1. Start by Asking: Does My Design Really Need a Thick Board?

Picture these situations:

• Your circuit board visibly sags in the middle after mounting a large heatsink

• Solder joints develop fine cracks during vibration testing

• The board heats up too quickly when power components operate

• A large board feels "flimsy" or unstable

If you've encountered these issues, a thick PCB might be the solution. But first, let's clarify what "thick" actually means.

2. Thickness Standards: From Regular to "Heavy Duty"

1.6mm - Industry standard, chosen for 90% of consumer electronics
2.0mm - Entering "thick board" territory, a common upgrade choice
2.4mm - Typical for industrial applications
3.0mm and above - For special needs like heavy-duty equipment or extreme environments

These measurements refer to the total finished thickness, including all insulating layers, copper layers, and protective coatings.

3. Three Core Advantages of Thick Boards (Only Effective When Applied Correctly)

Advantage 1: Significantly Improved Mechanical Strength

A thick board is like thicker steel—it better:

• Resists bending and deformation, especially in large designs

• Supports heavy components (think large transformers or heatsinks)

• Maintains flatness when secured with multiple screws

• Protects solder joints in vibrating environments

Real Case: An industrial controller client found cracks around BGA chips after vibration testing on 1.6mm boards. After switching to 2.4mm boards, they passed all tests.

Advantage 2: Better Thermal Performance

Thicker material means:

• Greater thermal mass, slower temperature rise

• Better heat distribution, preventing hot spots

• A more stable foundation for cooling solutions

Note: If heat dissipation is the primary concern, metal-core boards might be more suitable. Thick FR-4 boards strike a balance between cost and performance.

Advantage 3: Enhanced Electrical Stability

In some designs, thickness affects:

• Interlayer insulation (important for high-voltage applications)

• Impedance control accuracy (critical for RF circuits)

• Signal integrity (reduced crosstalk)
  

4. Five Product Types Best Suited for Thick Boards

1. Power Supply Equipment

Switching power supplies, UPS systems, power converters—these typically need to:

• Carry high current through thick copper traces

• Support heavy magnetic components

• Manage heat effectively

2. Industrial Control Equipment

PLCs, motor drives, automation controllers face:

• Continuous vibration in factory environments

• Extreme temperature variations

• Reliability requirements spanning years

3. Automotive Electronics

Particularly modules near engine compartments:

• Constant vibration during vehicle operation

• Temperature ranges from -40°C to 125°C

• Reliable installation in confined spaces

4. Test and Measurement Instruments

Oscilloscopes, spectrum analyzers, precision measuring equipment:

• Extremely sensitive to微小变形

• Require long-term stable measurement platforms

• Often include heavy connectors

5. Outdoor LED Lighting

High-power LED fixtures:

• Need to quickly conduct heat away from chips

• Support external heat dissipation structures

• Resist environmental temperature changes

5. Four Technical Points You Must Know When Designing Thick Boards

Point 1: Material Selection is Critical

Materials suitable for regular boards might not work for thick ones:

• Prepreg resin content must be just right

• Thermal expansion coefficients should match across layers

• Special lamination processes might be needed

Point 2: Drilling Process Needs Adjustment

Drilling small holes in thick boards is more challenging:

• Requires sturdier drill bits

• Speed and feed rates need recalibration

• Hole wall quality needs special attention

• Deep holes may require special techniques

Point 3: Plating Uniformity Must Be Monitored

Ensuring even copper coverage inside holes:

• Plating solution circulation must be thorough

• Current distribution might need optimization

• Center sections often risk insufficient copper thickness

Point 4: Warpage Control Requires Advance Planning

Thick boards warp more easily because:

• Temperature differences between inner and outer layers are greater during cooling

• Effects of material asymmetry are amplified

• Control is needed from both design and process perspectives

6. Cost Analysis: Where Does the Extra Money Go?

Direct Cost Increases

• Material costs: 20%-100% more material used

• Processing costs: Longer manufacturing time, more complex process control

• Testing costs: Possibly more testing to ensure quality

Indirect Influencing Factors

• Yield: Initial production yield might be lower

• Lead time: May require longer production cycles

• Minimum order quantity: Some factories have higher MOQs for thick boards

Price Reference Range:

• 2.0mm boards: 15%-30% more expensive than 1.6mm

• 3.0mm boards: 40%-80% more expensive than 1.6mm

• Specifics depend on design complexity and order quantity

7. Decision Checklist: 8 Questions to Guide Your Choice

Answer these questions honestly before deciding:

1. How heavy is the heaviest component? Over 50g warrants considering thick boards

2. How large is the board? Length over 20cm suggests considering thicker options

3. What's the vibration environment? Continuous vibration requires more robust designs

4. How many mounting points are there? Multiple fixation points demand better flatness

5. What's the power density? High heat density needs better thermal management

6. What's the operating voltage? High-voltage applications require thicker insulation

7. What's the expected lifespan? 10+ year lifespans demand more reliable structures

8. What's the budget? Is the cost increase acceptable?

If three or more answers point toward needing reinforcement, thick boards deserve serious consideration.

8. Practical Alternatives (You Don't Always Need Uniform Thickness)

If budget is tight or only局部 areas need reinforcement, consider:

Option A: Local Reinforcement

• Increase thickness in specific areas (step-board design)

• Add metal stiffener bars

• Use support pillars or stiffeners

Option B: Design Optimization

• Adjust component placement to reduce concentrated loads

• Optimize fixation point locations and quantity

• Select appropriate material grades

Option C: Process Improvements

• Employ better soldering processes

• Add protective coatings

• Improve heat dissipation paths

9. Key Questions for Communicating with Manufacturers

When you decide to use thick boards, asking these questions yields more useful information:

Ask about capabilities:

• "What thicknesses do you most commonly produce?"

• "What's your lamination process for 2.4mm boards?"

• "What special measures do you take for drilling and plating thick boards?"

Ask about quality:

• "How do you control warpage in thick boards?"

• "How do you ensure plating uniformity in thick boards?"

• "What special tests do you perform on thick boards?"

Ask practical questions:

• "Based on my design, what thickness would you recommend?"

• "How does increased thickness affect lead time?"

• "How feasible is small-batch production of thick boards?"

10. Recommended Process from Design to Production

Phase 1: Concept Validation (1-2 weeks)

• Use standard boards for functional verification

• Assess mechanical and thermal requirements

• Determine if thickening is necessary

Phase 2: Prototype Development (2-3 weeks)

• Produce test boards in 2-3 thicknesses

• Conduct mechanical, thermal, and electrical tests

• Collect actual data for decision-making

Phase 3: Small Batch Validation (3-4 weeks)

• Produce 50-100 boards at final thickness

• Complete comprehensive testing and reliability verification

• Confirm design and process feasibility

Phase 4: Mass Production Preparation (4-8 weeks)

• Optimize production processes

• Establish quality control standards

• Prepare for volume manufacturing

Final Recommendations

Thick PCBs aren't a simple case of "thicker is better"—they're an engineering decision for specific needs. They address mechanical strength, heat dissipation, and stability issues but increase cost and manufacturing complexity.

The best choice starts with clear requirements analysis. Understand what environment your product will face, what stresses it must endure, how long it needs to work, then select the thickness that just meets these needs—not insufficient, not excessive.

Remember, good design isn't about using the thickest board, but the most appropriate one. Sometimes, clever design optimization is more effective and economical than simply adding thickness.

If you're hesitating between several thickness options, a simple principle is: start with the thinnest design that achieves functionality, and only increase thickness when testing proves it necessary. This controls costs while ensuring reliability.