Precision-Controlled Soldering for SMT, Through-Hole, and Mixed PCB Assemblies

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ISO 9001/UL Certified
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PCB Assembly Specialists
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97% of PCB Shipped on Time
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98% of PCB Delivered to Spec
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Delivery Guarantee

PCB Manufacturing Process

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How PCB Soldering Fits Into the Full Assembly Process

What Makes OurPCB a Trusted PCB Soldering Service Manufacturer?

Certified to Industry-Defined Soldering and Quality Standards

We are certified to IPC-A-610 Class 2 and Class 3 workmanship standards, covering all solder joints, terminal connections, and component mounting across our SMT, THT, and mixed-technology lines.

All internal process controls follow ISO 9001:2015 and IATF 16949 protocols for electronics manufacturing.

This framework governs our full PCB assembly and soldering services, including document control, first-article validation, and inspection escalation procedures.

Advanced Soldering and Inspection Equipment In-House

We operate dual Fuji pick-and-place machines for high-speed placement accuracy down to ±50 microns, supported by precision stencil printers and nitrogen reflow ovens with controlled peak temperatures of 464 °F (240 °C) for lead-free profiles.

Our wave soldering systems offer dual-wave capability for through-hole components at immersion temperatures up to 482 °F (250 °C).

For inspection, we deploy 3D X-ray, automated optical inspection, in-circuit testers, and 3D SPI for solder paste volume analysis.

Global Reach as a PCB Soldering Service Exporter

As a proven PCB soldering service exporter, OurPCB supplies full board assemblies to OEMs and contract manufacturers across North America, Europe, and Southeast Asia.

We manage export documentation, packaging protocols, and international shipment tracking for turnkey projects.

Our production systems support volume PCB assembly, RoHS compliance, and full traceability for customer-supplied or sourced BOMs.

Full Support for Turnkey and High-Mix Assembly Projects

Our production team manages complex assemblies involving mixed SMT and Through-hole components, specialty connectors, and unique board configurations.

We coordinate procurement, soldering, and test workflows for turnkey builds and multi-stage delivery cycles, ensuring on-time output for prototype and high-mix orders.

In-House Engineering Review of PCB Soldering Requirements

We conduct detailed manufacturing reviews of customer-supplied Gerber files, BOMs, and assembly drawings to identify risks before production.

Our team evaluates pad layout, solder mask clearance, and thermal relief features to match soldering requirements with actual board design constraints.

This review process supports defect prevention and high solder joint yield in every order.

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Vapor Degreasing (For Fine-Pitch Components)

We use vapor degreasing to clean fine-pitch SMT assemblies where low standoff heights prevent rinsing under components. The process heats a fluorinated cleaning fluid such as HFE-72DA until it vaporizes at 58 °C.

Our sealed-chamber systems recover 90% of solvent through closed-loop distillation and vapor filtration. Because no water is used, this PCBA cleaning method prevents capillary trapping and delivers dry, spot-free boards that are immediately ready for conformal coating or inspection.

Aqueous Cleaning (For High-Volume Batch Cleaning)

For high-throughput cleaning, we operate fully enclosed aqueous cleaning systems that combine high-pressure spray with saponified deionized water at 60 °C. These systems target assemblies with solder paste, rosin, or water-soluble flux, removing active ions and organic residue from both sides of the board.

Our InJet platforms use 2.0 bar rotary spray heads for impingement and cascade rinsing with resistivity sensors that maintain <1.56 µg/cm² NaCl equivalent. Each cleaned board is force-dried at 70 °C for 10 minutes to eliminate moisture and prepare the surface for optical inspection or downstream processing. This is the most efficient method for batch-based PCBA cleaning at scale.

Manual/benchtop cleaning (for rework and selective soldering)

When boards require post-assembly rework or selective soldering, we apply a controlled manual cleaning process to treat localized contamination. Technicians begin by applying Decotron T383 or high-purity IPA to the assembly surface, then scrubbing with anti-static brushes at a 45° angle and 250 g pressure.

