Updated table of content
Part 1. Printing and SPI Control
1.1 Paste Chemistry and Alloy Choice
Keeps the alloy/paste basics, but ties every choice to measurable outcomes (printing stability, voiding risk, wetting margin). Defines when “standard SAC305” is fine vs when specialty paste is required. Includes what must be recorded for traceability (lot, expiry, metal load). Avoids marketing paste myths.
1.2 Storage, Thawing, Handling, and Traceability
Turns paste into a controlled material: storage limits, thaw rules, jar time-out, remix rules, and contamination controls. Adds a simple traceability schema (paste lot ↔ job ↔ SPI trend). Defines rejection criteria (viscosity drift indicators, expired exposure). Prevents “mystery paste” defects.
1.3 Stencil Types, Thickness, and Lifecycle
Defines stencil selection by product mix (fine pitch, BTC/QFN, mixed density) and how thickness is decided in real factories. Adds stencil lifecycle controls: incoming inspection, storage, cleaning method approval, and retirement criteria. Introduces a stencil history record to connect wear to print drift. Stops gradual degradation from becoming “normal.”
1.4 Aperture Design Tactics
Keeps the design tactics but forces them into a decision table: reduction rules, window panes, home-plate, step stencils. Links aperture strategy to defect mechanisms (tombstoning, bridging, insufficient solder). Includes a “DFM print-risk checklist” for quoting/NPI. Prevents endless trial-and-error.
1.5 Printer Setup, Cleaning, and Verification Checklist
Converts printer setup into a standardized checklist: alignment, squeegee condition, pressure/speed windows, separation settings. Defines cleaning frequency triggers based on SPI trend, not superstition. Adds a first-panel verification routine and “print stop conditions.” This is how printing becomes deterministic.
1.6 SPI Metrics, Cp/Cpk, and Closed-Loop Rules
Merges your SPI pages into one non-duplicated control system (removes the later “SPI recap” overlap). Defines which SPI metrics matter, what “good” looks like, and what capability targets are required before scale. Adds closed-loop rules: when to auto-adjust, when to escalate, and when to stop. Prevents chasing noise and missing real drift.
Part 2. Placement and Line Control
2.1 Pick-and-Place Architecture as a Capacity and Risk Choice
Keeps “architecture” but reframes it as an operations decision: what the machine can/cannot do for your product mix. Defines constraints that drive downtime: nozzle availability, vision limits, feeder count, and odd-form handling. Links architecture to staffing, changeover time, and maintenance load. Stops “spec-sheet buying.”
2.2 Program Creation and Tuning
Defines programming standards: reference point rules, polarity handling, centroid verification, and fiducial strategy. Includes a tuning sequence that is repeatable (camera calibration → nozzle centering → speed/accuracy balance). Adds acceptance criteria for release to production. Prevents “programmer style differences” from causing defects.
2.3 Feeders, Splicing, and Replenishment System
Turns feeder management into uptime control: feeder qualification, pitch validation, splicing standards, leader length rules. Defines replenishment workflow to avoid line stops and misloads. Includes common failure modes and detection methods. Eliminates “we had the parts but couldn’t run them.”
2.4 Nozzles, Vision, and Pickup Quality Control
Adds the missing layer: nozzle selection matrix, wear checks, vacuum/leak tests, and vision library governance. Defines symptoms of pickup issues (skew, drop rate, repeat defects). Includes a simple periodic audit routine. This is how placement stays stable over months.
2.5 Board Handling, Conveyors, and Line Communication
Keeps line control but adds operational failure points: buffer rules, jam recovery, barcode gates, and handshake logic. Defines what data must be captured at each transfer to preserve traceability. Includes ESD-safe handling requirements at conveyors and manual touchpoints. Prevents “good placement ruined by transport.”
2.6 First Article Execution (Expanded)
Upgrades FA from a concept into an execution script: what to verify on first run (SPI, placement criticals, reflow indicators, AOI coverage). Defines the sign-off artifact and escalation path. Includes “what changes force a new FA.” Stops accidental uncontrolled process changes.
Part 3. Reflow Soldering Control
3.1 Heat Transfer and Zone Control
Keeps the physics but ties it to actionable controls: conveyor speed, zone setpoints, and real measurement discipline. Defines what cannot be inferred (board thermal mass variation, shadowing). Adds the operational rule: profiles are product-specific and must be version-controlled. Prevents “one profile fits all.”
3.2 Profiling Methods and Profile Release Criteria
Defines profiling as a controlled engineering activity with acceptance criteria (ramp, soak, TAL, peak, cooling). Adds probe placement rules, repeatability checks, and when profiling must be repeated. Includes a profile record template. Makes profiling auditable, not anecdotal.
3.3 Air vs Nitrogen as a Cost/Defect Decision
Keeps the atmosphere discussion but forces it into a decision gate: when nitrogen buys margin and when it’s a waste. Links the choice to defect mechanisms (wetting, oxidation sensitivity) and product class. Adds operating controls if nitrogen is used (O2 ppm monitoring, alarms). Prevents “nitrogen as religion.”
