In industries where safety and reliability cannot be compromised, nondestructive testing (NDT) has become an essential tool. Unlike destructive methods, which damage or consume a part to test its limits, NDT allows components to be inspected for flaws without harming their integrity.
What Is Nondestructive Testing?
NDT is a set of inspection techniques that identify cracks, corrosion, porosity, or other defects in metals and materials. Because the process leaves the part intact, it’s ideal for industries where components are expensive, highly engineered, or safety-critical—such as aerospace, defense, automotive, and heavy equipment manufacturing.
Common NDT Methods
- Liquid Penetrant Inspection (LPI): Detects surface cracks with visible or fluorescent dyes.
- Magnetic Particle Inspection (MPI): Reveals surface and near-surface flaws in ferrous metals.
- Ultrasonic Testing (UT): Uses sound waves to detect internal flaws or measure thickness.
- Radiographic Testing (RT): X-ray or gamma inspection for internal weld or casting defects.
Each method provides unique insights into part quality, ensuring defects don’t go unnoticed.
Key Benefits of NDT
- No Damage: The part being tested remains usable.
- Improved Safety: Flaws are detected before they can cause failures.
- Cost Savings: Reduces scrap, rework, and warranty issues.
- Compliance: Meets strict standards like NADCAP and MIL-SPEC.
NDT in Aerospace & Defense
For aerospace and defense manufacturers, NDT is more than a best practice—it’s a requirement. Components must perform under extreme stress and environmental conditions, and even the smallest flaw can have serious consequences. NADCAP-certified NDT ensures reliability, safety, and compliance with industry regulations.
Sub Source: Your Partner in NDT Services
At Sub Source Inc., we provide a full range of nondestructive testing services, including LPI, MPI, ultrasonic, and visual inspections. With NADCAP-certified processes and a commitment to precision, we help OEMs and manufacturers deliver safe, compliant, and reliable products.
📞 Contact Sub Source today to learn more about our NDT capabilities or to request a quote for your next project.
Types of Nondestructive Testing Used in Manufacturing
There are several NDT methods used across aerospace, automotive, defense and general manufacturing. The two most common surface and near-surface inspection methods — and the ones Sub Source, Inc. specializes in — are Magnetic Particle Inspection (MPI) and Liquid Penetrant Inspection (LPI).
Magnetic Particle Inspection (MPI)
MPI is used to detect surface and near-surface discontinuities in ferromagnetic materials such as steel and iron. The part is magnetized and then fine iron particles (wet or dry) are applied to the surface. If a crack or flaw is present, it disrupts the magnetic field and causes the particles to cluster visibly at the defect location. MPI is fast, sensitive and reliable for detecting cracks, seams, laps and inclusions in ferrous parts.
Liquid Penetrant Inspection (LPI)
LPI — also called dye penetrant inspection (DPI) — uses a colored or fluorescent liquid that is applied to the surface of a part and drawn into surface-breaking defects by capillary action. After a dwell time, the excess penetrant is removed and a developer is applied that draws the penetrant back out of any defects, making them visible under UV or white light. LPI works on metals, ceramics, plastics and other non-porous materials, making it more versatile than MPI for non-ferrous applications.
NADCAP-Accredited NDT at Sub Source, Inc.
Sub Source, Inc. holds NADCAP accreditation for nondestructive testing, which is required by most aerospace prime contractors and many defense programs. NADCAP NDT accreditation demonstrates that our processes, personnel qualifications, equipment calibration and quality records meet the rigorous requirements of the aerospace industry’s most demanding customer base. Our Level II and Level III certified inspectors perform MPI and LPI to applicable AMS, ASTM, MIL-spec and customer-specific procedures.
NDT Services in Rockford, IL
Sub Source provides NADCAP-accredited MPI and LPI nondestructive testing services in Rockford, IL. We support aerospace, automotive, defense and industrial manufacturers with fast turnaround and thorough quality documentation. Contact us to discuss your NDT requirements or to request a quote for magnetic particle or liquid penetrant inspection services.
