Precision Machining
- CNC Machining Service
- CNC Milling
- CNC Turning
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- Machining Screw/Rivet
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- Casting & CNC
- Aluminum Profile & CNC
- Cold Heading & CNC
LML Metal Products Ltd.No. D309, Yunchuang E Valley, No. 3 Huanshi West Road, Tangxia Town, Dongguan City, Guangdong,China
(86) 17833674102dlynn9527@gmail.com
Materials
CNC Machining in FR4
FR4, a fiberglass-reinforced epoxy laminate, boasts superior electrical insulation, high mechanical strength (bending resistance ≥340MPa), and thermal stability (-100°C to 130°C). Its CNC machinability enables precision-machined PCB substrates and insulating components via optimized tooling—tungsten carbide cutters at 100-200 m/min
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FR4
Designers and engineers frequently choose FR4 for CNC machining and CNC milling parts. Makes sense. This all-purpose metal has been proven to offer:
- * Excellent machinability
- * High strength
- * Hardness
- * Heat tolerance
- * Corrosion resistance
- * Superior electrical insulation
- * Low weight
- * Low cost
- * Overall versatility
Description
- Applications
- PCB substrates ∙ Electrical insulators ∙ Switchgear components ∙ Test jigs ∙ RF microwave circuits
- Strengths
- Superior electrical insulation ∙ High mechanical rigidity ∙ Flame retardant (UL94 V-0) ∙ Excellent dimensional stability ∙ Moisture resistance
- Weaknesses
- Brittle fracture tendency ∙ Anisotropic properties (weak Z-axis) ∙ High tool wear during machining ∙ Limited high-frequency performance (>1 GHz)
- Process compatibility
- CNC machining ∙ Laser cutting ∙ Waterjet cutting ∙ Punch pressing
- Surface Treatment
- Solder mask application ∙ Immersion gold/ENIG ∙ HASL finishing ∙ Silkscreen printing
Characteristics
- Price
- $5-15/sheet (1.6mm thickness) ∙ High machining cost (requires diamond-coated tools)
- Lead Time
- CNC: 3-7 days (depending on layer complexity) ∙ No thermal curing required
- Wall Thickness
- Standard: 0.4-3.2mm (Min. machinable: 0.2mm for ≤50mm² areas)
- Tolerances
- Drilling: ±0.05mm ∙ Outline machining: ±0.1mm ∙ Layer alignment: ±0.075mm
- Max part size
- 500 × 600mm (standard panel size) ∙ Custom panels up to 1200 × 1000mm
FR4 Material Processing Technologies
| Process Technology | Process Characteristics | FR4 Type | Applications |
|---|---|---|---|
| High-Temperature Lamination | High pressure (300-500 psi) at 170-190°C | All types | Multilayer PCB construction |
| Precision Drilling | ±0.05mm accuracy with carbide bits | Standard, High Tg | Through-hole vias, component mounting |
| Laser Micromachining | UV laser ablation (355nm), 20-100μm precision | All types | Microvias <0.15mm, HDI PCBs |
| Photolithography | LDI/contact exposure, chemical etching | Copper-clad | Circuit pattern definition |
| Surface Finishing | Electroless nickel immersion gold (ENIG) | All types | Solderable surfaces, contact pads |
| CNC Routing | ±0.1mm dimensional accuracy | Standard, Lead-free | PCB outline cutting |
| Solder Mask Application | UV-curable epoxy LPI coating | All types | Insulation, protection |
Key Technical Points
- High-Temperature Lamination: Core process for FR4, ensures complete curing of epoxy resin under heat and pressure.
- Precision Drilling: Critical for multi-layer PCBs requiring ±0.05mm hole position accuracy.
- Laser Micromachining: Essential for creating microvias less than 0.15mm in high-density interconnect (HDI) designs.
- Surface Finishing: ENIG (Electroless Nickel Immersion Gold) provides optimal soldering surface and oxidation resistance.
- FR4 Type Differences:
- Standard FR4: Glass transition temperatureTg 130-140°C, general purpose
- High Tg FR4: Heat deflection temperature>170°C, for lead-free reflow processes
- Lead-free FR4: Compliant with RoHS requirements, halogen-free formulations
FR4 for Machining
Material Properties & Machining Relevance
FR4—a flame-retardant (UL94-V0) composite of woven fiberglass and epoxy resin—combines high mechanical strength (bending resistance ≥340 MPa) and exceptional electrical insulation
. Its anisotropic structure provides stability in the XY plane but demands careful toolpath planning to prevent Z-axis delamination during cutting or drilling
. Operating temperatures from -100°C to 130°C ensure reliability in electronics, though its brittleness requires specialized tooling to avoid edge chippingMachining Challenges & Best Practices
CNC machining FR4 necessitates diamond-coated carbide tools due to rapid wear from abrasive glass fibers; optimal parameters include spindle speeds of 18,000–24,000 RPM and feed rates of 100–200 m/min
. Critical processes like drilling sub-0.5mm holes or routing thin walls (<0.2mm) require peck cycles and minimized cutting forces to reduce micro-crackingPost-Processing & Precision Control
Achieving tight tolerances (drilling: ±0.05mm; outline: ±0.1mm) relies on temperature-controlled environments to mitigate resin expansion
. Surface treatments like ENIG (Electroless Nickel Immersion Gold) or solder masking enhance conductivity and corrosion resistance for PCB applicationsGET INSTANT QUOTE
Gallery of FR4 Parts Made by LML
The color of anodized finishes may exhibit some degree of variation due to standard alloy tolerance differences. Please refer to the color scheme below to observe the range of available colors.
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LML takes the stress out of manufacturing by guaranteeing the quality and consistency of every part. Each order is dimensionally and visually inspected by our in-house quality control team to make sure it meets the LML Standard. If you’re not satisfied with your order, we’ll remake your parts as fast as possible, free of charge, or refund you - whichever you prefer.
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LML Metal Products Ltd.No. D309, Yunchuang E Valley, No. 3 Huanshi West Road, Tangxia Town, Dongguan City, Guangdong,China
(86) 17833674102dlynn9527@gmail.com
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