6_G-F101_77751_SP_C_0001_C_NULL_0001_441_U_N_Y_N_N_Y_D.PDF

CAGE 77751 G-F101

Revision C

10 September 2014 ii

TABLE OF REVISIONS

Revision Changes Reason for Change Approved

Original Issue

12/02/1975

N/A New Document H. Kleindienst

Revision A

05/03/2012

1.1, 1.3.1, 3.2, 3.3, 4.2, 5.0, Table 1, Deburring

Do’s & Don’ts

General updates to improve descriptions and explanations throughout document.

Incorporated Amendments 1 and 2 into Revision A.

Clarification on requirements against unauthorized metal removal/trimming processes.

Amendments released after original issue.

K. Grube

Revision B

06/03/2014

1.1 Additional clarification added

in final paragraph:

G-F101 Rev B A-10 SPO

Engineering is the only authorized source that can identify whether a particular process is eligible for qualification and define what qualification requirements must be satisfied.

Clarification only A-10 SPO has the authority to approve particular processes based on qualification data.

K. Grube

09/10/2014

1.1 Added Caution and reworded

2nd Paragraph.

In accordance with Air Force request.

S. Miro

3.1 Materials

item c

Added ordering data.

Clarification of type of belt to be used for sanding.

3.2 item d Deleted the word “and.”

Syntax error iii

Revision Changes Reason for Change Approved

3.4.1 Item a Deleted “or rotary filing.”

Only Aluminum oxide is permitted for sanding.

3.4.1 Item d Un-bold text Bolding is not required.

3.4.2 Steel

Alloys Item d

Added Caution pertaining to etch time and the rinse process note.

Air Force request.

3.4.3

Titanium

Item a

Added caution note about alpha case being detrimental to fatigue performance.

Additional information.

iv

TABLE OF CONTENTS

TABLE OF REVISIONS .......................................................................................................................... ii

LIST OF TABLES .................................................................................................................................. v

1.0 INTRODUCTION

1.1 SCOPE

1.2 DEFINITIONS

1.3 APPLICATION

2.0 APPLICABLE DOCUMENTS

2.1 MILITARY

2.2 A-10 PROGRAM SPECIFICATIONS

3.0 REQUIREMENTS

3.1 MATERIALS

3.2 EQUIPMENT

3.3 GENERAL

3.4 SPECIFIC

3.4.1 ALUMINUM ALLOYS

3.4.2 STEEL ALLOYS

3.4.3 TITANIUM

4.0 QUALITY ASSURANCE PROVISIONS

4.1 INSPECTION

4.2 LIMITS

5.0 SAFETY

v

LIST OF TABLES

Table 1. Materials and Maximum Permitted Speeds For Deburring and Blending of Steel and Titanium Alloys

1.0 INTRODUCTION

1.1 SCOPE

This specification defines the requirements for the edge finishing of holes, machined parts, forged and sheet metal parts. Its primary purpose is to ensure edge finishing results in the required surface finish without detrimental effects of overheating, cracking, re-cast layer or other material and/or microstructual changes that would negatively impact structural integrity. It also addresses specific generic cutting/trimming processes

(commercial and/or military) which have been demonstrated to degrade structural integrity. These processes may not be used in the production/procurement of A-10 parts, unless qualified and approved by the cognizant

Air Force engineering organization.

Caution: In particular, laser, plasma, EDM, torch or other thermal cutting, trimming, or coating removal processes are not currently approved for production/procurement of A-10 parts. Likewise, other non-thermal cutting processes involving high pressure fluids and slurries (i.e., water jet) are also not currently approved for use in production/procurement of A-10 parts. Note: Additionally, coating removal processes such as Plastic

Media Blasting (PMB) are approved for use at A-10 Depots (Hill AFB, SABCA, KAL and AMARG)only.

Only those processes controlled by A-10 approved program specifications and A-10 drawings are permitted to be used in the manufacture and in the maintenance of A-10 parts and assemblies.

For any questions regarding qualification regarding qualification of any of the aforementioned processes that are currently not approved for use in production/procurement of A-10 parts, contact A-10 SPO engineering at

Hill AFB, UT. A-10 SPO Engineering is the only authorized source that can identify whether a particular process is eligible for qualification and define what qualification requirements must be satisfied.

1.2 DEFINITIONS

Burrs Projections of metal beyond the normal directions of surfaces that establish an edge.

Edge The intersection of two planes or surfaces.

Sharp Edge Burr free edge without cracks.

Broken Edge A chamfer or radius of 0.008 to 0.015 inch.

Deburring Removal of burrs by producing a smooth slightly-rounded edge.

1.3 APPLICATION

1.3.1 Unless otherwise specified on part drawings or other within part specific process documents, these requirements apply to all aluminum alloys, carbon, alloy, and corrosion resistant steels, high temperature alloys e.g. nickel, cobalt, and titanium alloys.

