The Heart of PCBA Manufacturing
The SMT (Surface Mount Technology) production line is where bare printed circuit boards become functional electronic assemblies. In Superb Automation's workshop, the line is arranged as a continuous flow — boards enter at the loader and exit as populated, soldered assemblies ready for inspection and testing.
This tour follows the exact path a board takes through our SMT line, station by station. Each machine is listed with its function, key capability, and the quality checkpoint it passes through.
[PHOTO: Wide shot of the complete SMT production line — boards moving between machines on conveyor]
The SMT Assembly Flow
[Loader] → [1] Solder Paste Printer → [2] 3D SPI → [3] High-Speed Chip Shooter ↓ [4] Multi-Function Placer ↓ [5] Pre-Reflow AOI ↓ [6] 10-Zone Reflow Oven → [7] 3D AOI Post-Reflow ↓ [8] 3D X-Ray CT ↓ [DIP Section] [9] Wave Soldering → [10] Through-Hole Assembly ↓ [11] PCBA Cleaning ↓ [12] Conformal Coating → [13] UV Curing ↓ [14] Depaneling → [15] Final AOI → Out
[PHOTO: Annotated diagram or labeled photo of the production line flow]
Station-by-Station Walkthrough
Station 1: Automatic Solder Paste Printer — Classic1008
What happens here: A bare PCB enters the printer and is clamped against a stainless steel stencil. Solder paste (SAC305 lead-free alloy, sourced from original manufacturer) is applied by a metal squeegee blade that presses paste through the stencil apertures onto every pad on the board. The stencil lifts away, leaving precisely metered paste deposits on each pad.
Key capabilities: - Automatic optical alignment (fiducial recognition) — ±25µm positioning accuracy - Stencil cleaning system — dry + wet + vacuum cycle every 10 prints to prevent aperture clogging - Paste temperature control — maintained at 25 ± 1°C in the enclosed print head - Cycle time: approximately 15 seconds per board (excluding stencil cleaning cycle)
What can go wrong here: 60-70% of all SMT defects originate at the paste printing stage. Insufficient paste causes weak joints. Excess paste causes bridging. Misalignment causes tombstoning. This is why the next station exists.
[PHOTO: Classic1008 printer in operation — squeegee moving across stencil]
Station 2: 3D Solder Paste Inspection — S8080
What happens here: Immediately after printing, before any component is placed, the board enters the 3D SPI machine. Using laser triangulation and structured light, this system measures the height, volume, area, and positional offset of every solder paste deposit in three dimensions.
Key capabilities: - 100% pad coverage — every pad on every board is measured - Measurement accuracy: ±1µm in Z (height), ±5µm in XY (position) - Real-time SPC (Statistical Process Control) — trending paste volume over time alerts operators to stencil wear or squeegee degradation before defects occur - Automatic board rejection — if paste fails specification, the board is diverted for cleaning and reprinting before any components are placed
Why it matters: Catching a paste defect here costs a board wash and reprint (~$0.50). Catching it after reflow costs rework or scrap (~$5-50 per board). Catching it at final test costs a failed board, investigation time, and a customer delay.
[PHOTO: S8080 3D SPI machine — board entering inspection zone under laser head]
Station 3: High-Speed Chip Shooter — SM471
What happens here: The board with verified solder paste enters the high-speed placement machine. Component reels are loaded into intelligent feeders on both sides of the machine. A vision system scans each board for fiducials, then the placement head — carrying up to 10 nozzles simultaneously — picks components from feeders and places them on the board at high speed.
Key capabilities: - Placement speed: up to 78,000 CPH (components per hour) - Component range: 0201 (0.6mm × 0.3mm) up to 14mm × 14mm - Placement accuracy: ±40µm at 3σ - Feeder capacity: 120 × 8mm tape feeders - Automatic nozzle change — 6 nozzle types available for different component sizes
What it handles: Chip resistors, chip capacitors, inductors, small transistors, small ICs in SOT/SOIC packages, and LEDs. Essentially, any component under 14mm body size that comes in tape-and-reel packaging.
