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Library / WI-305

WI-305 Deburr and Edge Break Standard

WI-305 Deburr and Edge Break Standard

Revision D · Effective 2025-03-10

1 Purpose

This instruction sets the default edge break, the deburr acceptance criteria, and the methods for inspecting edges and internal features on machined parts.

2 Scope

Applies to all machined parts at the Wichita plant, whether deburred at the machine, at the Bay 5 deburr benches, or during rework. Where the drawing, PO or customer specification gives a different requirement, that requirement takes precedence over this instruction.

3 Definitions

  • Burr: any raised, loose or attached material left by machining at an edge or intersection.
  • Edge break: the removal of a sharp edge by a small chamfer or radius.
  • Cross-hole: any hole that intersects another hole or internal bore.
  • Class A surface: a cosmetic or functional surface that the drawing, PO or customer specification designates as Class A. All other surfaces are treated as standard surfaces.

4 Responsibilities

  • Operator / deburr technician: deburrs to this instruction and checks own work before passing parts on.
  • Quality inspector: verifies edge condition at first-piece (WI-120) and final inspection (WI-410).
  • Manufacturing Engineer: identifies cross-holes and Class A surfaces on the setup sheet and specifies tools.

5 Procedure

5.1 Default edge break

  1. When the drawing says "break sharp edges" (or "break all edges") without a value, the edge break is 0.005-0.015 in, as a chamfer or radius.
  2. When the drawing gives a value, use the drawing value. Do not apply the default in addition to a drawing chamfer.
  3. Edges marked "sharp" or "no break" on the drawing are left sharp but must still be free of burrs.
  4. Measure edge break with a calibrated radius gage or the optical comparator. Gages must carry a green calibration label (QP-7.6).

5.2 General deburr requirements

  1. All edges, including thread starts and the first full thread, must be free of burrs that can be seen with the unaided eye or felt with a fingernail drag.
  2. Do not blend, polish or scratch adjacent surfaces while deburring. Tool marks left by deburring that exceed the drawing surface finish are nonconforming.
  3. Use only the hand tools, abrasives and powered tools listed on the setup sheet. Abrasive media must not be used on threads or on Class A surfaces unless the setup sheet allows it.

5.3 Cross-holes and internal features

  1. Every cross-hole and internal intersection identified on the setup sheet must be checked with a borescope after deburring.
  2. Inspect 100% of cross-holes on the first piece and at each in-process check (WI-120). Burrs or loose chips found inside a cross-hole are removed and the hole is re-inspected.
  3. Record borescope checks on the traveler.

5.4 Class A surfaces

  1. Edges bounding a Class A surface must be burr-free when examined at 3x magnification under the bench lamp magnifier.
  2. Handle Class A parts by non-cosmetic surfaces only and set them on clean, padded surfaces. Parts are packaged in individual cavities per WI-520.
  3. Scratches, dings or tool marks on a Class A surface are reported to the inspector; do not attempt to polish them out without Quality approval.

5.5 Safety and cleanliness

  1. Wear ANSI A4 cut-resistant gloves for deburring and for handling sharp parts, per EHS-02.
  2. Do not wear gloves when operating a drill press or any machine with a rotating spindle, including deburring at the machine (EHS-02).
  3. Safety glasses with side shields are required at all deburr benches.
  4. Collect deburr chips and abrasive dust at the bench. Parts going to Bay 6 or Bay 7 (FOD-critical areas) must be blown off and wiped clean before they leave the bench (QP-7.7).

5.6 Nonconforming edges

If an edge break exceeds the maximum allowed, a burr cannot be removed without violating a drawing dimension, or a Class A surface is damaged, stop and red-tag the part per WI-610.

6 Records

Borescope and edge checks are recorded on the traveler, retained 10 years from creation as a quality record (QP-4.2).

7 Revision history

Rev Date Change Approved by
B 2019-07-15 Added default edge break 0.005-0.015 in Ruth Okafor
C 2022-01-10 Added borescope check of cross-holes Ruth Okafor
D 2025-03-10 Added 3x magnification criterion for Class A surfaces; glove rules aligned with EHS-02 Ruth Okafor