Custom FR4 part
Custom CNC Machining FR4
FR-4 combines electrical insulation, rigid glass-epoxy construction, dimensional stability and flame-retardant performance. Send your drawing, grade, thickness and quantity for an engineering review and transparent quote.
Request an FR4 Parts Quote →FR4 Material Properties
Key Properties of Glass-Epoxy Laminate
Representative datasheet ranges for common unclad woven-glass epoxy laminates at room temperature.
Values depend on supplier grade, glass style, direction, thickness and test method. Tg is not a continuous-use temperature; verify the supplier's RTI or maximum operating temperature for service. Review our FR4 dielectric guide for electrical-property context.
Weldo Machining Capability
CNC Machining FR4 Capability
Drawing-based CNC machining uses carbide or diamond-grade tooling, rigid support and controlled dust extraction to limit delamination, fiber pull-out and edge fray.
| Maximum Part Envelope | 1200 × 1000 × 100 mm |
|---|---|
| Standard Dimensional Tolerance | ±0.10 mm |
| Controlled Critical Tolerance | ±0.05 mm |
| Minimum Wall or Web | 1.00 mm |
| Minimum Hole Diameter | Ø0.80 mm |
| Typical Stock Thickness | 0.20–100 mm |
Final capability is confirmed from the laminate construction, part geometry, edge support and inspection plan.
FR4 Laminate Selection
Select the Right FR4 Grade
Compare the key characteristics, service environment, common parts and finishing options of each laminate type.
Standard FR4
Balanced electrical insulation, stiffness and cost make standard FR-4 the general-purpose choice.
Mid-Tg FR4
Mid-Tg FR-4 provides better thermal and dimensional stability than standard grades.
High-Tg FR4
High-Tg FR-4 provides more thermal-process margin than standard grades, while continuous-use limits remain grade-specific.
Halogen-Free FR4
Halogen-free FR-4 supports projects with defined restricted-halogen compliance requirements.
High-CTI FR4
High-CTI FR-4 offers greater resistance to surface tracking under electrical stress; select the documented CTI class.
Low-Loss FR4
Supplier-qualified low-loss glass-epoxy laminate provides lower Df at a stated frequency for signal-integrity applications.
CAF-Resistant FR4
CAF-resistant laminate is qualified to reduce internal conductive-filament growth in biased, humid printed-wiring structures.
Material Selection
When Choose FR4?
FR-4 is selected when one part must provide electrical insulation and rigid structural support. Final selection depends on the exact supplier grade, voltage, temperature, humidity and certification requirements.
Choose FR4 When
- Electrical insulation is essentialThe component separates conductive parts or supports high-voltage assemblies.
- Rigid sheet construction is suitableFlat plates, panels, fixtures and spacers can be machined from laminate stock.
- Moisture resistance mattersThe selected grade must retain insulation performance in its service environment.
- Flame performance is specifiedUse a listed supplier grade and thickness that satisfies the required rating.
Evaluate Another Material When
- Continuous temperature exceeds the gradeUse a verified high-temperature laminate or engineered ceramic.
- Impact loading is severeFR-4 is rigid but can chip or delaminate under concentrated impact.
- Complex formed geometry is requiredSheet laminate is less suitable for deep molded or highly curved shapes.
- A flame rating is not requiredG10 may provide similar glass-epoxy structural insulation without an FR-4 flame requirement.
Design for Machining
DFM Rules for Clean FR4 Parts
Design the part around the laminate's abrasive glass reinforcement and layered construction.
Use Practical Edge Distances
Keep holes and narrow slots away from unsupported edges to reduce breakout.
Specify Functional Tolerances
Reserve close tolerances for interfaces, hole patterns and inspected features.
Add Internal Radii
Tool-accessible radii reduce cycle time and limit fiber damage in deep corners.
Define Grade Requirements
State Tg, CTI, dielectric, flame and certification needs on the drawing.
Machined FR4 Projects
Custom CNC-Machined FR4 Parts
Prototype, low-volume and repeat-production insulation components machined to your drawing.
Manufacturing and Inspection
From Laminate Review to Final Inspection
Material identity, edge quality and critical dimensions are controlled from process planning through shipment.
FR4 Machining FAQ
Plan Your FR4 Part
What cutting tools are best for CNC machining FR4?
Sharp micrograin carbide suits prototypes and short runs. PCD or diamond-coated carbide provides longer tool life and more stable edges in repeat production. HSS wears rapidly against the glass reinforcement.
How can FR4 workpiece deformation be reduced during milling?
When CNC machining FR4, support thin sheets over the full area, use vacuum or evenly distributed light clamping, and remove stock in balanced shallow passes. Measure critical dimensions after the part reaches a stable inspection temperature.
Is every FR4 sheet UL94 V-0 certified?
No. The recognized flame class depends on the manufacturer, product designation, color and tested thickness. Specify the requirement and verify the supplied stock against the relevant UL record.
What is the difference between FR4 and G10?
Both use woven glass fabric and epoxy resin. FR-4 is specified for flame-retardant performance, while G10 is selected primarily for structural and electrical properties. Do not substitute one for the other without reviewing the exact datasheet and certification needs.
Can threads be machined directly into FR4?
When CNC machining FR4, direct threads suit light loads only when laminate thickness and edge distance are adequate. Use through-bolts, captive nuts or metal inserts for repeated assembly, higher torque or greater pull-out strength.