[PHOTO: SM471 placement head in motion — nozzles picking components from feeders]
Station 4: Multi-Function Placer — DECAN S2
What happens here: After the chip shooter places all small components, the board moves to the multi-function placer for larger, odd-form, and precision components that the high-speed machine cannot handle.
Key capabilities: - Component range: 0402 up to 55mm × 55mm, including BGAs, QFPs, connectors, and large ICs - Placement accuracy: ±25µm at 3σ (fine-pitch) / ±50µm (standard) - Maximum component height: 15mm - Tray feeder capacity: 20 trays for large/odd-form components - Vision alignment: every component is optically inspected before placement — orientation, lead coplanarity, and ball integrity are verified
What it handles: BGA packages, fine-pitch QFPs (0.3mm pitch and below), large connectors, transformers, electrolytic capacitors, and any component too large or precise for the high-speed machine.
[PHOTO: DECAN S2 placing a fine-pitch BGA — close-up of nozzle and vision camera]
Station 5: Pre-Reflow AOI — JCX-830 First Article Inspection
What happens here: Before the board enters the reflow oven, a first-article inspection system checks component placement. This is not the same as post-reflow AOI — the goal here is to catch misplaced or missing components before soldering, when correction is as simple as placing the missing part.
Key capabilities: - First-article verification against BOM and placement file - Checks component presence, orientation, polarity, and position (XY and rotation) - Integrated with the production system — detects feeder loading errors (wrong component in wrong feeder slot)
[PHOTO: JCX-830 first-article inspection — operator reviewing placement verification]
Station 6: 10-Zone Reflow Oven — TEA-1200-DH
What happens here: The board enters the reflow oven on a conveyor belt and passes through 10 independently controlled heating zones — plus 2 cooling zones. The temperature profile is precisely controlled to melt (reflow) the solder paste, form reliable solder joints, and then cool the board at a controlled rate to prevent thermal shock.
Key capabilities: - 10 heating zones + 2 cooling zones (12 total) - Nitrogen atmosphere — oxygen level maintained below 500 ppm for reduced oxidation and improved wetting - Real-time profiling — thermocouples on a sacrificial board measure actual temperatures at critical components - Profile library — stored profiles for different board thicknesses, component mixes, and solder paste types - Lead-free SAC305 peak temperature: 235-250°C (liquidus: 217°C)
The reflow profile:
| Phase | Temperature Range | Duration | Purpose |
|---|---|---|---|
| Preheat | 25°C → 150°C | 60-120 sec | Gradual heating to prevent thermal shock; activate flux solvents |
| Soak | 150°C → 180°C | 60-120 sec | Flux activation — remove oxides from pads and component leads |
| Reflow | 180°C → 245°C peak | 30-60 sec above 217°C | Solder melts, wets surfaces, forms intermetallic bond |
| Cooling | 245°C → 100°C | 60-120 sec | Controlled cooling; rapid enough for fine grain structure, slow enough to prevent thermal shock |
[PHOTO: TEA-1200-DH reflow oven — boards on conveyor entering first zone, nitrogen flow visible]
Station 7: 3D AOI Post-Reflow — AOI Machine
What happens here: After reflow, the board enters a 3D Automated Optical Inspection system. Multiple cameras and angled lighting capture height maps and color images of every solder joint. The system compares each joint against a golden board reference or IPC-A-610 rule set and flags any defect.
Key capabilities: - 50+ detectable defect types (see TAB2 QC details) - 3D height measurement — distinguishes a joint with insufficient volume from one that looks full in 2D - Automatic defect classification — reduces false calls by categorizing defects by type and severity - Integrated repair station — flagged defects are displayed with location and type for the rework operator
[PHOTO: 3D AOI machine — board under inspection, monitor showing detected joint with flag]
Station 8: 3D X-Ray CT — View-X1800
What happens here: For boards with BGA, QFN, or other hidden-joint packages, the X-ray inspection system captures 3D tomographic images by rotating the board and reconstructing slices of every hidden solder joint.
