1.4 Work Instructions & Visual Aids

Effective Work instructionsInstructions (WIs) are the backbone of repeatablea assembly,high-quality transformingBox complexBuild buildsoperation, standardizing manual tasks and controlling human variation. Because Box Build relies heavily on manual labor (screwing, routing, connecting), the WI must function as the assembly line's primary process control document. A strong WI eliminates guesswork, prevents mistakes, and is essential for achieving the required C_pk (Process Capability Index) in manual assembly steps.

1.4.1 The Work Instruction Mandate

The WI is the legal and technical authority for the assembly sequence. It must be clear, unambiguous, and focused on defect prevention.

A) Structure and Sequencing

The WI must break the entire assembly down into clear,discrete, step-by-sequential steps, ensuring the correct dependencies are met.

• Logical Flow: The instruction must be structured to prevent pre-assembly failure. For instance, a chassis bracket must be mounted before the power supply (PSU) is installed, as mounting screws may become inaccessible afterward.
• Pass/Fail Checkpoints: Each critical step actions.must Wheninclude paireda withmandatory strongsign-off visuals—photos,checkpoint diagrams,(physical routingor maps—theydigital) removewhere guessworkthe operator confirms compliance (e.g., "Confirm TPA is seated").
• Materials and ensureTools: everyThe operator,required regardlesstool (e.g., torque driver) and the exact Part Number (PN) of experience,the performscomponent tasksand fastener must be specified for each step. This links the same way. By linkingBOM directly to MESthe assembly action, preventing the use of incorrect materials.

B) Defect Prevention Focus

Effective WIs prioritize clarity on potential failure modes and filteringerror-proofing, bynot variant,just instructionsassembly staysteps.

current,

• Go/No-Go precise, and aligned to design changes.Conditions: The resultinstruction ismust smootherclearly training,show fewerthe errors,difference between an acceptable output and a productiondefect. lineFor example, for harness routing, the instruction must include a visual limit on the maximum allowable bend radius.
• Cautionary Steps: Warnings must be included for high-risk actions, such as handling ESD-sensitive components, routing near sharp sheet metal edges, or applying pressure near fragile display screens.

1.4.2 Visual Aids and Error Proofing

Visual aids are mandatory in Box Build because complex three-dimensional assembly is difficult to convey with text alone. Visual instruction speeds up training and reduces cognitive load, minimizing human error.

A) Photographic and Exploded Views

• High-Quality Imagery: Use clear, high-resolution photographs taken under optimal lighting. Low-quality images are ambiguous and can cause errors.
• Exploded Views: Use simplified, three-dimensional diagrams (exploded views) to clearly show how components align and fit together, especially for complex mechanical assemblies involving multiple brackets and fasteners.
• Color Coding: Use color overlays or arrows to highlight the specific mounting holes, fastener types, or orientation marks for the current step.

B) Error Proofing (Poka-Yoke)

Work Instructions should support physical error-proofing devices installed at the workstation.

• Confirmation Lighting: Use light curtains or visual indicators that runs with confidence instead of hesitation.

  1.4.1 Purpose (why this matters)

  A good SWI (standard work instruction) makesilluminate the nextcorrect move obvious, evenlocation for a newpart hireor a fastener in the current step.

• Component Presentation: Use shadow boards for hand tools and numbered bins for hardware to ensure the operator selects the correct part for the sequence.
• Tool Interlocks: For critical torque sequences, use sequenced torque drivers that are programmed to lock out if the operator attempts to drive the screws in the wrong order or with the wrong torque setting.

1.4.3 Auditability and Traceability

The Work Instruction serves as the master document linking the assembly process to the final product's quality record.

A) Revision Control

• Mandate: The WI must feature clear revision control (Revision A, B, C, etc.). The shop floor must only use the current, approved revision. Outdated instructions are a major source of assembly failures.
• Control: WIs should be managed electronically and displayed on Mondaytablets ator 6monitors. AM.This Itensures removesthat guessing,when blocksa commonrevision mistakes,is andreleased, linesthe upold version is immediately unavailable to the assembly technician.

B) Final Sign-Off

• Operator Signature: The WI must include space for the assembly technician to sign off on critical steps, providing accountability for proper completion.
• Inspection Sign-Off: The final step must include a sign-off section for the Quality Assurance (QA) inspector to verify compliance with MESthe soentire process before the rightunit variant, torque, label, and test show up at the right minute.

  Rule: one truth, one click, one page per operation.

  
  

  ---

  1.4.2 Anatomy of a great SWI (whatmoves to include)final functional testing.

Final Checklist

SectionMandate	What it showsCriteria	Must-haveVerification detailsAction
HeaderVisual Clarity	OperationWork ID,Instructions PN–Rev,use Varianthigh-resolution images and color overlays to highlight key locations.	TaktAudit target,check safety/PPEconfirms icons,images requiredare ESDunambiguous stateand clearly show component orientation.
PrereqsRevision Control	WhatShop mustfloor beonly readyuses the current, approved revision of the WI.	KitElectronic check,display tools/dies,ensures torqueno driveroutdated IDs,paper consumablescopies lotsare present at the workstation.
Tool/partsTorque boxSpecification	WhatRequired you’llfastener touchtype and torque value are specified for all critical steps.	Photo/outlineWorkstation ofis parts,equipped with the correct, fastener IDs bycalibrated torque grouptool, adhesives/TIM kit.
StepsMaterial (1 page)Linkage	Part Number (PN)Do thisof →components checkand →fasteners nextlisted within the instruction step.	Numbered steps with photos/diagrams, pin-1/latch arrows, “Do/Don’t” inPrevents the marginuse of incorrect hardware or unapproved components.
QualityLogical checksSequence	WhatInstruction “good”flow looksprevents likepre-assembly failure (e.g., inaccessible screws).	Go/no-goNew gauges,Product torqueIntroduction values,(NPI) labelaudit positionconfirms ±the mm,assembly gasketsequence compressionis cuesefficient and feasible.
Variant flagsSign-Off	A/B/COperator differencessigns off on completion of all critical, high-risk assembly steps.	ColoredTraceability badges on steps; hide/show by MES selection
Exit criteria	Done = allowed to proceed	Green boxes: “Torque recorded,” “TPA engaged,” “Label scanned,” “Test result attached”

Keep each operation on one screenrecord (scroll minimal). Long tasks → split into sub-ops.

