Base material - TekRabbits | Electronics, AI and Smart Systems

The short answer

What this setting controls

FR-4 is the familiar rigid glass-reinforced laminate used for many digital, analogue and control boards. Flex, aluminium-core, copper-core, RF laminates and HDI materials exist for different mechanical, thermal or signal needs.

Treat material selection as a stack-up decision, not a colour choice. Compare dielectric constant, loss tangent, glass transition temperature, coefficient of thermal expansion, thermal conductivity, bend radius and the availability of a compatible stack-up.

Options in the order form

How the available choices differ

Choice	Use it for	Engineering note
FR-4	General rigid boards	Balanced mechanical, electrical and thermal performance; confirm Tg and stack-up for demanding builds.
Flex circuit	Bending, folding or very low mass	Requires bend-radius, copper type, coverlay and stiffener decisions.
Aluminium / copper core	Heat-spreading LED and power designs	Excellent thermal path but different drilling, isolation and layer constraints.
Rogers / PTFE laminate	RF, microwave and low-loss paths	Choose from the signal-loss model and approved stack-up, not from the material name alone.
HDI	Microvias and very dense interconnect	Needs an HDI structure, controlled lamination sequence and stack-up review.

Compatibility

What can change with this selection

Changing material can change the available layer, thickness, colour, finish and assembly options.
A material name alone is not a stack-up approval; the final build remains subject to technical review.
Recheck layers, thickness, laminate grade, finish, colour and assembly support after changing the material family.

Practical recommendation

How to make the decision

Use FR-4 for a general rigid board unless the design has a documented thermal, RF, flex or density requirement.
Use flex only when the bend path and bend radius are part of the mechanical design.
Ask for an engineering review when a mixed-material or controlled-impedance stack-up is required.

Before release

Check these points before adding the quote to cart

Confirm the selected value matches the released Gerber, drawing, stack-up, BOM or assembly plan.
Review any fields that changed automatically after this selection.
Check the board preview and server-calculated estimate before adding the quote to cart.
Use FR-4 for a general rigid board unless the design has a documented thermal, RF, flex or density requirement.
Use flex only when the bend path and bend radius are part of the mechanical design.
Ask for an engineering review when a mixed-material or controlled-impedance stack-up is required.

Frequently asked questions

Answers for ordering and design review

Is FR-4 a safe default?

For many rigid prototype and production boards, yes. Keep the default when your schematic, thermal design and signal budget do not call for a specialised laminate.

When should I ask for help?

Ask when the board bends, carries substantial heat, uses fast RF links, needs a controlled impedance, or combines different laminate families.

How do I compare RF laminates?

Use the design-value dielectric constant and dissipation factor at the operating frequency, then confirm the actual stack-up, copper roughness and fabrication model used for impedance.

Why is an option disabled?

The current material, geometry, layer count, quantity or another selected process makes that combination unavailable. Change the controlling selection or revise the design package rather than trying to bypass the disabled state.

Can I rely on the online choice as final manufacturing approval?

No. The interface screens known combinations and requests pricing, while final manufacturability remains subject to the released files and technical review.

What should I record outside the order form?

Put controlled requirements in the fabrication drawing, assembly drawing, stack-up, BOM or acceptance plan. Use Special instructions only for a concise pointer to that controlled requirement.

Will changing this update other selections?

It can. The order form re-evaluates compatibility and may replace a now-invalid dependent choice before requesting a fresh server-side estimate. Review every highlighted or automatically changed field.

What if the design requires an option that is not offered?

Do not approximate it with a different label. Recheck the controlling material and geometry, document the actual requirement, and request technical review before placing the order.

Standards and technical references

Use the latest applicable revision and your organisation’s controlled requirements when a standard forms part of product acceptance.