Material Processing Tips on CNC Machining FR4 and G10

Learn expert CNC machining tips for FR4 and Garolite G10, including techniques for precision, material handling, and achieving high-quality results.

G10 and FR4 are fiberglass-reinforced laminates well-desired in various industries due to their superior properties in terms of mechanical strength, heat resistance, and electrical insulation. These two composite laminates are widely used in electronics, aerospace, automotive, etc.

Here, to make parts or components of parts for the mentioned industries using G10 and FR4, accurate precision in CNC machining is crucial. Additionally, mitigating challenges like tools ware, delamination, etc., are essential.

Following this, we would like to provide a stepwise guide for CNC machining of G10 and FR4, along with some expert tips.

Basics of FR4 and G10

Garolite Grade 10 and FR4 are composite materials formed by epoxy resin-based bonding of multiple fiber woven glasses. As per industry standards, G10’s ‘G’ represents Garolite, ‘10’ represents the grade, ‘FR’ stands for ‘fire-retardancy,’ and 4 is the grade.

Key Properties of FR4 and G10

G10’s flammability rating is HB, and FR4’s rating is V-0.
G10 and FR4 thermal conductivities are 0.25 W/m-k and 0.28 W/m-k, respectively.
Both of the materials showcase superior mechanical strengths.
The dielectric strength of G10 can reach 550 Volts/mil, while the maximum dielectric strength of FR4 is 900 Volts/mil.
FR4 is more cost-effective than G10.

Common Applications of FR4 and G10

G10 glass epoxy laminate is widely used to manufacture washers, terminal boards, cryogenic components, firearm components, electric items, etc. On the other hand, FR4 is used to produce printed circuit boards, aircraft components, electric insulators, turbine blades, solar panel components, and so on.

Step-by-Step CNC Machining FR4 and G10

This section details the CNC machining processes of G10 and FR4. Considering the base characteristics’ similarities, the same CNC machining process applies to both G10 and FR4.

However, in the CNC machining of Garolite 10 and FR4 glass epoxy laminate, the core differences are inherited in the tool type, feed rate, etc.

Material Preparation

In this pre-machine process, manufacturers must select the right sized, shaped, and thickened sheets or blocks of G10 and FR4 and remove the dust and other contaminants from the surfaces.

If the used G10 or FR4 sheet or block is enormous, we suggest making a pre-cut using a saw to reduce the machining time. In this step, professionals must arrange and wear standard PPE.

CNC Machine Setup

The following tasks need to be performed.

Ensuring the associated clamps, fixtures, supports, etc., are placed appropriately. The machining table needs to maintain a perfect 180 degrees with the floor surface.
Due to the abrasive nature of fiberglass in G10 and FR4, the recommendation is to use carbide or diamond-coated end mills and drill bits. Additionally, considering the desired outcome, compressive drill bits should be used to machine FR4. The compressive drill bits eliminate the risk of delamination in FR4’s CNC machining.
Feeding the designs in the CAM or CAD software towards creating the machining path for rough cuts, contouring, and finishing passes.

CNC Machine Feed Setting

The spindle speed for G10’s CNC machining needs to be set between 15,000 RPM to 30,000 RPM. Whereas the recommended spindle speed for FR4 CNC machining ranges between 16,000 RPM to 60,000 RPM depending on diameter between 0.8 to 3.175.
The tool feed rate varies significantly as per the tools’ diameter and required surface finish. Still, the recommended feed rate for G10 CNC machining is 0.001-0.004 per tooth while the feed rate ranges from 0.001-0.005 per tooth for FR4 CNC machining.
Depending on the desired surface finish, tool diameter, and specific machining operation, FR4’s depth of cut ranges between 0.1 mm to 1 mm. In the same criteria, the depth of cut in G10’s CNC machining must not exceed 12X of the drill bit diameter and 10X of the end mill diameter.

CNC Machining Process

First, it is to be mentioned that in the overall CNC machining processes, the coolant needs to be applied to restrict excessive heat generation, aka eliminating the risks of material crake, tools’ ware, etc. The following are the machining processes of G10 and FR4.

We strongly recommend starting with rough cuts. In this process, the extended edges and portions of the respective materials need to be removed. Upon finishing the rough-cutting activities, the professionals need to remove chips, dust, etc.
Performing the precise contouring or pocketing as per the pre-set feed rates. This process is termed as creating finishing passes.
If the requirement is hole creation, it should be performed carefully while removing chips and dust consistently restricting tool clogging.

Post-machining Process

Smoothing the edges of the desired G10 or FR4 components takes place in this step. To smooth the edges, it is better to use 180-grit medium-coarse sandpaper or 320-grit for finer grit sandpaper.
We highly recommend incorporating standardized quality inspection approaches to ensure the machining outcomes meet the demands.
Coating, special polishing, etc. take place to enhance the aesthetics of the G10 or FR4 glass epoxy laminate components.

Ending the CNC Machining Process

Cleaning the workstation appropriately.
Inspecting the tools to identify any signs of wear and tear. If no issue, the respective tools can be used for the next machining processes.

Challenges in G10 and FR4 CNC Machining

The accommodated fiberglass triggers quick tool wear.
Inappropriate feed speed results in delamination, degrading the structural integrity of the G10 or FR4 component.
Using dull tools and improper cutting speed often result in triggering cracks in the final components.
Excessive heat generation, along with chipping, is a crucial issue.
Excessive vibration of the machine results in low-quality cuts.

Expert Tips for Material Processing: G10 and FR4 Fiberglass Epoxy Laminates

With decades-long experience, our experts at UVTECO provide the following tips to enhance the effectiveness of G10’s and FR4’s CNC machining.

Diamond-coated and solid carbide tools are recommended to use.
Multi-axis CNC machines should be used for complex cuts.
Cutting speed and heat generation must be controlled effectively.
Before smoothing the edges, the materials must be handled carefully to prevent accidents.
Experienced professionals always matter significantly.

Conclusion

We expect that our elaboration on G10 and FR4 CNC machining in terms of material processing will help the professionals, designers, etc. enormously. There are indeed challenges associated with processing G10 and FR4, but these can be mitigated by using our recommendations.

Finally, we strongly recommend that users go to highly experienced manufacturers in the respective industry to get quality G10 and FR4 components. UVTECO is a leading supplier of FR4 and G10 sheets, rods and tubes in China, meantime, we also provide machining services. If you are looking for a trustworthy supplier, contact UVTECO now!