Conventional PCB Assembly (Through-Hole Assembly) in Portsmouth
Reliable Through-Hole PCB Manufacturing for UK Industries
With over 35 years of experience, Phase One Electronics delivers professional Conventional PCB Assembly (THA) for industries that require durability, mechanical strength and long-term reliability. Our skilled technicians provide accurate soldering, clean lead preparation and dependable inspection for every board we build.
What Is Conventional PCB Assembly?
Conventional PCB Assembly — also known as Through-Hole Assembly (THA) — involves inserting components through drilled holes in the PCB and soldering the leads on the opposite side. This creates strong mechanical joints and long-lasting reliability, making THA ideal for applications exposed to vibration, heat, mechanical stress or high current.
While Surface Mount Technology dominates modern electronics, through-hole assembly remains essential for automotive, marine, industrial, defence and legacy systems. At Phase One Electronics, our trained technicians deliver highly accurate insertion, clean soldering and consistent build quality every time.
- High-current applications
- Products exposed to vibration
- Harsh environmental conditions
- Components requiring strong anchors
- Industrial and automotive systems
- Marine and offshore electronics
- Military and defence equipment
- High-stress mechanical assemblies
- Large capacitors and transformers
- Connectors and high-power terminals
- Older or legacy designs
- Mixed-technology assemblies
Why Choose Phase One Electronics for Through-Hole Assembly?
With more than 35 years of experience, Phase One Electronics is one of the UK’s most trusted providers of Conventional PCB Assembly. Our technicians deliver strong, clean, reliable soldering for applications that demand long-term performance in challenging environments. We combine traditional engineering skill with modern build standards and a commitment to dependable UK manufacturing.
Over 35 years of specialist through-hole experience
Skilled technicians trained to J-STD-001
Full UK-based manufacturing
Ideal for industries where reliability is critical
Accurate, clean and consistent soldering
Support for prototypes, legacy designs and repeat orders
Our Conventional PCB Assembly Process
Through-Hole Assembly requires experience, precision and careful handling. Our technicians follow a structured, quality-focused workflow that ensures every PCB is built correctly, inspected thoroughly and delivered to your exact specifications.
1. Engineering Review & Build Preparation
Before assembly begins, we carry out a detailed engineering review to ensure accuracy, manufacturability and reliability. This early-stage preparation protects your long-term product performance and eliminates potential build issues.
- Bill of Materials (BOM) review
- Assembly drawings and documentation checks
- Lead types and component sizes
- Mechanical fit and spacing
- Soldering requirements and heat considerations
- Review of customer notes, instructions and tolerances
We also highlight any component concerns, spacing issues or possible substitutions for EOL or difficult-to-source parts.
2. Component Handling & Preparation
Through-hole components require careful handling to prevent lead damage, contamination or stress fractures. Our build preparation ensures every part is correctly formed and ready for insertion.
- Lead forming and bending (with proper tooling)
- Lead trimming to correct length
- Polarity and orientation checks
- Cleaning contacts
- Static protection measures
- Organised staging for efficient workflow
Correct preparation is critical for reliable soldering and long-term durability.
3. Component Insertion & Placement
Each component is inserted by hand following customer diagrams, polarity markings and specific build notes. Our technicians ensure alignment and secure placement before soldering.
- Correct orientation (polarity, notches, markings)
- Consistent insertion depth
- Correct lead projection
- No stress on component bodies or pins
We regularly handle precision parts such as transformers, relays, coils, multi-pin connectors, electrolytic capacitors and power semiconductors.
4. Soldering: The Core of High-Quality THA
Through-hole soldering demands skill and experience. We use both hand soldering and wave soldering depending on your project requirements.
Hand Soldering
Ideal for precision builds, heat-sensitive components, small batches and mixed-technology boards. Our process ensures:
- Clean, shiny joints
- Correct solder volume
- Proper wetting and flow
- No bridging or cold joints
Wave Soldering
Used for mid-volume builds and boards with uniform components.
- Consistent results
- Excellent mechanical strength
- High throughput
Our team controls temperature, flux, preheat, dwell time and conveyor speed to ensure reliability and repeatability.
5. Hybrid PCB Assemblies (Mixed SMT & Through-Hole)
Many modern PCBs require both SMT and THA. We specialise in mixed-technology builds and sequence the workflow carefully to avoid thermal damage and rework.
- Correct SMT → THA sequencing
- Heat management procedures
- Controlled soldering techniques
- Masking of heat-sensitive areas
- Cleaning and inspection between stages
We work closely with customers to ensure optimal build order and maximum reliability.
6. Inspection & Quality Control
Inspection is central to our Conventional PCB Assembly service. Every through-hole board undergoes strict quality checks.
- Solder joint quality
- Correct polarity and orientation
- Lead trimming accuracy
- Joint fillet shape and coverage
- Mechanical stability
- Cleanliness and flux residue
- Component seating and stress checks
Our detailed inspections ensure every board is ready for long-term use in demanding industries.
7. Testing & Functional Verification (Optional)
Where required, we perform electrical and functional testing to verify performance.
- Continuity testing
- Functional testing
- Customer-defined test routines
- Firmware programming
- Burn-in testing
We work with customers to establish appropriate testing procedures and fixtures.
Industries That Rely on Conventional PCB Assembly
Through-hole assembly remains crucial in environments where vibration, heat, current or mechanical load demand stronger joints and long-term reliability. Phase One Electronics supports a wide range of UK industries that depend on robust, durable and consistent THA manufacturing.
Marine and Offshore
Automotive and EV Systems
Aerospace, Defence and Military
Industrial Control and Robotics
Medical and Laboratory Equipment
Transportation and Rail
Power Electronics and Energy Systems
Legacy and Obsolete Equipment
Free-Issue or Turnkey Through-Hole Assembly
We offer flexible supply options depending on how you prefer to manage your components. Choose between free-issue builds or a complete turnkey solution where we handle procurement, sourcing and full traceability.
Free-Issue Builds
- Component count and verification
- Moisture-sensitive device (MSD) control
- Secure storage
- Clear documentation and tracking
- Build to your supplied drawings and BOM
Turnkey Builds
- Component procurement and sourcing
- Counterfeit checks and authorised suppliers
- Batch documentation and traceability
- Stock management and planning
- Complete end-to-end assembly
Whether you prefer to supply your own parts or want a fully managed solution, we provide consistent, reliable and professional manufacturing that fits your workflow.
Local UK Manufacturing in Portsmouth, Hampshire
All through-hole PCB assembly is carried out at our Portsmouth facility. UK-based manufacturing gives our customers faster communication, controlled lead times and complete quality assurance throughout every stage of production.