2.3 Tooling and Machine Capability

Scale sanity:Calculation: add aThe 100 mm verification barC; every overlay gets checked with calipers before use.

2.3.4 Pins, pegs & locators (make it hard to be wrong)_pk

• Keyed datum holes (A/B)is socalculated against the overlaytolerance only mounts one way.
• Zero-point connector nests (3D-printed or machined) that set angle/clocking and strain relief before first bend.
• Adjustable loop gauges (sliding stops) with engraved target ± tolerancelimits (e.g., 80+/- ±101.0 mm).
• RoundedMandate: pinsThe machine must achieve a C_pk ≥ 1.33 (no4σ) burrs),to sleevedbe wherequalified. jacketIf rubs;C_pk never< force1.33, sharpthe 90°machine turns.requires calibration, belt tensioning, or mechanical repair.

Statistical Process Control (SPC)

Once qualified, the machine is monitored using SPC control charts (X-Bar and R charts).

• Drift Detection: SPC detects drive roller slippage (wire length drifting shorter) or blade mechanism play (strip length variance) before they create out-of-spec parts.
• ShieldControl bond stations: metal ear + 360° clamp nest right at the chassis entry point.
  




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2.3.5 Layout rules that speed hands (and save jackets)

• First clamp before first bendLimits: (50–80Limits mmare fromset backshell).
• Min radius printed along tight arcs (6×OD static / 10×OD dynamic).
• Stagger splices ≥30 mm; never place splices at bends.
• Straight runs long enough to install boots/heat-shrink without scorching nearby wires (add heat box zones).
• Cable crossing minimized; where needed, cross at 90° and label the layering orderbased on the overlay.machine's proven capability, not the wide engineering tolerance.




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2.3.62 ErgonomicsBlade (taktMaintenance: livesThe here)Conductor's Enemy

• Board

  Stripping height/tiltblades adjustable;are workconsumables. inAs they wear, they lose the elbows-downability zone.

• Left–rightto symmetrycleanly ifsever two techs build together; parts bins on both sides.
• Lighting brightinsulation and diffuse; no glare on clear heat-shrink.
• Tool shadows: crimp tool with die ID, hot-air nozzle, scissors, lacing—each returnsbegin to tear or crush it. More critically, a labeleddull spot.
• Wasteblade chutesrequires formore wireforce, offcuts and sleeve skeletons; keepincreasing the boardrisk clean.
  

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20.3.7 One-off vs volume: how to blend without chaos

Start one-off:

• Pegboard, paper overlay, painter’s tape notes. Logof loop lengths, clamp positions, and gotchas directly on the print.

Freeze to volume:

• Convert notes into a rev-controlled overlay; replace tape with printed callouts.
• Swap movable pegs for keyed fixtures and loop gauges.
• Create a module lane: pigtails, branch whips, shield straps (19.5) prebuilt and tested queue to the board.

Family boards:

• Same datum holes and clamp rail across variants; use option markers (A/B/C) and Do-Not-Stuff labels to keep a single overlay.
  

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2.3.8 Integrated aids (make the board do the thinking)

• Centerline ruler every 100 mm for quick cut checks.
• Photo boxes: “What good looks like” for each branch/boot.
• Sleeve lengths printed near stations (before-shrink size).
• Pin-test docks (pogo or break-out headers) for subassembly continuity before loom-up.
• Heat-proof nests sized to each solder sleeve; stencil “heat here.”
  




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2.3.9 Revision control & storage (no zombie boards)

• Overlay shows Harness PN–Rev, effectivity, change bar; QR to drawing pack.
• Red tag obsolete boards; store vertical in a rack by family; dust covers on high-use fixtures.
• Pre-flight check card on each board: overlay rev, tools present, gauges set—signed at start of shift.




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2.3.10 Capacity planning with boards (simple math)

• Takt target: Available time / Required units.
• Build time per board from last three lots.
• Boards needed = ceil(Build time / Takt).
• If >1, split flow: parallel boardsscraping or module kittingnicking tothe keepconductor plating.

