Four aerospace and defense board types
Avionics controllers, satellite payloads, radar RF assemblies and 10 U.S.C. 4873 covered defense subsystems share an IPC-6012 Class 3 baseline but differ in laminate, thickness and documentation. The starting points below come from the Tecsply stackup selector.
| Board type | Typical layers · thickness | Laminate starting point | Glass |
|---|---|---|---|
| Avionics controller (DO-160 environment) | 10–20 · 2.0–3.2 mm | High-Tg FR-4 (Tg ≥ 170 °C), CAF-resistant, Class 3 | Low-CTE E-glass; T-glass on boards over 3.0 mm |
| Satellite / space payload | 8–16 · 1.6–2.4 mm | Polyimide or high-Tg FR-4, Class 3A | Low-CTE E-glass; T-glass on boards over 3.0 mm |
| Radar / phased-array RF | 10–20 · 2.0–3.2 mm | Hybrid: RO4350B / RO3003 RF layers over high-Tg core | Low-CTE E-glass in the FR-4 section |
| Defense subsystem (10 U.S.C. 4873 covered) | 10–20 · 2.0–3.2 mm | High-Tg FR-4, Class 3, loss grade by data rate | Low-CTE E-glass; T-glass on boards over 3.0 mm |
Aerospace build envelope
Every Tecsply aerospace build is specified to IPC-6012 Class 3 or 3A, including 100 thermal-shock cycles per IPC-TM-650 2.6.7.2, with laminate Tg of at least 170 °C and lot-level traceability of laminate and foil. The envelope below is the baseline we quote from; program requirements tighten it.
| Parameter | Requirement |
|---|---|
| Performance class | IPC-6012 Class 3 / 3A |
| Laminate Tg | ≥ 170 °C FR-4 · polyimide ≥ 250 °C |
| Thermal cycling (program-specified) | −55 °C to +125 °C, typically 1,000 cycles |
| Thermal shock (IPC-TM-650 2.6.7.2) | 100 cycles, ≤ 10% resistance change, no barrel cracks |
| CAF resistance | Required on all Class 3 builds |
| Copper | 1–6 oz, wrap plating on PTH |
| Traceability | IPC-1782, level per program (typ. M3 / P3), lot-level CCL and foil |
| Country of origin | Taiwan / Japan / Thailand / Vietnam / Malaysia; fabrication site and ownership documented |
Thermal cycling, z-axis expansion and PTH reliability
On a 2.4–4.0 mm avionics or satellite board, z-axis expansion of the laminate is the main driver of plated through-hole barrel cracking in IPC-6012 Class 3 thermal-shock testing. The resin expands through the thickness of the board far more than the glass-reinforced plane does, and a copper barrel running through that thickness is stretched on every heating cycle. After enough cycles the barrel, or its joint with an inner-layer pad, cracks.
For thermal-cycling boards the first CCL question is therefore not Df but z-axis CTE and Td (decomposition temperature). We specify Tg ≥ 170 °C, Td ≥ 340 °C and z-CTE below 3% total expansion (50–260 °C) on any board that will see lead-free rework, and polyimide when the operating envelope passes 200 °C. The glass decision follows: T-glass or low-CTE E-glass constructions cut expansion further, and we treat that choice as a reliability decision and document it in the first-article report.
Thickness and drill size interact with all of this. A thicker board with a smaller hole has a higher aspect ratio, which makes the barrel harder to plate evenly and puts more strain on a thinner copper wall. Use the stackup thickness calculator to check total thickness and aspect ratio against your smallest drilled hole before the review.
CAF resistance
Conductive anodic filament (CAF) growth is a failure mode in which copper migrates along a glass fiber between two conductors under bias and humidity, and Tecsply requires CAF-resistant laminate on all Class 3 builds. The risk rises as hole-to-hole spacing shrinks and as the board sees long powered life in humid or condensing environments, which describes most avionics and defense hardware. CAF resistance is a property of the resin system, the glass finish and the fabricator's drilling quality together, so we specify the laminate by name and review the fabricator's drill and desmear process as part of qualification.
