SMT PCB Assembly vs Through-Hole: Choosing the Right Method | Anzer
Introduction: The Crossroads of Modern PCB Assembly
When it comes to building reliable, high-performance electronic products, one decision can make or break your design: choosing between SMT PCB assembly and through-hole assembly.
This choice impacts not just performance, but also cost, manufacturability, scalability, and long-term reliability.
At ANZER, an electronics design and contract manufacturing company in Akron, Ohio, we’ve helped 200+ customers across 10+ industries make this decision – successfully – over the past 33+ years. With more than 4,000 completed projects, certifications like AS9100D (aerospace), ISO 13485 (medical devices), and ISO 9001 (quality management), we’ve seen firsthand how the right assembly method ensures products are delivered on-spec, on-time, and on-budget.
This guide will help you compare SMT vs through-hole assembly, understand the strengths and weaknesses of each, and decide which one aligns best with your design goals.
Table of Contents
What is SMT PCB Assembly?
Definition
SMT (Surface Mount Technology) is the process of mounting electronic components directly onto the surface of a printed circuit board (PCB). Instead of inserting leads through holes, components are soldered onto pads.
Key Features of SMT
- Miniaturization: Components are small, enabling compact designs.
- Automation Ready: Most SMT processes use pick-and-place machines for high-speed precision.
- Higher Density: More components fit in less space.
- Cost-Efficient at Scale: Ideal for mass production runs.
Typical SMT Applications
- Consumer electronics (smartphones, laptops, wearables)
- Automotive electronics (ECUs, infotainment systems)
- Medical devices requiring compact form factors
- Industrial automation controls where board space is at a premium
What is Through-Hole PCB Assembly?
Definition
Through-hole assembly involves inserting component leads through drilled holes in a PCB and soldering them on the opposite side. It is the older, more traditional method but still very relevant.
Key Features of Through-Hole
- Durability: Strong mechanical bonds for high-vibration environments.
- Prototyping-Friendly: Easier for engineers to hand-solder and rework.
- Heat Resistance: Handles higher thermal and electrical stress.
- Lower Automation: More manual labor compared to SMT.
Typical Through-Hole Applications
- Aerospace electronics (mission-critical reliability)
- Military & defense systems (ruggedness under extreme conditions)
- High-voltage industrial controls
- Large components like connectors, capacitors, and transformers
SMT vs Through-Hole: Side-by-Side Comparison
| Factor | SMT PCB Assembly | Through-Hole Assembly |
|---|---|---|
| Board Density | High (miniaturized designs) | Lower |
| Durability | Good, but weaker than THT under stress | Very strong mechanical bonds |
| Automation | Highly automated, fast | Partially manual, slower |
| Cost (Low Volume) | Higher setup costs | Lower initial costs |
| Cost (High Volume) | Very cost-effective | Expensive due to labor |
| Applications | Consumer, automotive, medical | Aerospace, defense, heavy industry |
| Prototyping | Complex, requires reflow ovens | Easy to hand-solder & test |
| Component Types | Small chips, ICs, resistors | Large connectors, transformers |
How to Decide: SMT, Through-Hole, or Hybrid?Choosing the right method depends on your application, budget, and production needs.
Choose SMT if:
- You need compact, lightweight products.
- Your design has high component density.
- You’re targeting high-volume production.
- You need fast, automated assembly.
Choose Through-Hole if:
- Your product faces extreme vibration, stress, or heat.
- You require large or unique components.
- You’re building prototypes or small-batch runs.
- Your industry demands rugged reliability (aerospace, defense).
Choose Hybrid Assembly if:
- Your design mixes small ICs and large connectors.
- You want the best of both worlds – high density plus mechanical strength.
- You’re scaling from prototype to production, needing flexibility.
At ANZER, we specialize in both SMT and through-hole PCB assembly – and often recommend a hybrid approach to balance performance, cost, and reliability.
The ANZER Advantage: Why Experience Matters
Choosing between SMT and through-hole isn’t just about technology – it’s about who assembles your boards.
Here’s why ANZER is trusted by OEMs across aerospace, medical, industrial, and automotive sectors:
- Certified Excellence: AS9100D, ISO 13485, ISO 9001
- 33+ Years of Experience with 4,000+ projects delivered
- No Minimum Order Quantity – flexible for startups and R&D teams
- In-House Services: Conformal coating, potting, machining, testing
- Scalable Solutions: From prototypes to full production runs
- U.S.-Based Manufacturing in Akron, Ohio -s upporting reshoring initiatives
- Supplier Diversity: MBE & WBE certified for corporate programs
Step-by-Step: How SMT PCB Assembly Works
- Stencil Printing: Apply solder paste to pads.
- Pick and Place: Machines position components at high speed.
- Reflow Soldering: Heat melts solder, bonding components.
- Inspection & Testing: AOI (Automated Optical Inspection) ensures precision.
Step-by-Step: How Through-Hole Assembly Works
- Component Insertion: Leads pushed through drilled holes.
- Wave Soldering: Molten solder bonds leads on the underside.
- Selective Soldering or Hand Soldering: For complex boards.
- Final Inspection: Visual and functional testing.
Cost Considerations: SMT vs Through-Hole
- Tooling Costs: SMT requires more setup (stencils, reflow ovens).
- Labor Costs: Through-hole often requires more manual soldering.
- Yield & Scrap: SMT has higher automation, reducing human error.
- Volume: SMT wins in mass production; THT is cost-effective for low runs.
At ANZER, we offer cost-competitive pricing by optimizing for your project’s volume, timeline, and application requirements.
Industries Driving the Choice
Aerospace & Defense
- Often through-hole for ruggedness.
- Must meet AS9100D certification standards.
Medical Devices
- Combination of SMT for compact circuits and through-hole for connectors.
- Strict compliance with ISO 13485.
Industrial Automation
- Mix of SMT microcontrollers and through-hole relays/connectors.
- High-volume production with long product life cycles.
Automotive
- Heavy use of SMT for miniaturization.
- Through-hole used in high-vibration areas.
FAQ: SMT PCB Assembly vs Through-Hole
Q1: Which is more reliable—SMT or through-hole?
Through-hole is more mechanically reliable in harsh conditions, but SMT is highly reliable for compact, mass-produced electronics.
Q2: Can I mix SMT and through-hole on the same PCB?
Yes—this is called hybrid assembly, and it’s common in aerospace, medical, and automotive products.
Q3: Is SMT always cheaper than through-hole?
Not always. SMT is cheaper at high volume, but through-hole can be more cost-effective for low-volume prototyping.
Q4: What industries still use through-hole assembly?
Aerospace, defense, industrial automation, and power electronics rely on through-hole for durability.
Q5: Does ANZER handle both SMT and through-hole assembly?
Absolutely. ANZER specializes in SMT, through-hole, and hybrid PCB assembly, with full in-house capabilities.
Ready to Choose the Right Assembly Method?
Whether you’re designing a next-gen medical device, building rugged aerospace electronics, or scaling an industrial automation system, ANZER can help you choose and execute the right assembly method.
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Further Reading
- IPC Standards for PCB Assembly – IPC.org
- Aerospace Manufacturing Standards – SAE International
- FDA Guidance on Medical Device Manufacturing – FDA.gov