What it detects: Voids inside BGA balls (threshold: <5% per joint), head-in-pillow defects, insufficient ball collapse, bridging under component bodies, and cracked ceramic capacitors. (Full details in TAB2 QC.)
[PHOTO: View-X1800 X-Ray CT — 3D reconstruction of BGA solder balls on monitor]
Station 9: Wave Soldering — JT-450
What happens here: For through-hole components (connectors, large capacitors, transformers) that cannot be soldered in the reflow oven, the board passes through a wave soldering machine. A pump creates a standing wave of molten solder. The board, with through-hole components inserted, passes over the wave — the solder wicks up through the holes by capillary action, forming reliable joints on both sides of the board.
Key capabilities: - Dual wave: turbulent (chip) wave + laminar wave for complete coverage - Lead-free SAC305 solder bar — sourced from original manufacturer (ECO SOLDER BAR M24AQ) - Nitrogen blanket over the wave to reduce dross (oxide) formation - Preheat zones: 2 (top + bottom IR) - Conveyor width: 50-450mm - Solder pot temperature: 255-265°C
[PHOTO: JT-450 wave soldering — board passing over molten solder wave, flux vapor visible]
Station 10: Through-Hole Assembly Stations
Between SMT and wave soldering, through-hole components are manually inserted at dedicated assembly stations:
Component insertion stations with anti-static work surfaces and LED magnifiers
Selective soldering for mixed-technology boards where some through-hole components cannot be wave soldered (temperature-sensitive, or located on the bottom side)
Hand soldering stations with temperature-controlled irons for rework and low-volume through-hole assembly
[PHOTO: Through-hole assembly station — operator inserting components under magnifier lamp]
Station 11: PCBA Cleaning Machine
After all soldering processes, assembled boards pass through an automated cleaning system that removes flux residue, solder balls, and handling contamination. (See TAB2 Ionic Contamination Test for cleanliness verification.)
Station 12-13: Conformal Coating & UV Curing
Boards requiring environmental protection enter the selective robotic conformal coating station (see TAB2 Conformal Coating Inspection for details), followed by UV curing.
[PHOTO: Conformal coating robot applying acrylic coating to PCB — UV light visible]
Station 14: Depaneling — RS-500 Router
What happens here: For panelized boards (multiple identical PCBs on a single panel for efficient SMT processing), the RS-500 depaneling router separates individual boards using a high-speed spindle with minimal mechanical stress — no V-score snapping that could crack ceramic capacitors or damage solder joints.
Station 15: Final AOI
The last automated inspection station — a final optical scan that verifies no handling damage occurred during depaneling, cleaning, or coating. This is the last machine gate before QC laboratory testing.
DIP (Dual In-line Package) Assembly Line
In addition to the SMT line, the workshop includes a dedicated DIP assembly area for through-hole components that cannot be surface-mounted:
DIP insertion — manual and semi-automatic insertion of DIP ICs, connectors, relays, and large capacitors
DIP soldering — selective or wave soldering
DIP AOI — dedicated optical inspection for through-hole solder joints (see equipment page in TAB1)
Post-solder trimming and cleaning
[PHOTO: DIP assembly area — operators at insertion stations, wave solder machine in background]
Production Capacity & Capability Summary
| Metric | Value |
|---|---|
| SMT placement capacity | [ CPH total across all lines ] |
| Minimum component size | 0201 (0.6mm × 0.3mm) |
| Maximum PCB size | [ mm × mm ] |
| Max component height (SMT) | 15mm |
| Fine-pitch capability | 0.3mm pitch (QFP), 0.4mm pitch (BGA) |
| Solder alloy | SAC305 lead-free (standard); leaded available on request |
| Nitrogen reflow | Standard on all production |
| Conformal coating | Acrylic, silicone, polyurethane — selective robotic application |
Continue the factory tour: QC Laboratory | Facility & Environment | Warehouse & Logistics