Radar and RF hybrid stackups
Phased-array and radar RF sections use PTFE or ceramic-filled laminates with Df around 0.001 (RO3003, RO4350B class), usually as one or two RF layers bonded over a high-Tg FR-4 or Megtron core. The hybrid keeps the expensive, harder-to-process RF material where the antenna feed or RF routing needs it, and keeps the digital and power layers on a laminate the fabricator can drill and plate at Class 3 yields. The bond between the two material families is the critical step, and we confirm the fabricator has laminated the specific combination before the order.
Country of origin: 10 U.S.C. 4873, IPC-1782 and IPC-1791
From January 1, 2027, 10 U.S.C. 4873 bars the Department of Defense from acquiring a covered printed circuit board from a covered nation: North Korea, China, Russia or Iran. The advance notice of proposed rulemaking issued on July 2, 2026 (comments closed August 31, 2026) proposes to test the geographic point of fabrication of bare and partially manufactured boards, backed by an Independent Hardware Assurance Framework built on ISO/IEC 20243, IPC-1782 (traceability) and IPC-1791 (trusted designer, fabricator and assembler), with certifications flowed down to every subcontract tier and verification records kept for 10 years.
Our fabrication base in Taiwan, Japan, Thailand, Vietnam and Malaysia is outside the four covered nations. Because legal commentary on the rule also discusses entities controlled by covered nations, and several Southeast Asian fabricators have parent companies elsewhere, we document each partner's ownership as well as its location, and assign defense work only to partners cleared on both. We structure records so that a prime contractor can demonstrate compliance without rebuilding the paper trail. Every Tecsply aerospace order ships with:
- the material declaration, down to laminate family, glass style and copper weight;
- IPC-6012 Class 3 or 3A inspection records and microsection reports;
- a country-of-origin package covering the bare board, the laminate and the copper foil, with the fabricator's ownership disclosure;
- lot-level traceability records built to IPC-1782.
Our partner fabricators are selected to build to IPC-6012 Class 3 and IPC-1782 traceability requirements. Tecsply does not claim certification on its own behalf; partner certificate numbers are listed in the quote package.
Titanium, aluminum-lithium and superalloy parts
Alongside Class 3 boards, Tecsply supplies machined parts in 3 aerospace alloy families: Ti-6Al-4V titanium, third-generation aluminum-lithium, and Inconel 718 / 625 nickel superalloys, each bought to a named AMS or producer specification with the mill certificate and melt source recorded per lot. Titanium and nickel alloys fall under the DFARS 252.225-7009 specialty-metals clause, so their melt source is part of the quote, not an afterthought. See specialty metal parts for grades, specifications and machining notes.
Covered-nation sourcing commitment
Tecsply commits that every board and metal part it supplies for a US defense or aerospace program is made outside North Korea, China, Russia and Iran, by a partner that is not owned or controlled by an entity in those four countries. The commitment has seven parts:
- Fabrication site. No board Tecsply supplies for a US defense or aerospace program is fabricated, in whole or in part, in North Korea, China, Russia or Iran.
- Fabricator ownership. Those boards are assigned only to partner fabricators that are located outside the four covered nations and are not owned or controlled by an entity in them, or by an entity on the Department of Defense Section 1260H list.
- Evidence on every shipment. The fabricator and fabrication site are named on every certificate of conformance, with lot-level laminate and copper foil records.
- Contract flow-down. The same conditions are written into our purchase terms with each partner fabricator and flowed down to any subcontracted process.
- Our own ownership. Tecsply Inc. is a Delaware corporation owned by Smilden Inc, whose ultimate parent is a Taiwan company with no investment from any covered nation. Beneficial-ownership details are provided to customers on request in SF-328 format.
- Metal parts. Raw material for titanium, aluminum-lithium and superalloy parts is not melted in the four covered nations; for programs under DFARS 252.225-7009, titanium and nickel alloys are melted in the United States or a qualifying country, with the mill certificate for every lot.
- Change notice. If any of these facts changes, affected customers are notified before the next shipment.
