish prior to deburring, the greater will be the percentage o
37、f improvement. This process has very little effect on surface finishes below 30 units (0.8 m).8.3 Metallurgical Considerations:This process produces improved stress-corrosion properties on surfaces that the brush contacts. Test results have shown residual surface and subsurface tensile stresses (on
38、surfaces contacted by the brushes) are converted to compressive stresses.SAE INTERNATIONAL ARP1925B 5 OF 69. NOTES:9.1 A change bar ( l ) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous i
39、ssue of this specification. An (R) symbol to the left of the document title indicates a complete revision of the specification, including technical revisions. Change bars and (R) are not used in original publications, nor in specifications that contain editorial changes only.9.2 Dimensions and properties in inch/pound units are primary; dimensions and properties in SI units are shown as the approximate equivalents of the primary units and are presented only for information.PREPARED UNDER THE JURISDICTION OFAMS COMMITTEE “B”SAE INTERNATIONAL ARP1925B 6 OF 6
