Through-Hole Isn’t Old-Fashioned: Where It Still Wins

Jul 24
Manufacturing Process

Through-Hole Isn’t Old-Fashioned: Where It Still Wins

Surface-mount technology transformed electronics manufacturing, but it did not make Through Hole obsolete. For connectors, power components, transformers, rugged assemblies, and many mixed-technology products, the older-looking process can still be the smarter engineering choice.

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Mechanical strength Power components Mixed technology Serviceability
Through Hole component cross-section A connector, power component, and relay mounted through plated holes in a printed circuit board with solder fillets beneath the board. THROUGH HOLE CROSS-SECTION Leads pass through plated holes and are soldered on the opposite side CONNECTOR POWER PART RELAY / TRANSFORMER SOLDER FILLET Electrical + mechanical joint PLATED THROUGH HOLE LEAD RETENTION Useful under physical stress

Through Hole is not a nostalgic alternative to SMT. It is a manufacturing method with a different set of strengths. When a component must carry mechanical load, conduct substantial current, withstand repeated connector cycles, or remain accessible for service, mounting the leads through the board can be exactly what the design requires.

Modern electronics frequently use both methods. Fine-pitch devices and small passives may be placed with SMT, while connectors, relays, transformers, power devices, and selected hardware are completed with Through Hole or other secondary operations.

Quick Answer

Where Through Hole still earns its place

The deciding factor is not whether the technology looks newer. It is whether the interconnection and assembly method match the product’s physical, electrical, production, and service requirements.

01

Connectors and controls

Headers, terminal blocks, switches, and other parts exposed to plugging, pulling, or operator force often benefit from leads anchored through the board.

02

Power and high-current parts

Larger leads, wider spacing, and robust solder joints can support components whose current, voltage, heat, or mass makes a surface-only connection less attractive.

03

Large and odd-form components

Transformers, relays, large capacitors, inductors, and specialty parts may be better suited to insertion and secondary assembly than standard SMT placement.

04

Rugged and serviceable products

Industrial equipment, laboratory instruments, field-serviceable systems, and long-life products may prioritize mechanical retention and repair access over maximum density.

Not Either / Or

SMT and Through Hole solve different problems

Surface mount usually wins when density, automated placement, fine pitch, low mass, and throughput are the priorities. Through Hole becomes valuable when the assembly must manage mechanical force, larger components, substantial electrical load, or service requirements.

SMT is strongest when the design needs:

  • Compact size and high component density
  • Fine-pitch ICs, QFNs, BGAs, and small passives
  • Fast automated placement and repeatable reflow
  • Low component mass and short electrical paths

Through Hole is strongest when the design needs:

  • Mechanical anchoring through the PCB
  • Large leads, power parts, and odd-form components
  • Repeated connector cycles or physical interaction
  • Accessible rework, replacement, or field service

Most real assemblies are mixed-technology

Using SMT for density and Through Hole for mechanical or power-critical parts is not a compromise. It is often the most practical architecture. Micron supports connected SMT and Through Hole production paths for mixed-technology builds, including secondary assembly, inspection, test, and documentation.

Where It Wins

Six applications where Through Hole remains highly relevant

The method is most valuable where the component or product creates demands that go beyond simply making an electrical connection.

Mechanical load

Connectors, switches, and terminal blocks

Parts that users plug into, tighten, press, or pull can transfer force into the PCB. Through-board leads can provide useful retention and distribute that stress more effectively than solder pads alone.

Electrical load

Power supplies and high-current circuits

Power resistors, rectifiers, relays, large inductors, fuse holders, and other components may need larger leads, generous spacing, thermal planning, and solder joints designed for their current and heat profile.

Mass and geometry

Transformers, relays, and large capacitors

Heavy or irregular components may not fit standard pick-and-place or reflow assumptions. Through Hole insertion, fixturing, and secondary soldering can provide a more controlled manufacturing path.

Product environment

Industrial and rugged electronics

Equipment exposed to vibration, handling, long field life, or repeated maintenance may benefit from mechanically retained components and a process planned around workmanship, cleaning, and inspection.

Lifecycle

Legacy and long-life products

Industrial controls, instruments, and replacement assemblies may remain in production for years. Through Hole can support established designs, lower-volume repeat builds, and component-level service without forcing an unnecessary redesign.

Build strategy

Prototypes and specialized low-volume builds

Some prototypes, laboratory systems, and custom equipment benefit from accessible components, manual installation, and easy engineering changes while the design is still evolving.

The Process

A controlled Through Hole build is more than hand soldering

The exact route depends on component mix, volume, solder requirements, cleaning needs, board design, and acceptance criteria. A disciplined process connects documentation, insertion, soldering, inspection, and test.

Review and planning

Confirm BOM, polarity, component height, lead form, hole dimensions, solder type, masking, cleaning, inspection, and test requirements.

Component preparation

Verify parts, form leads if required, prepare hardware, and establish insertion or fixture instructions that protect orientation and spacing.

