✅ 12.1 Planning and BOM Review

Objective: Ensure complete clarity of materials, processes, and design intent before starting the build.

Actions:

• Review the Bill of Materials (BOM) including PCBs, enclosures, cables, connectors, fasteners, labels, etc.

• Cross-check assembly drawings, 3D models, and circuit diagrams.

• Plan tools, fixtures, ESD-safe areas, and required labor skills.

Deliverables:
✔️ Approved BOM
✔️ Work Instructions
✔️ Production Plan

🔧 2. Sub-Assembly Preparation

Objective: Prepare all modules or parts before final assembly.

Sub-assemblies include:

• PCBA (already tested and programmed)

• Cable and wire harnesses

• Fan modules, power supplies

• Switches, displays, and external connectors

Processes:

• Visual inspection of PCBA

• Pre-routing cables

• Crimping, stripping, tinning wires

🏗️ 3. Mechanical Assembly (Enclosure Setup)

Objective: Install mechanical parts and prepare the enclosure.

Steps:

• Assemble base chassis, mounting brackets, heat sinks

• Install standoffs, shielding, or grounding mechanisms

• Use anti-vibration pads or gaskets if required

• Apply thermal pads or paste where needed (e.g., under power components)

🧩 4. PCBA Mounting into Enclosure

Objective: Secure the tested PCB into the product housing.

Steps:

• Align PCBA with mounting holes and I/O cutouts

• Screw or clip the board in place using torque-controlled tools

• Use spacers or insulating pads if specified

• Maintain ESD safety throughout

🔌 5. Cable & Connector Assembly

Objective: Connect all internal interfaces between PCBA and subsystems.

Steps:

• Connect:

  • Power cables

  • Signal cables (USB, HDMI, SATA, etc.)

  • Sensor wiring

• Use zip ties, cable clamps, routing channels to organize

• Ensure strain relief and insulation

• Label cables per wire harness chart if applicable

💽 6. Firmware Installation / Software Loading

Objective: Load firmware or operating system into onboard memory/storage.

Methods:

• Use USB, JTAG, or programming interface

• Apply product-specific config files

• Use batch loading tools for efficiency

• Validate software checksum/version

⚙️ 7. Functional Testing / System Testing

Objective: Verify the full operation of the integrated product.

Tests Include:

• Power-on self-test (POST)

• Input/output port check

• Display or LED behavior

• Connectivity tests (Wi-Fi, Bluetooth, Ethernet)

• Touchscreen or button response

• Audio/video testing

• Software or UI boot-up

Tools:

• Test jigs, diagnostic software, oscilloscopes, network analyzers

🧪 8. Burn-In Testing (Optional)

Objective: Stress the unit to detect early-life failures.

Conditions:

• Operate unit at elevated temperature (e.g., 45–70°C)

• Run for 24–72 hours with cycling loads

• Monitor for abnormal behavior

Typically used for: Medical, automotive, aerospace, and industrial products.

🧼 9. Final Visual Inspection & Cleaning

Objective: Ensure product is clean, defect-free, and cosmetically acceptable.

Actions:

• Wipe off fingerprints, dust, flux residues

• Check for scratches, loose screws, gaps, or misalignment

• Inspect labeling, markings, LEDs

🏷️ 10. Labeling and Serialization

Objective: Apply unique ID for traceability.

Types of Labels:

• Serial number labels

• MAC address, model no., barcodes

• Regulatory markings (CE, FCC, RoHS)

• QR code for field servicing or warranty

📦 11. Final Assembly (Top Cover, Screws, Seals)

Objective: Close the enclosure and secure all parts.

Steps:

• Install top cover or panel

• Tighten all screws with correct torque

• Apply tamper-evident or waterproof seals

• Confirm fit and finish is consistent