Flux is then removed using a directional aerosol rinse, and drying is completed with 30 psi filtered air or lint-free polyester wipes. This method allows us to clean the PCBA without subjecting sensitive components to immersion or thermal stress. We document all manual cleaning steps for traceability on high-reliability builds in automotive, medical, and aerospace programs.

How do We Clean No-Clean Flux and Prepare for Conformal Coating?

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Our PCB Soldering Service Capabilities

Reflow Soldering for SMT Components

Our reflow lines support high-density SMT components using nitrogen convection ovens with 4-zone profiles: preheat at 320 °F to 356 °F, soak to 392 °F, peak at 464 °F ±3.5 °F, and controlled cooling. We apply lead-free solder alloys such as SAC305 using precision stencil printers and stainless steel stencils matched to pad geometry.

Solder paste volume is verified with 3D SPI before thermal processing, and final joints are inspected to IPC-A-610 Class 2 and Class 3 standards. This reflow soldering method ensures consistent wetting on all surface mount technology assemblies without warpage or oxidation.

Wave Soldering for Through-Hole and Mixed Assemblies

Our wave soldering systems use dual-wave technology with fluxing, preheating to 266 °F (130 °C), and solder pot immersion at 482 °F (250 °C). Boards move through at controlled speeds between 1.2 and 1.8 meters per minute to maintain optimal dwell time.

We support through-hole technology and mixed assemblies where SMT components are shielded or pre-soldered.

This process delivers full wetting on pin and pad interfaces, preventing bridging and cold joints on high-pin-count through-hole components. Final joints are inspected per IPC-A-610 Class 2 or Class 3 acceptability standards.

Selective Soldering for Sensitive Assemblies

We use selective soldering machines with programmable nozzle control, flux spray heads, and radiant preheat to 212 °F (100 °C) for localized soldering without thermal damage to nearby components. This method is ideal when SMT components already reflowed must be protected during through-hole soldering.

We apply this technique for shielded connectors, plated enclosures, and mixed-material builds. The system maintains ±0.3 mm nozzle precision and controlled dwell to form clean joints on isolated surface mount pads or fine-pitch terminals.

Manual Soldering and Rework Services

Our manual soldering operations support rework and touch-up tasks for fine-pitch leads, connector repair, and component-level updates. Operators use temperature-controlled soldering irons set between 662 °F and 716 °F (350 °C to 380 °C) with optical magnification for joint inspection and alignment.

We perform QFN rework, lifted pad repair, pin replacement, and cleanup of thermal shock failures. Minimum pad-to-pad spacing and part-to-hole spacing are validated at 50 to 100 mils. All manual work is performed to IPC-A-610 Class 3 acceptance criteria using validated repair services procedures.

Inspection and Testing for High-Reliability Builds

Every board is inspected and tested after soldering using automated optical inspection, 3D X-ray, in-circuit testing, and microsection analysis. We classify assemblies to IPC-A-610 Class 1, 2, or 3 based on product requirements, with visual inspection focused on solder joint geometry, component alignment, and lead integrity.

For Class 3 builds, we evaluate cleanliness, mechanical stability, and conformal coating thickness between 25 and 250 microns. These combined methods ensure delivery of a fully verified, production-grade quality PCB that meets critical function and durability standards.

Soldering Materials, Controls, and Process Variables

We support lead-free and SnPb solder systems, with SAC305, SN100C, and Sn63Pb37 alloys selected based on thermal profile, joint strength, and application environment.

Melting points range from 361 °F to 455 °F (183 °C to 235 °C), with matched flux chemistries to reduce oxidation and improve wetting on varied pad finishes. We calibrate stencil thickness from 0.10 mm to 0.18 mm, depending on component density, and apply aperture design rules to prevent bridging and slumping.