Only approved processes listed under applicable documents, as well as those detailed in A-10 drawings, USAF

Technical Orders and other A-10 documents specifically issued by the cognizant Air Force engineering authority, are approved for use in A-10 part production/procurement. Other commercial and/or military processes considered for potential application shall be brought to the attention of the cognizant Air Force engineering authority for qualification and approval before they can be adopted for use.

2.0 APPLICABLE DOCUMENTS

2.1 MILITARY

MIL-STD-867 Temper Etch Inspection

2.2 A-10 PROGRAM SPECIFICATIONS

A-F302 Cold working of Holes

F-F101 Machining of Steel

Z-P801 Storage, Handling, Shipping

Z-R901 Codes and Requirements For General Finishes

Z-R902 Codes and Requirements For Ground Support Equipment Finishing

3.0 REQUIREMENTS

3.1 MATERIALS

a) Abrasive cloth or paper, 80 grit or finer, aluminum oxide or silicone carbide, for hand sanding.

b) Abrasive cloth discs and belts, 80 grit or finer, aluminum oxide or silicone carbide, for machine or power operated equipment.

c) Sanding belt, aluminum oxide abrasive, 320 grit or finer, Gold X P320 weight polyester backing, closed coat, cloth belt. Carborundum Company or equivalent.

d) Abrasive cloth or paper with 36 to 80 grit aluminum oxide or silicone carbide for power or hand operated equipment.

3.2 EQUIPMENT

a) Manually operated cutting tools, such as files and carbide tipped deburring tools.

b) Manual and power stainless steel wire brushes (maximum wire diameter 0.005 inch).

c) Power vibrating sander.

d) Various size rubber supports for sanding discs, drums and belt sanders with rubber drive wheels.

e) Solid carbide and high speed steel rotary files and deburring tools, various sizes and shapes, as required.

f) Various speed electric or air motors for disc and drum types of deburring tools. Peripheral speed restrictions are shown in Table I and specified in paragraphs 3.4.1, 3.4.2 and 3.4.3.

g) Belt sanders, both portable and stationary. Peripheral speed restrictions are shown in Table I and specified in paragraphs 3.4.1, 3. 4. 2 and 3. 4. 3.

h) Stationary table disc and drum sanders. Peripheral speed restrictions are shown in Table I and specified in paragraph 3.4.1, 3.4.2 and 3.4.3.

3.3 GENERAL

a) When drawings specify "break sharp edges" but does not include a specific chamfer or radius, break sharp edges to a chamfer or radius of 0.008 - 0.015. (For holes see 3.3 n.)

b) Parts shall be free of dirt or other contaminants that may be imbedded in the surface during deburring.

Protective greases or oils need not be removed before deburring. Only approved degreasers and other surface cleaners shall be used to minimize accidental detrimental pitting or chemical interactions with the base metal.

c) Care shall be exercised to insure that adjacent flanges and structure are not accidentally undercut while deburring other areas.

d) Abrasive cloths and papers shall not be used after they become loaded with material and cease to cut properly.

e) Prior to forming of sheet and extruded parts of "net" dimensions (i. e. , when edges are not to be subsequently trimmed or machined) the finishing of edges shall meet the requirements of this specification, produce dimensionally acceptable parts ,and not have edge cracking due to the forming operation. The drawing supersedes this specification.

f) Unless otherwise specified on the Engineering drawing, the final edge face roughness shall not exceed that specified for the smoothest adjacent surface or 63RHR, as a maximum.

g) Deburring to this specification shall be done when possible prior to application of Alodining® (chemical film treating), anodizing, plating, or painting. Where holes are cut/drilled/reamed on assembly they shall be finished in accordance with drawing requirements.

h) Materials in 3.1d may be used only for gross metal removal such as sanding skins to profile specified and reducing thickness of machined parts. Use progressively finer grit paper until surfaces meet the desired dimensions with the finish texture required. Incomplete removal of coarser sanding marks will be indicated by widely spaced surface scratches. Such surfaces are not acceptable and must be reworked to remove these scratches. The specified part dimensions must be maintained. NOTE: ABRASIVES COARSER THAN 80-GRIT

SHALL NOT BE USED ON THE FLAT SURFACE OF SHEET METAL PARTS OR FOR HOLE OR EDGE DEBURRING.

i) Clean steel parts immediately after deburring and apply corrosion protective coatings. Coatings per Z-P801 shall be used for protection during in-process operations or storage; coatings per Z-R901 or Z-R902 and drawing callout shall be replaced on steel parts as soon as deburring has been completed.

j) Use extreme care in deburring aluminum alloys to prevent excessive removing of cladding from clad material or excessive material removal from non-clad surfaces.