  The Scraping Defect

  A sharp blade cuts insulation cleanly. A dull blade compresses the maininsulation boardagainst busy.the Trackcopper strands before cutting. This friction can scrape the FPYtin or silver plating off the strands, exposing the base copper.

  • Class 3 Impact: Scraped plating reduces corrosion resistance and is a potential cause for rejection in high-reliability aerospace/defense harnesses.

  Preventive Maintenance (PM) Schedule

  Blade maintenance must be minutescycle-based, waitingnot time-based.

  • Cycle Count: PMs should be triggered by the machine's cut counter (e.g., inspect every 100,000 cycles).
  • Visual Inspection: Blades must be removed and inspected under 10x magnification.
    • Accept: Sharp, defined edge; coating intact (if TiN coated).
    • Reject: Chipping, rounded edges, or material buildup.
  • Changeover: Blades are replaced as matched sets. Never replace only one blade in a pair, as this causes misalignment and conductor damage.

  2.3.3 Gripper and Roller Maintenance

  The feed mechanism (rollers/belts) and the immobilization mechanism (grippers) determine length accuracy.

  • Roller Glazing: Urethane feed rollers collect dust and wax from wire insulation, becoming "glazed" (smooth/hard). This causes slippage. Mandate: Daily cleaning with Isopropyl Alcohol (IPA) to restore grip.
  • Gripper Pressure: If grippers are set too tight, they crush the insulation, altering the wire's dielectric properties (critical for modulesCoax). If too loose, the wire slips during stripping, causing a short strip length.
    

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  Final

  2.3.11Checklist: PitfallsTooling →and smallest reliable fixCapability

  PitfallMandate	SymptomCriteria	FirstVerification moveAction
  Machine Qualification	Mis-scaledCut/Strip overlaymachines must demonstrate Cpk ≥ 1.33 on length tolerances.	HarnessInitial short/long	Addcapability 100study mmperformed scaleand bar;logged printfor witheach scalingmachine locked; verify on receiptannually.
  Blade Inspection	SharpBlades pinsinspected /for metalwear/chipping edgesbased on cycle count (not just time).	JacketPM nicks	SleeveLog pins;requires add"Pass/Fail" entry for blade edge guards;condition inspectunder weeklymagnification.
  Conductor Integrity	Zero scrapingLoops “byof feel”conductor plating allowed.	FieldFirst reachArticle issues	InstallInspection go/no-go(FAI) loopincludes gaugesmicroscopic withcheck tolerancesof printedthe conductor surface after stripping.
  Feed Maintenance	Heat-shrinkFeed scorchesrollers/belts neighborscleaned daily to remove glazing.	Browning,Operator brittlechecklist jackets	Addconfirms heatrollers plates;are separateclean heatand stations;provide useconsistent proper nozzlestraction.
  Process Drift	SPC ChartsObsolete boardused into circulationmonitor strip length variation.	VariantOperator mismatches	QRstops +machine revif on7 overlay;consecutive red-tagpoints &trend quarantinein oldone overlays
  Boarddirection becomes(indicating ablade storageloosening table	Slowor builds, lost tools	5S: shadow tools, waste chutes, no bins on the board surfacewear).

  
  

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  2.3.12 Pocket checklists

  Designing a board

  • 1:1 centerline with min radius and direction arrows
  • Connector nests keyed; pin-1 and latch shown
  • Loop gauges with target ± tol; clamp icons placed
  • Label positions, sleeve lengths, shield bond station
  • Overlay rev, PN, QR; 100 mm scale bar

  Before first build

  • Overlay scale verified; pegs/nests fit; heat zones safe
  • Tool shadows stocked; ESD mat where hands live
  • Module lane ready (pigtails, branches pre-tested)

  Daily use

  • Pre-flight card signed; gauges set; correct rev
  • Clean board; bins stocked; waste emptied
  • First article passes loop gauges and continuity

  After run

  • Capture kaizen: one change to overlay/fixtures
  • Store board vertical; cover on; red-tag any damage
    

  
  

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  Standardizing harness boards with revision control and built-in process aids keeps assemblies consistent, fast, and defect-free. When the board itself enforces quality, production speed rises while mistakes and rework disappear.