G10 vs FR4 both belong to epoxy glass fiber laminates. The core difference between the two materials lies in the use of flame-retardant formulas. This difference directly affects mechanical properties, fire resistance ratings, costs, processing methods, and application scenarios. This article provides a complete comparison in terms of material introduction, classification, mechanical properties, electrical properties, fire resistance, processing technology, cost, applications, and selection, covering all key points for engineering material selection.
Basic Material Introduction
1.1 G10
- G10 is a non-flame-retardant epoxy glass fiber laminate defined by NEMA standards.
- It is made of glass fiber cloth and pure epoxy resin pressed under high temperature and high pressure.
- Main positioning: high-strength structural substrate, prioritizing insulation and mechanical strength.
- Applicable standards: NEMA LI-1, MIL-I-24768/27.
- Flammability rating: UL94 HB, horizontal combustion, non-flame-retardant.
1.2 FR4
- FR4 is a flame-retardant upgraded version based on G10, with phosphorus-nitrogen flame retardants added to meet fire safety specifications.
- Main positioning: electrical insulation and general structural substrate, the mainstream material in the electronics industry.
- Applicable standards: NEMA LI-1, IPC-4101, UL94 and other industry standards.
- Flammability rating: UL94 V-0, self-extinguishing when removed from ignition source, no dripping during combustion.
Material Classification and Grades
Common G10 Classifications
- Standard G10: general high-strength type, non-flame-retardant.
- G10/FR4: flame-retardant modified G10, balancing strength and fire resistance.
- G11: high-temperature enhanced type, with better heat resistance and dimensional stability.
- Colored G10: mostly used for decoration or handles, available in various colors.
Common FR4 Classifications
- Standard FR4: Tg approx. 130°C, for general PCBs and insulation parts.
- Medium Tg FR4: Tg approx. 150°C, suitable for lead-free soldering processes.
- High Tg FR4: Tg above 170°C, used in military, automotive, and high-power equipment.
- Halogen-free FR4: eco-friendly low-smoke type, mostly used in medical and automotive electronics.
- High-frequency low-loss FR4: for high-speed signal and communication equipment.
Core Performance Comparison
3.1 Mechanical Properties
| الخصائص | G10 | FR4 | Difference Description |
|---|---|---|---|
| قوة الانثناء | 380–480 MPa | 310–380 MPa | G10 is 15%–20% higher |
| قوة الشد | 310–380 MPa | 280–340 MPa | G10 performs better |
| Compressive Strength | 290–340 MPa | 250–300 MPa | G10 performs better |
| Impact Resistance | عالية | متوسط-عالي | G10 is about 25% higher |
| ثبات الأبعاد | ممتاز | جيد | Similar levels |
| Water Absorption | Approx. 0.1% | Approx. 0.1%–0.2% | G10 is slightly lower |
3.2 Fire Resistance and Thermal Properties
- G10 has no flame-retardant effect; it burns continuously in open flame and cannot be used in fire-protection required applications.
- FR4 meets UL94 V-0 rating, self-extinguishing within 10 seconds after leaving ignition source, complying with safety standards for electronic and electrical products.
- Long-term operating temperature for both is 130–150°C; high-Tg versions can exceed 170°C.
3.3 Electrical Properties
- Dielectric strength: both are 15–50 kV/mm, at the same level.
- Dielectric constant: 4.2–4.8 at 1MHz.
- Overall, FR4 has more consistent electrical insulation, making it more suitable for PCBs and high-voltage insulation components.
Summary of Advantages and Disadvantages
Advantages of G10
- Higher mechanical strength, better bending and impact resistance.
- No flame retardants, slightly better weather resistance and water resistance.
- Rich color options for appearance parts such as decoration and handles.
- Pure epoxy system, smoother surface after processing.
Disadvantages of G10
- Non-flame-retardant, cannot be used in fire-protection required applications.
- Less widely supplied than FR4, longer lead time for some specifications.
مزايا FR4
- V-0 flame rating, complies with global mainstream safety standards, wider application range.
- Standard material in electronics industry, lower cost and stable supply.
- Complete range of grades for different needs: normal temperature, high temperature, high frequency, halogen-free.
- Mature PCB manufacturing process, best compatibility for etching, drilling, and lamination.
Disadvantages of FR4
- Slightly lower mechanical strength than G10 due to flame retardants.
- Slightly higher water absorption than pure G10 under high temperature and humidity.
Supported Processing Technologies and Precautions
G10 and FR4 have similar processing characteristics; both are highly abrasive and require hard cutting tools.
Common Processing Technologies
- Cutting: التفريز باستخدام الحاسب الآلي الرقمي, waterjet cutting, laser cutting; FR4 is more suitable for laser processing.
- Drilling: high-speed drilling with carbide drills, focusing on smooth chip removal.
- Milling: dry or with minimal coolant to avoid delamination.
- Sanding: using abrasive belts or grinding wheels; matte or textured finishes available.
- Surface treatment: screen printing, painting, bonding; epoxy adhesive is preferred.
Processing Precautions
- Tools must be carbide or diamond-coated; glass fiber wears tools rapidly.
- High spindle speed and low feed rate are recommended to reduce chipping and delamination.
- Control heat dissipation to avoid resin carbonization or delamination from overheating.
- Glass fiber dust is harmful; dust extraction and protective equipment are required.
- FR4 special note: flame retardants may release trace gases at high temperatures; ensure ventilation during laser cutting.
- G10 special note: non-flame-retardant, avoid direct contact with open flame or high-temperature welding.
Typical Application Fields and Components
G10 Applications
- Structural parts: aerospace fixtures, mechanical gaskets, brackets.
- Hand tools: knife handles, outdoor tool grips.
- Marine equipment: marine parts, waterproof insulation brackets.
- Sports equipment: skateboards, model structural parts.
- Insulation parts: high-voltage insulation gaskets in non-fire-protection areas.
FR4 Applications
- PCB substrates: consumer electronics, industrial control, automotive, communications equipment.
- Electrical insulation: motor slot wedges, transformer insulation, isolator switches.
- Structural parts: equipment panels, heat dissipation gaskets, test fixtures.
- Automotive electronics: BMS insulation boards, lamp brackets.
- New energy: battery pack insulation, busbar insulation sheets.
مقارنة التكلفة
Sheet Price (per kg, standard thickness 1–3mm)
- FR4: 4.6–5.0 USD/kg
- G10: 5.0–6.5 USD/kg
- Price difference: G10 is 10%–30% higher than FR4
Processing Cost
- CNC and drilling costs: nearly the same for both.
- G10 causes slightly less tool wear and better processing stability.
- In PCB production, FR4 has significantly lower overall cost and more mature processes.
Selection Guide
- Fire safety compliance required, for PCB or electrical insulation → choose FR4.
- Higher strength, colored appearance, underwater or non-fire-protection structures → choose G10.
- Budget limited, mass production → choose FR4.
- Military/aerospace structural parts, handles, wear-resistant parts → choose G10.
الخاتمة
G10 and FR4 are homologous and heterogeneous epoxy glass fiber materials.
- G10 focuses on pure structural strength: higher strength but non-flame-retardant.
- FR4 focuses on flame retardancy and versatility: meets safety standards and wider applications.
G10 is superior in mechanical performance, while FR4 is better in fire resistance and electrical compliance. FR4 has a lower cost, and the two are similar in processing difficulty. For engineering selection, it is recommended to take flame retardancy requirement as the first criterion, then finalize the choice based on strength needs, budget, and appearance requirements.