k) Touch-Up areas per the applicable finish specification where the deburring procedure has removed the protective finish.

l) Dissimilar materials shall not be deburred using the same abrasive sheet, disc, drum or belt. Compliance with this requirement is necessary to prevent contamination of parts and resultant corrosion.

m) Drill points shall not be used to deburr holes. Only tools specifically intended for hole de-burring shall be used (i.e., Cogsdill Tool Products Inc. BURRAWAY, BURROFF, SEDT-SMOOTH EDGE, Umpco Inc. Burr-Qwik, or multi-flute countersinks, etc.).

n) When deburring holes use caution to prevent countersinking and do not exceed prescribed dimension for deburring. Fastener holes in material less than 0.080", but more than 0.050" in depth shall not be radiused or chamfered more than 10% of thickness per side; 0.050" and less, reduce or chamfer not more than 0.005" per side. Holes fabricated in the sequence of operations for automatic riveting need not be deburred. Not

Applicable to Fatigue and Fracture critical holes.

o) Deburring shall result in an edge condition that is free of tears or cracks.

p) Deburring shall not be performed near surfaces to which sealants or adhesives have been applied until fully cured or protected to prevent particle imbedding.

q) Holes to be cold worked shall not be chamfered or radiused prior to cold working but burrs shall be removed, in accordance with sequence instructions of A-F302, Section 3.4.4.

3.4 SPECIFIC

3.4.1 ALUMINUM ALLOYS

a) Peripheral speeds of 5000 S. F. M. * shall not be exceeded during disc and drum sanding. *S. F. M. = Surface feet per minute.

b) Peripheral speeds of 6300 S.F.M. shall not be exceeded sanding with a belt sander and the sanding belt of paragraph 3.1c.

c) Do not use wire brush to deburr or break edge on alcad parts.

d) Silicone carbide shall not be used on aluminum. Use only aluminum oxide.

3.4.2 STEEL ALLOYS

a) Peripheral speeds for various deburring methods shall not exceed the limits shown in Table I. In addition to following the requirements of peripheral speeds aggressive pressure caused by heavy leaning on the tool can cause over heating and therefore not permitted.

b) All steel surfaces deburred or blended by solid carbide rotary files or deburring tools operated at speeds in excess of 1500 S. F. M. shall be abrasively finished to remove tool marks generated by the deburring operation.

c) Holes in steel alloy may be deburred or edges broken with carbide rotary deburring tools; however, peripheral speed shall not exceed 1500 S.F.M. The chamfer or radius produced during hole deburring need not be abrasive finished except as needed to meet the requirements of Paragraph 4.1.

d) All steel parts that are heat treated to ultimate tensile strengths exceeding 180,000 psi shall be temper etched per MIL-STD-867 if, after heat treating, they have been deburred using power equipment. (Ref. F-F101).

Caution: Attention should be given to etch times and subsequent rinse processes.

3.4.3 TITANIUM

a) Peripheral speeds for various deburring methods shall not exceed the limits shown in Table I. Any surface discoloriztion, darkening or discoloring of titanium is not permitted and is an indication of generating too much surface heat/pressure caused by excess pressure from leaning on the tool during deburring and blending operations. Caution: this is indicative of the formation of an Alpha case known to be detrimental to fatigue performance.

b) All titanium surfaces deburred or blended by using high speed steel (H.S.S.) or carbide rotary files or deburring tools operated at speeds in excess of 250 S.F.M. shall be abrasively finished to remove all tool marks generated by the deburring operation.

c) Holes in titanium alloys may be deburred or edges broken with H.S.S. or carbide rotary deburring tools.

However, when power equipment is used, peripheral speeds shall not exceed 250 S.F.M. The chamfer or radius produced during hole deburring need not be abrasively finished except as needed to meet the requirements of paragraph 4.1.

d) Grinding wheels, mounted wheel points, sandpaper backed with metal, or sandpaper backed up by rubber harder than 80 Durometer shall not be used for deburring and blending.

4.0 QUALITY ASSURANCE PROVISIONS

4.1 INSPECTION

Quality Assurance shall verify compliance with all the requirements of this specification and shall inspect to assure that:

a) All burrs shall be removed from parts.

b) Parts shall show no evidence of burning or discoloration resulting from excessive speeds and heat.

c) Parts are free from coarse grit marks or unblended scratch marks terminating in an edge.

d) Surface roughness of edges shall be within the limits specified in 3.3d and 3.3e.

e) The deburring has not reduced the material below drawing dimensions in any location.

f) Areas in which clad has been completely removed do not extend more than 0.030 inches from the trim or hole line.

g) Flanges and radii adjacent to deburred areas have not been undercut.

