CEM Services - UK Made - Complex Capability 

Conformal coating & selective spraying technology

Our range of capabilities extends to a full conformal coating process. We support two distinct methods, allowing us to support prototype and NPI orders through to full batch production. Sbooth Gemini Tec

Automated and selective spraying with our PVA coating system provides a accurate and repeatable coating process for production. This is complimented with our manual spray booth operation to allow smaller batch sizes to be coated in much shorter lead times. We typically use our spray booth for quantities 1 to 10 pcs, prior to tooling our automated system. 

We coat PCB assemblies using a wide variety of conformal coating products, our automated system carries HumiSeal 1B31 acrylic (qualified to MIL-I-46058C) as standard. Products can move between the various methods or be fixed to a process, to suit the specific needs of the PCBA or customer.

The benefits of selective spraying:

Robotic spraying allows fine amounts of coating to be selectively dispensed onto PCB's with high accuracy and optimum repeatability. Multi axis control allows the coating to sprayed on, around and underneath complex components. The distinct advantage of this technique means there is no longer a need to mask the keep out areas of the PCB. Selectively spraying allows a price point typically 20% to 30% lower than traditional coating methods.


The preparation of PCBA's for coating is paramount and we pre-treat and clean products to exceed the guidelines of IPC CH-65 A and J-STD 001-D prior to coating. We operate two cleaning methods, ultrasonic with vapour cleaning and aqueous cleaning. Conformance is checked with our 'Zero Ion' contamination testing system to validate the correct level of cleanliness is achieved, prior to the application of any coating materials.

PVA selective technology coating machine at Gemini Tec


  • Automated PVA Robotic and selective spraying system, with no masking requirement.
  • Spray booth for low volume prototypes/NPI orders.
  • Automated Spraying for accurate viscosity/thickness of coating and 100% repeatable process.
  • Manual spray booth for rapid delivery orders.
  • Pneumatic tilt axis for spraying underneath components.
  • Manual spray booth for rapid delivery orders.
  • Full cleaning process to meet J-STD 001-D (MIL SPEC)
  • Full cleaning process to meet IPC CH-65 A.
  • Ultrasonic with vapour cleaning and aqueous batch washing PCBA preparation.
  • Ionic testing, with 'Zero Ion' system.

PCB assembly with conformal coating applied by Gemini Tec Aqueous washing at Gemini Tec 

Gemini can provide its customers with fully coated PCB assemblies as part of its turnkey operation. Our automated & selective process can be provided at cost effective rates. Should you be considering the use of conformal coating, please contact us to discuss our capability in contract manufacturing for your PCB assemblies. Tel +44 (0) 1252 333 444