---

1.4.3 Photos & diagrams (makelinks the imageoperator do the talking)

• Lighting & background: diffuse light; matte background; avoid black-on-black (use colored mats).
• Angles that teach: show the hand position, not just the part; shoot square to surfaces to avoid illusions.
• Callouts: arrows for pin-1, gaskets path, bead direction, airflow. Add a scale (small ruler) when size matters.
• Before/After tiles: left = wrong, right = right (e.g., shield pigtail >10 mm vs ≤10 mm).
• Exploded diagrams: simple line art for stack order; each fastener labeled by PN + torque.
• File discipline: name assets by OpID_Step_Variant; keep an image vault tiedID to the drawingcompletion rev.

---

1.4.4 Exploded views & routing maps (fit, order, path)

• Exploded views: show sequence (1→2→3), standoff heights, washers/spacers, threadlocker color, and torque values grouped by icon/color.
• Routing maps: centerline path, clamp icons, first-bend position, min radius, shield bond points, and label locations with ±5 mm.
• Call gaskets clearly: start/stop marks, corners, compression checks; note scrape points for paint where EMC bonds.
  

---

1.4.5 Variants without confusion

• SWIs filter by scan (SKU/Variant). Onlyof the relevantassembly steps appear.
• Badges (A/B/C) on any shared page; color-coded consistently plant-wide.
• If steps diverge >30%, separate pages—don’t bury “if A then…” in paragraphs.
• Label maps and accessory lists follow SKU; block start if the kit doesn’t match.

---

1.4.6 Digital delivery (station UX that helps, not nags)

• MES tile: zoomable images, 10–30 s video clips for tricky motions, and a checklist with green ticks.
• Hotkeys/foot pedal to advance when hands are full.
• QR on fixtures opens the exact op; no USB sticks.
• Localization: language toggle; minimal text + icons; metric units.
• Offline fallback: cached SWIs print with rev & QR—and auto-expire when a new rev arrives.

---

1.4.7 Torque, adhesives & TIMs (show the amount, not just the idea)

• Torque map snippet on the step; bits by ID; add a witness mark example.
• Threadlocker: dot size photo; color vs chemistry; cure notes.
• TIMs: bead diameter gauge image, pattern (X/lines), “too much/too little” examples; pad locations ghosted on the chassis.

---

1.4.8 Labels & regulatory marks (straight, legal, repeatable)

• Label map: ghosted outlines, datum edge, alignment ± mm and angle.
• Surface prep icon (wipe/apply); squeegee strokes; bubble-free example.
• Dynamic fields (SN, MAC, keys) come from MES; SWI shows where, not what to type.
• Regional marks (CE, UKCA, etc.)—variant-filtered so the wrong region can’t appear.

---

1.4.9 Accessibility & readability

• Font ≥ 10 pt at arm’s length; color contrast high.
• Replace jargon with icons (pin-1 triangle, gasket path, airflow arrow, shield clamp).
• Safety: glove/ESD/eye icons where needed; no wall of text.
  

---

1.4.10 Change control & feedback

• SWIs change only via ECN. Change bars highlight what moved.
• Redline tool at the station: operators can suggest with a photo; PE reviews within 24 h.
• Quarterly refresh of critical photos (new fixtures, new parts finish).
• Training mode: same SWI with extra “why” panels for onboarding.
  

---

1.4.11 Common traps → smallest reliable fix

Trap	Symptom	Fix
Tiny text, busy pages	Questions, slow builds	One page per op, 10 pt font, more pictures
Photos with glare or black-on-black	Missed features	Diffuse light, colored mat, edge highlights
Unlabeled fasteners	Wrong screw/torque	Fastener photos with PN + N·m; color torque groups
Perspective lies	Crooked labels, misaligned parts	Add datum lines and rulers; square camera
Variant in paragraphs	A builds like B	Variant badges and MES filtering
SWI ≠ BOM	Missing parts	SWI pulls MBOM line numbers; sync via MES
Stale printouts	Hidden rev drift	QR + rev watermark; prints auto-expiresequence.

---

1.4.12 Pocket checklists

Authoring

• Header complete (PN–Rev, Variant, takt, PPE)
• Tool/parts box with PNs and torque bits
• Steps: numbered, clear photos/diagrams, pin-1/latch shown
• Quality: gauges, ± mm label positions, torque & checks
• Variant badges and MES filters set; video for tricky moves

Peer review (10 minutes)

• Build the step from the SWI only; time it
• Find one potential error—fix the image, not the paragraph
• Verify MBOM line links; torque/specs match map

At the station

• Scan → correct Variant SWI opens
• Images readable at arm’s length; zoom works
• Exit checks tick green before next op
  

---

Conclusion: Embedding torque specs, label maps, and visual cues into variant-aware digital SWIs creates a single source of truth at the line. This discipline turns instructions into a quiet stabilizer that drives quality, safety, and consistency in every unit built.