4.2 LIMITS

a) Holes shall be completely free of burrs.

b) Free edges on sheet metal are acceptable as burr free provided burrs in either plane do not exceed 0.003 inch.

c) Machined parts shall be free of burrs.

5.0 SAFETY

a) It is the joint responsibility of supervisors of all pertinent departments to enforce the safety requirements.

b) Approved personnel protection equipment must be worn such as dust masks, respirators and gloves during deburring operations.

c) Eye protection (safety glasses, goggles or face shield) shall be worn during all deburring operations. .

d) When deburring titanium do not permit solvents, smoking, open flames, welding or arcing devices in the area. Keep an adequate supply of fire extinguisher powder in properly marked closed container.

e) Dust must be removed regularly to prevent accumulation on parts, equipment, floors, tables, and clothing.

Table 1. Materials and Maximum Permitted Speeds For Deburring and Blending of Steel and Titanium Alloys

Materials Deburring and

Blending Operations*

Abrasive Material and Grit Size or Tool

Material 1

Maximum

Permitted

Speeds

Steels, Corrosion and

Heat Resistant Alloys

Heat treated to strength levels of

180 ksi and above

Hand Sanding, No Power A12O3 or SiC, 80 Grit or finer No limit

Split Shaft Sanding A12O3 or SiC, 80 Grit or finer 4000 S.F.M.

Disc and Drum Sanding A12O3 or SiC, 80 Grit or finer1 4000 S.F.M.

Belt Sanding A12O3 or SiC, 80 Grit or finer1 4000 S.F.M.

Flap Wheel Sanding A12O3 or SiC, 80 Grit or finer 4000 S.F.M.

Abrasive Impregmated Nylon Wheel Grinding A12O3 or SiC, 80 Grit or finer 4000 S.F.M.

Wire Brushing Stainless Steel Wire,

0.005 inch Dia. or Less

5000 S.F.M.

Mounted Wheel or Point Grinding A12O3 or SiC, 80 Grit or finer 2000 S.F.M.

Rotary Filing, General Solid Carbide 5000 S.F.M.

Rotary Filing, Hole Chamfering Solid Carbide 1500 S.F.M.

All Titanium Alloys

(Annealed or Aged)

Hand Sanding, No Power A12O3 or SiC, 80 Grit or finer No Limit

Split Shaft Sanding A12O3 or SiC, 80 Grit or finer 4000 S. F .M.

Disc and Drum Sanding A12O3 or SiC, 80 Grit or finer1 4000 S.F.M.

Belt Sanding A12O3 or SiC, 80 Grit or finer1 4000 S. F .M.

Flap Wheel Sanding A12O3 or SiC, 80 Grit or finer 4000 S. F .M.

Abrasive Impregnated Nylon Wheel Grinding A12O3 or SiC, 80 Grit or finer 4000 S.F.M.

Wire Brushing Stainless Steel Wire,

0.006 inch Dia. or Less

5000 S.F.M.

Rotary Filing, General H.S.S. or Solid Carbide 2300 S.F.M.

Rotary Filing, Hole Chamfering H.S.S. or Solid Carbide 250 S.F.M.

1 Abrasives, 36 to 80 Grit, may be used for bulk metal removal operations only as defined in Para. 3.3.g.

S. F .M. = Dia. x RPM x .262

*Caution: In addition to following the requirements of peripheral speeds, aggressive pressure caused by heavy leaning on the tool can cause over heating, as defined by too hot to touch or greater than 130˚F. Aggressive leaning on the tool is not permited.

DEBURRING DO'S & DON'TS

DO'S DON'TS

Clean surfaces of dirt and other potential contaminants before start of deburring operations.

Don't deburr surfaces near uncured sealants or adhesives.

Protect sealant and adhesive areas from contamination with deburring residues.

Don't use drill points to deburr holes.

Use hand powered methods for deburring holes whenever possible.

Don't exceed prescribed machine speeds (See

Spec. G-F101, Table I.) when deburring with power-operated equipment.

Use only equipment and methods for deburring approved by Spec. G-F101.

Don't use abrasives coarser than 80 grit, except for gross metal removal - Never for final finishing.

(See Spec. G-F101, paragraph 3.1. 4.)

Clean surfaces after deburring. Steel parts must be protected in accordance with Spec. Z-P801, Z-R901, or

Z-902, as applicable.

Don't use wire brushes to break edges on clad aluminum alloys.

When breaking edges, work parallel to the long dimension of the edge.

Don't use silicon carbide abrasives on aluminum alloys.

Don't use abrasive belts or wheels that have become loaded with deburring residue.

Don't use the same abrasive belt or wheel for deburring dissimilar metals.

Don't "gouge" or countersink surfaces that are being deburred.

Don’t use processes such as laser or torch cutting that result in heat affected zones or other cutting/trimming process that result in unacceptable edge quality.