Insertion and retention

Install components to the drawing and control stand-off, seating, polarity, clinching, support, or temporary fixturing as the assembly requires.

Soldering

Use the appropriate hand, wave, selective, drag, or partner-supported process based on board design, volume, thermal mass, and component limitations.

Trim, clean, and inspect

Control lead trim, residue removal, solder fillets, hole fill, bridges, damage, orientation, spacing, and workmanship acceptance criteria.

Test and final release

Complete electrical or functional test as specified, confirm labels and records, and protect the assembly with appropriate ESD-safe packaging.

Design for Manufacturing

Through Hole quality begins in the PCB and documentation

A robust assembly depends on the relationship among the lead, plated hole, pad, copper connection, board thickness, solder process, and surrounding geometry. These details are easier to address before release than on the production floor.

Lead-to-hole relationship

Hole size, plating, lead shape, tolerance, and board thickness must support insertion and the intended solder process.

Pad and annular-ring geometry

Land size and surrounding copper should support soldering, inspection, rework, and the board’s reliability requirements.

Thermal relief and copper mass

Large planes can draw heat from the joint. Thermal design should support consistent wetting without overheating the component or PCB.

Spacing, height, and keepouts

Provide room for insertion, fixtures, soldering tools, inspection, lead trimming, connectors, hardware, and enclosure interfaces.

Polarity and orientation

Assembly drawings, silkscreen, BOM data, and work instructions should agree—especially for diodes, capacitors, relays, and keyed connectors.

Process compatibility

Identify temperature-sensitive parts, no-wash areas, masking requirements, lead-free or leaded solder, coating, and cleaning limitations.

Mechanical support

Large components may need brackets, adhesive, hardware, stand-offs, or additional retention rather than relying on solder joints alone.

Inspection and test access

Make important joints visible where possible and preserve access for probes, fixtures, measurements, repair, and final system verification.

Know the Boundary

Where Through Hole is usually not the first choice

Through Hole remains useful, but it should not be specified by habit. SMT is normally better for dense digital designs, fine-pitch packages, miniaturization, high automated placement counts, and products where board area and component height are tightly constrained.

Very high component density

Through-board leads and pads consume board area and can complicate routing on multilayer designs.

Fine-pitch integrated circuits

Modern processors, memory, QFNs, and BGAs are designed around surface-mount production.

Maximum automated throughput

Insertion and secondary operations can add labor, setup, handling, or additional process stages.

Low-profile, lightweight products

SMT generally supports thinner assemblies and lower component mass.

RFQ Checklist

What to send for a mixed SMT and Through Hole quote

Clear assembly data helps Micron identify which components require secondary operations, what soldering path is appropriate, and where tooling, inspection, cleaning, or test assumptions need to be confirmed.

Complete BOM

Include manufacturer part numbers, reference designators, approved alternates, and DNI/DNP notes.

Gerbers or ODB++

Provide fabrication data, drill information, board revision, and any stackup or special-process notes.

Assembly drawings

Show polarity, connector orientation, hardware, stand-offs, component height, special spacing, and lead-form requirements.

SMT placement data

Include centroid or pick-and-place data so the complete mixed-technology flow can be planned.

Solder and cleaning requirements

State lead-free, leaded, no-clean, aqueous-clean, masking, coating, and temperature-sensitive component needs.

Inspection and test criteria

Share IPC class, customer workmanship requirements, test procedures, fixtures, programming, reports, and acceptance criteria.

Quantities and schedule

Identify prototype, pilot, or recurring production quantities and any required delivery milestones.

Material model

Clarify whether the project is turnkey, consigned, or hybrid and identify any customer-controlled components.

Workmanship requirements should be defined—not assumed

Through Hole acceptance can involve solder fillet, wetting, lead protrusion, hole fill, component seating, cleanliness, and other customer- or class-specific criteria. Micron supports IPC-A-610 and J-STD-001 Class 2 or Class 3 requirements when specified. For broader context, the Global Electronics Association’s IPC standards overview explains how industry standards clarify expectations for electronics quality, reliability, and consistency.

Related Capabilities
Through Hole Assembly Manual, mixed-technology, and secondary assembly support. SMT Assembly Automated placement, profile-controlled reflow, inspection, and production support. Electronic Manufacturing Services A connected path from design data to assembled, inspected, and documented product. Prototypes & NPI DFM feedback, risk-reduction builds, first articles, pilots, and production transfer. Testing & Programming AOI, X-ray, ICT, functional test, programming, and production records. Electromechanical Assembly Enclosure integration, wiring, hardware, labeling, final test, and pack-out.
Plan the Right Process

The best assembly may use the newest technology—and the proven one

A reliable PCB does not earn extra credit for being entirely surface mount or entirely Through Hole. It succeeds when every component is assembled with a process suited to its electrical, mechanical, thermal, manufacturing, and service requirements.

