Aerospace & Defense

Military-grade PCBs from Sierra Circuits

Our military grade PCBs are manufactured exclusively to meet the defense and space requirements written on the fabrication drawing. The materials we use fulfill the prescribed specifications, like glass transition temperature, decomposition temperature, dielectric constant, CTE, thermal conductivity, vibration resistance, etc., with acceptable tolerances. We check that the designing is done to handle the maximum load current and to survive in the demanding environment. Based on the type of use, we can suggest different specifications.

Aerospace and defense

Sierra Circuits is very familiar with the space addendum for IPC and can help you analyze your designs to make sure they meet the IPC requirements. All of our customers work with us closely in their early design stage to ensure their design is manufacturable and production ready. Additionally, we provide engineering resources to review and create PCB stack-ups (multiple sub-lams, sequential lamination, and staggered microvias) that will meet the manufacturing specifications for defense and space.

Aviation and aerospace

Sierra Circuits is AS 9100 certified. Our primary focus is delivering the highest quality product in the shortest amount of time. As such, we offer internal quality control systems that guarantee error-free boards. Customers get the complete first article inspection report with cross-section and micro-section coupons.

Other applications we serve

We build defense and space PCBs for the following applications:

• Microwave and signal processing system
• Ground station equipment
• Satellite equipment
• Traffic and collision avoidance systems
• Full authority digital engine control systems (FADEC)
• Central air data computers (CADC)
• Flight instrumentation
• Power distribution
• Unmanned vehicles
• Radar control systems
• Jamming systems
• Radio communication systems

Our certifications for military-grade PCBs

Sierra Circuits has the following certifications:

• ITAR
• AS9100D
• MIL-PRF-31032
• MIL-PRF-55110 for GI materials
• MIL-PRF-55110 for GF materials
• IPC J-STD-001E Class 3/ES
• ISO 9001:2015

ITAR

Sierra Circuits is ITAR-compliant. ITAR, or International Traffic in Arms Regulations, is a rule set prescribed by the U.S. government. It controls the manufacture, sale, and distribution of defense and military-related articles, services, and technologies as per the U.S. Munitions List (USML) to ensure safety.

Sierra Circuits does not outsource any subprocess; we own all of our manufacturing from A to Z, providing quality control and transparency.

MIL-PRF-31032

MIL-PRF-31032 is a document that specifies the design rules for military grade PCBs. Every defense and space PCB should adhere to the norms stated in MIL-PRF-50884, MIL-PRF-31032, and MIL-PRF-55110 standards. This gives us the flexibility to implement the best commercial practices—to the maximum extent possible—while producing products that fulfill military performance needs.

The primary concept is as follows:

• The PCB manufacturer creates an internal technical quality review system as per the guidelines given in MIL-PRF-31032.
• A relationship is maintained between the manufacturer and the qualifying activity.
• We provide engineering support to check if your design is mil-spec compliant.

Process of implementing MIL-PRF-31032 specifications

The technical quality review team validates the implemented quality plan. Then, the manufacturer demonstrates its capabilities to produce a PCB for defense and space performance requirements.

Note: Make sure that your PCB manufacturer is capable to provide you the very necessary, very stringent documentation such as MIL-PRF-55110, MIL-PRF-31032, and MIL-PRF-50884.

The testing standards for military-grade boards

There are different electrical test requirements as per MIL-PRF-55110 and MIL-PRF-31032 standards.

Electrical test requirements as per MIL-PRF-31032 standard

• Continuity should be less than 10 Ω.
• Isolation should be more than 2 mΩ and can be managed up to more than 10 mΩ for stringent requirements.
• Voltage should be at least 40 volts unless otherwise specified.

Subject to all group A testing per C=0 sampling plan:

The following tests should be performed on a monthly basis on thermally stressed cross-section of every panel in X and Y direction.

• Solderability
• Ionic contamination
• Dimensional & hole sizes
• Plating adhesion test
• Solder mask adhesion testing
• Legend adhesion
• Surface finish thickness – XRF
• Bow and twist
• Electrical testing (continuity and isolation)
• Copper tensile and elongation should be tested monthly

Electrical test requirements as per MIL-PRF-55110 standard

• Continuity should be less than 10Ω.
• Isolation should be more than 10mΩ, including metal core jobs.
• Voltage should be at least 40 volts unless otherwise specified.

Subject to all group A testing per C=0 sampling plan: The following tests should be performed on a monthly basis on thermally stressed cross-section of every panel in X and Y direction.

• Solderability
• Ionic contamination
• Dimensional & hole sizes
• Plating adhesion test
• Solder mask adhesion testing
• Legend adhesion
• Surface finish thickness – XRF
• Bow and twist
• Electrical testing (continuity and isolation)
• Copper tensile and elongation

How we meet your mil-spec requirements with full traceability

We provide all the military-grade documents

Following is the list of documents that we will provide for your mil-spec board:

• Certificate of conformance
• IPC J-STD-001E
• Material specifications
• Record of calibrated tools used during manufacturing
• Reflow profile copy (included with first article)
• AOI report or visual inspection report
• Photo requirements
• Flying probe or in-circuit testing report
• First article inspection report
• Ionic cleanliness test report

Sierra Circuits delivers high-technology mil-grade PCBs and assemblies on time.
We specialize in DFM analysis that prevent mil-spec issues and offer internal quality review systems that guarantee zero-defect boards. We also provide engineering support to verify if your design is IPC class 3 and 6012 ES or mil-spec compliant.

See our mil-spec capabilities.

Extensive electrical testing
We do not bargain on quality and follow the stringent fabrication criteria that mil-spec boards require – this means constant testing at each step of the manufacturing process, such as cross-section, AOI, BGA X-ray, flying probe, and other electrical tests.

Fab and assembly under one roof
The miscommunications between separate fabrication and assembly shops will cause delays in deliveries and errors in your board. A PCB manufacturer that does not handle assembly won’t run DFA checks to ensure your board can properly be assembled. One single vendor is accountable.

How to get a quote

Let us run DFM/DFA analysis for you and get back to you with a report. You can upload your files securely through our website.

We require the following information in order to give you a quote:

• Gerber, ODB++ or IPC-2581
• BOM and assembly drawings
• Quantity
• Turn time

See our PCB fab and assembly capabilities.