How To Choose G10 Sheet Thickness?

Correct thickness is one of the most important decisions when ordering a g10 glass epoxy sheet for electrical insulation, mechanical support, tooling plates, spacer parts, or CNC-machined components. G10 is made from woven glass cloth combined with epoxy resin under heat and pressure, giving it strong insulation performance, high mechanical strength, and stable dimensional behavior. Thickness affects not only strength, but also machining cost, flatness control, weight, cutting efficiency, and final assembly accuracy.

For manufacturers, G10 sheet thickness selection should not be based only on the drawing size. It should consider load direction, voltage requirement, screw fixing method, tolerance demand, processing method, and the environment where the finished part will work.

Start With The Actual Function

Thin G10 sheets are often used for insulation barriers, washers, shims, PCB support parts, gaskets, and separator plates. These parts usually need good dielectric performance, clean cutting edges, and stable thickness tolerance. Common choices include 0.5 mm, 1 mm, 1.5 mm, and 2 mm.

Medium thickness sheets are usually selected for mounting plates, terminal boards, support blocks, transformer insulation parts, and CNC-machined structural components. Thickness from 3 mm to 10 mm is widely used because it provides a better balance between strength, cost, and machinability.

Thicker sheets are suitable for heavy-duty fixtures, high-load support plates, mold insulation plates, and precision machined parts. Thickness from 12 mm to 50 mm can improve rigidity, but buyers should also review weight, drilling depth, tool wear, and tolerance control before confirming bulk production.

Match Thickness With Mechanical Load

G10 has strong mechanical performance because the glass fabric structure reinforces the epoxy resin matrix. According to commonly referenced IEC 60893 and NEMA LI 1 material data, standard G10 laminated sheets often show flexural strength above 300 MPa, with density generally around 1.8 to 2.0 g/cm³. Actual values may vary by resin content, glass cloth grade, pressing process, and sheet direction.

For parts under light load, thin sheets can reduce material cost and improve processing speed. For parts exposed to clamping force, vibration, repeated assembly, or cantilever stress, a thicker sheet gives better rigidity and lowers the risk of bending or cracking. When screw holes are close to the edge, added thickness can also improve fastening strength.

Consider Electrical Insulation Requirements

Thickness directly affects insulation distance. For electrical parts, the final choice should follow working voltage, creepage distance, clearance design, and safety margin. ASTM D149 is often used for dielectric breakdown testing, while IEC 60893 provides recognized classification guidance for rigid industrial laminated sheets.

Many G10 sheets show dielectric strength in a typical range of 10 to 20 kV/mm under controlled testing conditions. However, finished part performance can be affected by machining scratches, drilled holes, moisture, surface contamination, and sharp edges. That is why our production team recommends confirming both raw sheet thickness and finished-part design before mass cutting.

For high-voltage insulation parts, using only the thinnest possible sheet may create procurement risk. A slightly thicker sheet may offer better safety margin, especially when the part will be used near metal frames, busbars, coils, or power modules.

Review Machining And Tolerance

G10 can be cut, drilled, milled, punched, and CNC processed, but each thickness behaves differently. Thin sheets may need special clamping to avoid vibration during cutting. Medium sheets are easier to process into accurate shapes. Thick sheets require slower feed speed, sharper tools, dust control, and stronger machine stability.

Thickness tolerance is also important. For simple insulation plates, standard tolerance may be acceptable. For stacked parts, sliding structures, positioning blocks, or assembly slots, tolerance should be discussed before production. Tight tolerance can increase grinding time, inspection cost, and lead time, so it should match the real assembly need rather than be set too strictly by default.

Balance Cost And Material Efficiency

A thicker sheet is not always a better choice. Material usage, cutting layout, shipping weight, tool consumption, and production time all increase as thickness grows. For repeat orders, we usually help customers compare drawing requirements with available sheet stock, then suggest a thickness that can reduce waste without affecting performance.

Bulk orders should also consider standard sheet sizes and cutting yield. If the part size does not match the sheet layout well, the same thickness may produce unnecessary offcuts. Early review of drawings, quantity, and tolerance can help reduce waste before production starts.

Check The Working Environment

G10 is valued for low water absorption, good insulation stability, and strong mechanical performance. ASTM D570 water absorption testing is often referenced for laminated insulating materials, and many industrial G10 sheets show low absorption under standard laboratory conditions. However, outdoor humidity, oil contact, heat exposure, and cleaning chemicals may affect long-term use.

For humid electrical cabinets, we suggest smoother edges and proper surface cleaning after machining. For equipment near heat sources, thickness should be reviewed together with heat transfer, compression load, and fixing method. For vibration environments, hole spacing and screw pressure may matter more than thickness alone.

Before Confirming An Order

The most reliable way to select thickness is to review the drawing, working voltage, load condition, machining method, tolerance, and order quantity together. As a bulk G10 sheet supplier, we can support standard sheets, cut-to-size panels, CNC machined parts, drilled insulation plates, and sample confirmation before volume production.

SENKEDA can help customers compare thickness options based on real application needs, not only catalog numbers. When the sheet thickness matches the assembly structure, buyers can reduce material waste, improve processing stability, and make later production easier to repeat.