Micron supports SMT, Through Hole, mixed-technology, prototype, NPI, production, test, programming, and electromechanical integration from our Norwood, Massachusetts facility.

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Preparing for Supply Chain Disruptions: How an Agile EMS Partner Makes the Difference

Nov 11

By Micron Corporation •

In today’s volatile global landscape, supply chain disruptions have become more than just an occasional challenge — they’re the new normal. For OEMs and product developers, that means timelines, budgets, and customer commitments are all on the line when a single supplier or shipping lane falters.

As we move through the final quarter of 2025, many manufacturers are asking the same question: How do we protect our production schedules and ensure we can still deliver? The answer lies in partnering with an agile, responsive, and domestically grounded Electronics Manufacturing Services (EMS) provider.

At Micron Corporation, we’ve built our operations around that exact philosophy — anticipating disruption and designing flexibility into every stage of manufacturing.

The Supply Chain Reality in Late 2025

Even as the global economy steadies post-pandemic, volatility continues to define electronics manufacturing. Component shortages remain an issue in key categories — semiconductors, passives, connectors — as demand from AI, IoT, and EV sectors outpaces supply.

At the same time, geopolitical tensions, logistics constraints, and material price fluctuations continue to challenge even the most carefully planned programs. For OEMs, the ripple effects include:

  • Extended lead times for critical components.
  • Higher costs from expedited shipping or broker sourcing.
  • Unexpected design changes when parts go obsolete mid-project.
  • Missed deadlines that can jeopardize product launches and client trust.

In short, the margin for error has disappeared. The manufacturers that continue to deliver are the ones that can pivot quickly — often with the help of a flexible, well-connected EMS partner.

What “Agility” Really Means in Electronics Manufacturing

Agility isn’t a buzzword — it’s a measurable capability. In our world, an agile EMS partner is one that can:

  1. Adapt production schedules quickly — shifting from prototype to volume, or from one product family to another, without weeks of downtime.
  2. Source components from multiple vetted suppliers, reducing dependence on single-region availability.
  3. Communicate transparently when risks emerge, so OEMs have real-time insight into potential impacts.
  4. Operate domestically, reducing the uncertainty that comes with overseas shipping and customs delays.

At Micron Corporation, this mindset informs everything we do. Our U.S.-based facility in Norwood, Massachusetts is designed for fast response, short production runs, and seamless transitions — whether the project involves Surface Mount, Through Hole, or mixed-technology assemblies.

How Micron Corporation Builds Resilience Into Every Project

  • Supplier diversification: Relationships with multiple distributors and manufacturers for key components ensure qualified alternatives are ready when shortages arise.
  • Early design engagement: Our engineering team collaborates during design to flag at-risk parts and propose footprint-compatible substitutes.
  • Material forecasting: Continuous lead-time analysis enables proactive purchasing of long-lead items.
  • Flexible production capability: Lines and teams are optimized for quick changeovers — minimizing setup loss between products.
  • Transparent communication: Timely updates on supply conditions, allocation risks, and recommended mitigations.

Best Practices for OEMs: Staying Ahead of the Next Disruption

  • Qualify multiple sources early. Build alternates into your AVL and BOM.
  • Plan hybrid inventory models. Blend Just-In-Time with strategic stocking for critical assemblies.
  • Collaborate continuously. Share forecasts and design revisions early to avoid last-minute rework.
  • Prioritize local manufacturing. Domestic builds shorten transit times and reduce geopolitical exposure.
  • Review supply risks quarterly. Conditions change fast — keep mitigation plans current.

What to Ask When Evaluating an EMS Partner

  • What is your sourcing footprint — and do you have multiple suppliers for each key component category?
  • How do you handle sudden lead-time extensions or allocation events?
  • Can you adjust production volumes quickly to meet changing demand?
  • What visibility do you provide into supply chain performance and material status?
  • How do you support Through Hole and mixed-technology assemblies under dynamic scheduling conditions?

Looking Ahead to Q4 and Beyond

As 2025 closes, industry signals suggest the first half of 2026 may bring renewed constraints driven by AI hardware and power electronics. Add election-year trade adjustments, transportation cost fluctuations, and ongoing regional conflicts, and it’s clear that uncertainty isn’t leaving anytime soon.

The key is early engagement and proactive planning. The earlier you involve your EMS partner, the more options exist for alternate sourcing, design flexibility, and production timing. Micron Corporation is helping customers with dual-sourced components, dynamic lot scheduling, and flexible Through Hole production — providing confidence heading into the next quarter and beyond.

Conclusion: Turning Risk Into Readiness

Supply chain disruptions will continue to test manufacturers. With the right partner, those challenges become opportunities to strengthen processes, streamline communication, and accelerate innovation.

At Micron Corporation, our commitment to agility, transparency, and U.S.-based manufacturing helps customers keep building, shipping, and growing — no matter what happens globally.

Contact Us for a Readiness Review

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