3.4 Alloy-Specific Nuances
Keeps alloy nuances but converts them into “do/don’t” settings and risk flags. Defines what changes with low-temp, high-temp, or special alloys (profile windows, flux behavior). Includes compatibility warnings with components and finishes. Reduces metallurgical surprises.
3.5 Reflow Defect Mechanisms and Fixes
Keeps defect mechanisms but structures fixes by controllable levers (print, placement, profile, atmosphere). Includes containment actions vs permanent corrective actions. Defines when to stop and re-profile vs when to adjust upstream. Stops random knob-turning.
3.6 Oven Maintenance, Verification, and Drift Monitoring
Moves part of “maintenance” into where it actually matters: belt tracking, zone uniformity, fan health, flux buildup, and calibration. Defines drift indicators (profile shift, increased defects, AOI trend correlation). Includes a periodic verification plan. Prevents slow degradation from becoming normalized.
Part 4. In-Line Inspection for SMT Line Control
4.1 AOI as a Process Gate (Coverage, False-Call Control, Stop Rules)
Defines what AOI must always check on SMT (polarity, missing, gross solder defects), and what it cannot prove. Sets “stop / contain / keep running” rules based on defect type and rate. Specifies how false calls are reduced without increasing escapes (library discipline, golden sample usage). Keeps it SMT-line actionable, not QMS theory.
4.2 AXI Use Cases (BTC/QFN/BGA Risk, Sampling Rules, Evidence)
Defines when AXI is mandatory (hidden joints / bottom-terminated components) and when it’s optional. Sets sampling plans tied to risk and trend triggers (spike in opens/void indicators). Specifies how evidence is stored (image capture + job/lot linkage) for traceability and later FA/RCA.
4.3 Inspection Programming & Tuning (Recipe Governance + Version Control)
Locks down recipe creation, tuning sequence, and release rules (no “night shift tweaking”). Defines library ownership, revision naming, and what forces re-validation (new paste, stencil change, new component alt). This page stays in SMT because it’s machine + line stability, not QA bureaucracy.
4.4 Routing and Feedback: From SPI/AOI/AXI Signals to Tickets and Downstream Test (merged: old 4.4 + old Part 5 single-page)
Defines the interface outputs from SMT: defect signals, status codes, quarantine tagging, minimal defect taxonomy, and traceability fields. Specifies where the tickets go (rework/containment stream vs downstream test stream) and what triggers SMT line stop vs contain-and-run. States explicitly that test coverage rules, retest limits, MRB/CAPA mechanics live in QA/Box Build books (no duplication). Prevents the same defect from being “handled three different ways” across books.
Part 5. Mixed-Tech Reality: Rework and Through-Hole Integration
5.1 Rework Policy, Limits, and Evidence
Defines rework as a controlled process (not “fix it somehow”). Specifies allowable rework counts, required evidence (photos, X-ray, measurements), and mandatory operator qualification. Includes acceptance criteria linkage (IPC class). Prevents rework from creating latent failures.
5.2 BGA/QFN/BTC Rework Controls
Defines tooling, thermal profiling, component handling, and inspection requirements for BTC-family rework. Includes common failure modes (head-in-pillow, voiding, pad damage) and detection methods. Sets go/no-go criteria. Makes high-risk rework survivable.
5.3 Pin-in-Paste and Mixed-Tech Design Rules
Covers pin-in-paste as the bridge between SMT and THT. Defines when it’s appropriate, stencil/aperture implications, and reflow considerations. Includes design constraints that must be enforced during NPI/DFM. Prevents “THT surprises” after SMT is stable.
5.4 Selective/Wave/Hand Solder Integration
Defines the operational interface: what must be prepared upstream (masking, pallets, flux controls, preheat). Sets minimum controls for solder pot management if wave is used, or station controls if selective/hand solder dominates. Includes defect mechanisms typical for THT (icicles, bridges, insufficient fill). Adds the missing THT reality to an SMT book.
Part 6. Changeover, Maintenance, and Productivity Engineering
6.1 Changeover Reduction (SMED)
Keeps SMED but forces it into measurable actions: internal vs external tasks, staging, kitting, and verification steps. Defines target changeover time bands by product mix. Includes a changeover checklist to prevent misloads. Turns SMED into discipline, not a poster.
6.2 Maintenance and Calibration (Line-Specific)
Keeps maintenance & calibration but expands into a line-level schedule with ownership and evidence logs. Defines what is calibrated vs what is verified, and how often. Includes spare parts policy for critical downtime drivers (feeders, nozzles, sensors). Prevents maintenance debt.
6.3 Line Balancing, Staffing, and Bottleneck Control
Adds the industrial engineering core: takt, bottleneck identification, staffing model, and WIP limits. Defines how to balance placement vs inspection vs test to protect throughput. Includes rules for “when to add labor vs when to fix process.” Prevents permanent firefighting.