Every aerospace supplier knows that precision isn’t optional—it’s fundamental. Whether delivering components for commercial jets or defense aircraft, meeting exact engineering specifications is the baseline. The aerospace sector doesn’t just demand quality; it demands repeatability, documentation, and traceability across every part delivered. To qualify and remain competitive, manufacturers must demonstrate their capability to deliver exactly what’s specified—nothing more, nothing less.
At the core of this expectation is build to print manufacturing. This approach requires vendors to fabricate parts strictly according to the customer’s engineering drawings, material specs, tolerances, and processing guidelines. The supplier has no role in designing the part but must execute the build flawlessly, in compliance with tightly controlled standards. Understanding and meeting these requirements is what separates approved aerospace vendors from those who never make it past RFQ.
What Is Required in a Build to Print Contract?
Build to print contracts hand over complete design ownership to the customer, making it the supplier’s responsibility to follow the specifications without deviation. The requirements include:
- Engineering Drawing Compliance
Suppliers must interpret and build to complex 2D and 3D CAD drawings. This includes understanding GD&T (Geometric Dimensioning and Tolerancing), material callouts, finishes, and tolerances. - Approved Materials
Only customer-approved materials and sources may be used. Certifications like DFARS compliance or Nadcap material sourcing are often mandatory. - Qualified Processes
Any special processes (e.g., heat treatment, NDT, chemical processing) must be performed by approved vendors and fully documented. - Traceability
From raw material to final inspection, every step must be traceable with documented records, lot numbers, and inspection data. - AS9100 or Equivalent QMS
Aerospace buyers expect a certified quality system to be in place. It ensures that controls, risk management, and nonconformance tracking are up to industry standards.
Documentation Standards and Quality Control
Documentation is not an afterthought—it’s part of the deliverable. Aerospace buyers expect full inspection reports, material certificates, process documentation, and proof of compliance with all drawing notes.
Key Documentation Requirements:
- First Article Inspection (FAI) per AS9102
- Material Certificates with traceable batch and heat numbers
- Process Certifications (anodizing, painting, plating, etc.)
- Dimensional Inspection Reports with recorded measurements
- Shipping and Handling Records for transit condition control
Quality assurance must be built into the process—not just added at the end. That means in-process inspection, final part validation, and strict adherence to the quality plan agreed upon with the customer.
Tooling, Fixtures, and Setup Validation
Though the design is provided, suppliers often need to develop tooling and fixtures to hold, cut, or assemble components. These tools must:
- Match the drawing geometry with no deformation or bias
- Hold the part securely for repeatable machining
- Allow for proper inspection access
- Be validated before use and re-qualified periodically
Tooling mistakes lead to dimensional drift and failed inspections, which are costly and delay deliveries. Every setup change must be documented, and changes to process flow require formal approval.
CNC Machining and Programming Accuracy
Aerospace components demand tight tolerances—often ±0.001 inch or less. This means:
- CNC programs must be simulated before being run
- Machines must be calibrated regularly
- Tool wear must be monitored and offset data recorded
- Any deviation must be recorded and evaluated
Parts are often machined from expensive materials like titanium or Inconel, which require slower speeds, high tool quality, and coolant systems designed for heat management.
Cleanroom and Handling Requirements
Contamination is a serious issue in aerospace—foreign object debris (FOD) can compromise performance and safety. Suppliers must have strict handling controls:
- Dedicated clean areas for inspection and assembly
- Use of gloves, lint-free materials, and protective packaging
- Cleanroom protocols where sensitive electronics or optics are involved
Even fingerprint oils on mating surfaces can impact assembly integrity or cause corrosion over time, so suppliers are expected to adhere to cleanliness specifications at every stage.
Shipping, Packaging, and Labeling Compliance
Once the part passes inspection, the job is not yet done. Aerospace shipments require:
- Anti-static or moisture-barrier packaging as applicable
- Custom foam inserts or fixtures for protection
- Lot traceability on labels and shipping documents
- Compliance with ITAR or EAR regulations when applicable
Failure to package correctly can lead to parts being rejected on arrival, even if they passed inspection at the supplier’s facility.
Supplier Approval and Audit Readiness
To become and remain an aerospace supplier, companies must:
- Pass initial supplier audits from the customer
- Maintain and demonstrate process capability through periodic audits
- Respond to corrective actions and continuous improvement programs
- Provide objective evidence of compliance to all flow-down requirements
Being audit-ready is part of the aerospace culture. It’s not just about having a good part—it’s about proving, consistently, that your systems can produce it every time.
Common Challenges in Build to Print Execution
Even experienced vendors face challenges when working under a build to print contract. Common issues include:
- Misinterpretation of complex tolerances
- Use of non-approved alternate materials
- Missing or incomplete documentation
- Dimensional drift due to worn tooling
- Delays caused by special process outsourcing
These challenges are manageable, but only if addressed proactively through training, internal auditing, and quality planning.
Integration with Aerospace Supply Chain Portals
Many aerospace primes and Tier 1s now use digital supplier portals for RFQs, order tracking, document submission, and compliance checks. Suppliers are expected to:
- Upload inspection and process reports
- Acknowledge purchase orders and shipping milestones
- Communicate NCRs and corrective actions
- Maintain real-time status updates
This level of integration ensures traceability and improves turnaround times, but it requires discipline and digital readiness on the supplier’s side.
Final Thoughts
Success in aerospace supply chains isn’t just about delivering a quality part—it’s about delivering exactly what the buyer asked for, fully documented, traceable, and packaged to spec. built to print manufacturing leaves no room for interpretation or shortcuts. It’s a disciplined process that demands accuracy, compliance, and a deep respect for the engineering intent embedded in every drawing. Suppliers who master this model position themselves for long-term, high-value contracts in one of the most demanding sectors on Earth.
