Test Services and Conformal Coating

The Challenge: 

Get working prototypes on the lab bench ASAP to validate the product and begin testing features, including EMI compatibility and extreme environments that require conformal coating.

The NPI Solution:

NPI’s quality objective of 98% yield is a testament to our obsession with quality inspection and testing throughout the PCB design, fab, and assembly process. With the latest AOI and fly prob services, we insure one of the industry’s highest yields on first run builds.

We understand if you add conformal coating before testing, you may face the tedious task of removing the coating, then reapplying it. This wastes time, money, and energy. It is especially bad if you have a time-to-market deadline.

At NPI Services, Inc., we recommend one of the above test services prior to conformal coating and box build system integration.


Test Services

Our test services technicians are troubleshooting experts. Whether they test a prototype or production build, a rework or modification, they seek out problems and solve them to ensure products perform to their functional specifications. This may entail basic functional testing, power-testing, flying probe or perhaps post-assembly EMI analysis.

Bottom line: When we ship the tested final product, you have the peace of mind in knowing it works.

NPI PCBA Diagnostic and Test Equipment:

  • Tektronix (MDO4104-6) Mixed Domain Oscilloscope/Spectrum and Logic Analyzer
  • Tektronix (FCA3020) Timer/Counter/Analyzer
  • Tektronix (DMM4050) 6 ½ Digit Precision Multimeter
  • Tektronix (PWS4205, PWS4602) Programmable DC Power Supplies
  • Tektronix (AFG3251) Single Channel Arbitrary/Function Generator
  • Hubbell (HD100) Hi-Pot Tester

NPI PCBA Test Services

  • Basic functional test: Customer supplied test procedure/script. NPI will verify and document product performance under controlled test input conditions
  • Power-up Test: Validate PCB design integrity to ensure no opens/shorts exist
  • Troubleshoot PCB layout: If issues exist, “ohm out” PCB with power applied
  • PCB failure analysis: Utilizing customer-supplied schematics and assembly drawings, NPI will perform “top level” circuit design testing to determine failure mode
  • Flying probe test:  FICT (fixtureless in-circuit test)
  • EMI compatibility testing for wireless devices to ISO/IEC 17025 compliance

Environmental and Analytical Test Services

In certain markets your products are expected to work in difficult environments. For example, Mil-Aero manufacturers and the defense industry as a whole demand product reliability under adverse conditions. Penetrating global markets like the European Union require RoHS (restriction of hazardous substances) compliance with environmental electronics waste and corporate social responsibility initiatives.

NPI Services, Inc.’s environmental and analytical testing focuses on reliability assessment and chemical testing. The test services below can improve your products’ reliability and help solve process and field failures.

Reliability and assessment test services

  • EMI Compatibility Testing
  • 3- axis random vibration
  • Thermal cycling/thermal shock
  • Temp/humidity
  • Heat soak/burn-in
  • Drop/shock testing up to 6,000Gs
  • Single axis sine, swept sine and shock testing

Chemical test services

  • C – Ion Chromatography
  • FTIR – Fourier Transform Infrared
  • XRF – X-ray Fluorescent Microscope
  • SEM/EDS – Energy Dispersive Spectrometer on Electron Microscope
  • HPLC – High Performance Liquid Chromatography
  • GCMS – Gas Chromatography with Mass Spectrometer
  • ICP – Inductively Coupled Plasma Optical Emission Spectrometer
  • WEEE/RoHS compliance testing, lead and hazardous materials testing


Conformal Coating Services

Some companies may offer a “one size fits all” coating solution. We don’t.

Our specialists determine your needs on a case-by-case basis, then recommend the correct conformal coating to ensure the right solution to meet design goals and the assembly’s specific requirements, including:

  • Compatibility with all components on the PCBA or PCB being coated.
  • Reliability and durability for extended product life.
  • Cost effective, reworkable protection.

The process for maximizing case-specific adaptability includes:

  1. Visually inspecting each assembly.
  2. Thoroughly cleaning assemblies that don’t meet surface cleanliness specifications.
  3. Meticulously cleaning each PCB using custom plasma processes to ensure the conformal coating is uniform.
  4. Expertly applying and curing the coating.
  5. Rigorously inspecting each coated assembly to ensure quality.

Types of Conformal Coatings

Our conformal coating specialists can apply the following materials

  • Type AR (Acrylic)
  • Type ER (Epoxy)
  • Type SR (Silicone)
  • Type UR (Polyurethane)
  • Type XY (Parylene)

Parylene Coating Services

Parylene furnishes significant advantages over web-process or dip-process conformal coating for certain applications in medical, military, aerospace, electronics, automotive and other industries. These advantages include:

  • A thinner film that thoroughly coats assemblies without increasing their size.
  • Extremely high chemical resistance and electrical properties adaptable for almost any project.
  • A vapor deposition process to ensure coatings offer uniform thickness that are pinhole free.
  • Complete conformity to ensure no area is open to exposure.

Medical applications

We supply the two most commonly used parylene coatings with specific advantages for medical applications—parylene C and parylene N.

  • They are the only conformal coating material that can be safely implanted in the human body.
  • They are biocompatible, with a long-tested history and no risk of complications.
  • They are one of the few materials approved for FDA Class 6 specifications.


Contact NPI Services, Inc. to discuss your Testing and Conformal Coating Services needs.

Each and every assembly to be coated is visually inspected, and, if needed, assemblies that do not meet specifications for surface cleanliness are thoroughly cleaned. Custom plasma processes are used to clean the boards so that each PCB conformal coating will be uniform. After the coating has been applied and has cured, each coated assembly is rigorously inspected to ensure quality.

NPI offers a variety of Parylene (polyparaxylylene) coating services. Parylene coating offers many advantages over wet-process or dip-process conformal coating for certain applications in the medical, military, electronics, aerospace and automotive industries among others. Parylene coating delivers a much thinner film than other coating processes, allowing assemblies to be thoroughly coated without increasing their size. Parylene coating offers extremely high chemical resistance and superior electrical properties that make it adaptable for nearly any project. The vapor deposition process that is utilized, allows parylene coatings to be uniform in thickness and completely pinhole free. Parylene coating services ensure complete conformity, coating the entire assembly and leaving no areas open to exposure.


In medical applications, parylene is ideal because it is the only conformal coating material that can be safely implanted in the human body. Parylene is biocompatible, with a long-tested history and no risk of complications. Parylene is one of few materials approved for FDA Class 6 specifications. NPI offers coating services using both parylene C and parylene N, the most commonly used parylene coatings for medical applications.