All assemblies are cleaned using solvent-safe methods to remove ionic residues and prevent dendritic growth. We evaluate solder mask quality, PCB pad surface finishes, and board layout during DFM review to confirm compatibility with our soldering systems and material limits for each printed circuit build.

Millions of business and innovators use OurPCB

PCB Board Process

Design (1 day)

  • Upload Schematic to Get a Quote
  • PCB Review and Quotation
  • Customer Makes Payment
  • Evaluation & Confirmation of Plan
  • Design Start

Layout (1 day)

  • Layer Stack-up Design
  • Design Rule Setting
  • Component Placement Design
  • Confirmation & Optimization
  • Fanout

Routing (1 day)

  • Fanout Optimization
  • PCB Routing
  • Equal-length Adjustment
  • Routing Optimization
  • DRC Check
  • Routing Confirmation

Optimization (1 day)

  • Silkscreen Adjustment
  • Data Output
  • Customer Final Confirmation
  • Production Debugging
  • Archiving Projects
  • Finish

PCB Board Process

Order Received

  • Component Procurement
  • Preparation
  • PCB Manufacture
  • Make Process Flow

Soldering

  • Solder Printing/Wave Soldering
  • SMT/Plugging
  • Inspection (repair if necessary)
  • AOI (repair if necessary)
  • Transfer

Parts Assembly

  • Manual Assembly
  • PCBCleaning
  • Wire Screw
  • Inspection
  • Repair If Necessary

Finalization

  • Final Confirmation
  • Packing
  • Shipping

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Common Soldering Defects and How We Prevent Them

PCB Soldering Service FAQs

What does a PCB soldering service do?

A PCB and soldering service joins electronic components to a printed circuit board by forming reliable electrical and mechanical connections at each pad location. This can involve automated SMT lines, wave soldering systems, or manual rework using temperature-controlled irons and magnified inspection.

At OurPCB, every assembly service includes matched thermal profiles, component validation, and IPC-A-610 Class 2 or 3 compliance to ensure long-term joint integrity.

What’s the difference between reflow, wave, and selective soldering?

Reflow soldering is used for surface mount assemblies, heating the board through a defined thermal profile to melt solder paste under SMT components. Wave soldering is applied to through-hole assemblies by passing the board over a molten solder wave, which is ideal for high-pin-count headers and sockets.

Selective soldering targets only specific joints using a programmable nozzle, avoiding thermal stress on nearby parts. Each soldering process is selected based on board layout, component density, and reflow compatibility.

How do you handle rework and BGA repair services?

OurPCB performs BGA rework and QFN rework using high-magnification inspection, thermal profiling, and 3D X-ray for alignment verification. Failed BGA packages are removed and replaced using hot gas or IR reflow, followed by controlled BGA reballing.

We apply IPC-guided procedures across all PCB rework services, including pad repair, connector replacement, and rework and repair services for Class 3 assemblies that require exact shape, wetting angle, and joint consistency.

What files do you need to start a PCB assembly and soldering project?

We require Gerber files for the printed circuit board, a complete BOM with manufacturer part numbers, and a centroid file for component placement. If testing is required, include netlists or programming instructions.

As a PCB assembly manufacturer, OurPCB uses these inputs to configure our PCB assembly process and align soldering procedures with pad types, package outlines, and final printed circuit board assembly requirements.

Can you support Turnkey PCB and PCBA Services on Scale?

Yes, OurPCB supports full turnkey PCB and PCBA assembly through two in-house factories, each with over 10,000 square meters of production space.

We manage component sourcing, soldering, programming, functional testing, and final assembly under one roof. Both facilities are ISO 9001 and IATF 16949 certified, with soldering operations performed to IPC-A-610 Class 2 and Class 3 standards.

Our production lines are MES-controlled for traceability and process consistency across prototype and volume PCB assembly.

Ready to Work With a Trusted PCB Soldering Service Manufacturer?

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