This is a contractual sourcing commitment, not a government certification. When the final DFARS rule implementing 10 U.S.C. 4873 takes effect, the program-specific certifications it requires will be provided alongside it.
Aerospace and defense FAQ
These four questions cover the requirements a program auditor or prime contractor most often asks about; the full list is on the FAQ page.
What PCB requirements apply to aerospace and defense boards?
Aerospace and defense multilayer PCBs are usually built and inspected to IPC-6012 Class 3 or 3A, which includes 100 thermal-shock cycles per IPC-TM-650 2.6.7.2 on test coupons. They use high-Tg (170 °C and above) or polyimide laminates, often against program-specified thermal cycling between −55 °C and +125 °C, require CAF-resistant materials, and increasingly need country-of-origin traceability. From January 1, 2027, 10 U.S.C. 4873 bars the Department of Defense from acquiring covered PCBs from North Korea, China, Russia or Iran.
What does 10 U.S.C. 4873 require from a PCB supplier?
From January 1, 2027, 10 U.S.C. 4873 bars the Department of Defense from acquiring a covered printed circuit board from a covered nation: North Korea, China, Russia or Iran. The advance notice of proposed rulemaking of July 2, 2026 (comments closed August 31, 2026) proposes to test where bare and partially manufactured boards are fabricated, backed by an Independent Hardware Assurance Framework built on ISO/IEC 20243, IPC-1782 (traceability) and IPC-1791 (trusted designer, fabricator and assembler), with certifications flowed down to every subcontract tier.
In practice a prime contractor needs to show where the bare board was fabricated, trace the laminate and copper foil lots behind it, and hold certifications from every tier. Tecsply's partner fabricators are located in Taiwan, Japan, Thailand, Vietnam and Malaysia, outside the four covered nations, and because ownership and control may also be examined we document each partner's ownership as well as its location. Each aerospace or defense order ships with an origin package for the board, the laminate and the foil. Whether a specific program is a covered system, and the final certification requirements, are set by the statute and the final DFARS rule; confirm them with your contracting officer.
When should an aerospace board use polyimide instead of high-Tg FR-4?
High-Tg FR-4 with Tg of 170 °C or above, Td of 340 °C or above and total z-axis expansion below 3% (50–260 °C) covers most avionics and defense boards, including boards that will see lead-free rework. Polyimide laminates, with Tg of 250 °C and above, are specified when the operating envelope passes 200 °C, and are a common choice for Class 3A satellite and space payload boards. Polyimide costs more and is harder to process, so we recommend it only when the thermal envelope requires it.
What is the difference between T-glass and E-glass in a PCB laminate?
E-glass is the standard reinforcement in FR-4, with a fiber Dk of about 6.8 at 1 GHz and a CTE of about 5.6 ppm/°C. T-glass is a high-silica, high-modulus glass with a CTE of about 2.8 ppm/°C, half that of E-glass, and a tensile modulus of about 86 GPa against 75 GPa for E-glass (Nittobo published values). Choose T-glass when warpage and dimensional stability limit the design, such as boards under packages larger than 60 mm or thick boards with many plated through-holes. For the lowest dielectric loss, NE-glass is usually the better reinforcement.
Check the stackup, then send us the program requirements
Check total thickness and aspect ratio in the calculator, then send the operating envelope, class, layer count and program origin requirements for a stackup review.
References
- IPC-6012 (rigid PCB qualification and performance), IPC-1782 (traceability), IPC-1791 (trusted electronic designer, fabricator and assembler requirements), IPC-TM-650 2.6.7.2 (thermal shock, thermal cycle and continuity); ISO/IEC 20243.
- 10 U.S.C. § 4873, Additional requirements pertaining to printed circuit boards (uscode.house.gov); DFARS Case 2022-D011 advance notice of proposed rulemaking, 91 FR 40508 (July 2, 2026), comments closed August 31, 2026; Crowell & Moring client alert on the ANPR (July 2026).
- Rogers RO3003/RO4350B and high-Tg FR-4 / polyimide supplier datasheets: Tg, Td, z-axis CTE.
- Nittobo Electronic Materials: glass cloth types (E, NE, T).