Tag Archive | IPC-A-610 standards

What is the maximum height of components on the PCBs for a standard Conformal Coating AOI system?

This can be critical so important to know due to the length of the machine required and the imaging technology used in the conformal coating AOI.

Camera slightly to the side. Hidden areas behind the components are now shown clearly.

Camera slightly to the side. Hidden areas behind the components are now shown clearly.

The first question to ask is are the PCBs 3D in nature or are very flat? This helps determine whether we use camera or parallax free scanning technology?

Parallax is defined as a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.

How this relates to conformal coating AOI is that with a fixed camera or a standard scanner the camera is at a fixed point and the circuit board with its 3D components may have “shadows” where the camera cannot see down the side of the components. This can be seen in the two photos below.

Take a look at our Conformal coating AOI Parallax link here to understand the issues more.

Click For further information on Conformal Coating AOI Systems from SCH Technologies.

Or, contact us here at +44 1226 249019 or email sales@schservices.com



What standards can the SCH Technologies Conformal Coating AOI systems inspect to?

The systems have a variety of software options right up to inspecting TRUE IPC Class III standards. The reason we state true standards is that most people are not inspecting to this level even though they think they are. This is due to two reasons:

  1. It is very difficult to inspect to IPC Class III standards as it is under magnification, is time-consuming and challenging for operators.
  2. Also, it is very difficult generally for customers to produce conformal coating finish to this level without creating lots of defects.

The key to all inspection, manual or automatic, is to decide what you are looking for.

The surface energy of the substrate is lower than the conformal coating

The surface energy of the substrate is lower than the conformal coating

So, what type of conformal coating defects are you looking for? Are you looking for bubbles?Are you looking for foreign bodies? Or is it just coating in the right place and coating not in connectors? These questions are related to the inspection criteria you desire and it is very important to define exactly what are you actually looking for.


The software we use can measure all of these factors. The key is to understand whether your production process can stand up to the level of inspection/interrogation that the machine will provide?

Click For further information on Conformal Coating AOI Systems from SCH Technologies.

Or, contact us here at +44 1226 249019 or email sales@schservices.com

What is UL 746E and what does this mean for conformal coating?

Underwriters Laboratory (UL) are a global safety certification body for consumer electronics.

UL 746E measures the ignition resistance of the conformal coating to electrical ignition sources. The conformal coating material’s resistance to ignition and surface tracking characteristics is described in UL 746E.

If you would like to know more about conformal coating standards and handbooks or other products and services offered and supported by SCH Technologies, please do not hesitate to contact us

Telephone: +44 1226 249019

Email: sales@schservices.com

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Why do I need a Conformal Coating AOI system? My robot application process is fully automated

Anyone who uses a selective robot system for applying conformal coating knows that the system can go wrong. The robot dispenses a liquid. This automatically introduces variables that can go wrong in a variety of ways including

  • The coating drying out in the valve leading to a blockage or misdirected coating onto the board
  • The material running out and not enough deposited
  • The PCB put in the wrong way or the wrong PCB for the program put in the machine
  • A component out of alignment leading to a collision of the valve with the board
  • The wrong viscosity put in the machine or the viscosity changing with temperature
  • The material curing in the machine causing a blockage

It is possible to engineer many of these problems out with options purchased at the time for the selective robot. But, ultimately, no manufacturer of material or equipment will guarantee no problems with their process. So, a conformal coating inspector is needed to check the quality of the process.

Yet, why is this the last part of the coating line that is generally not automated. The rest of the line is and the majority of an assembly line is. But, in conformal coating the general industry still relies on an operator visually inspecting a circuit board by eye under UV light. However, it is well known that operator fatigue leads to errors in inspection. Therefore, PCBs that are coated incorrectly will get past the inspectors.

Hence, an Automated Conformal Coating Inspection System  can be used to remove the operator error in the line and improve the process.

Inspecting Conformal Coating on PCBs – Using the IB100 Conformal Coating Inspection Booth

The IB100 conformal coating inspection booth is an ideal work station for operators to inspect & finish circuit boards which have been conformal coated.

Fitted with dual UVA lamps behind a safety screen to allow solvents to be used safely in the booth, the IB100 offers 36W of ultraviolet light for maximum visual inspection & finishing performance without compromise to operator safety in operation.

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Conformal coating Inspection – A range of systems for inspecting conformal coatings on PCBs

SCH Technologies design and manufacture a range of purpose-built, compact and coordinated UV inspection & finishing booths for conformal coating inspection.

These systems are used in SCH’s coating service and have been optimised to offer the best inspection & finishing performance without compromise to health & safety, coupled with ergonomic design to minimise operator fatigue.

An important point in conformal coating inspection & finishing is to creat the optimum environment where an opertor can easily inspect coated circuit boards without fatigue to body or eyes, provide the highest quality results for the conformal coating process and keep the operator safe from the harmful effects of solvents.

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Conformal Coating Training Room – For conformal coating training

SCH offer quality conformal coating training both on and off site.

Dedicated Conformal Coating Training Room

SCH have a dedicated training room for conformal coating courses and demonstrations of conformal coating equipment.

Using this facility candidates get complete hands-on experience with the conformal coating systems and processes without disturbance to production with a full range of systems available to ensure the best learning environment.

Conformal coating systems in the training facility include UV conformal coating curing, conformal coating dip, conformal coating spraying, manual conformal coating inspection and the new ACCIS Automated Conformal Coating Inspection System. Further, processes such as viscosity measurement, masking, de-masking, coating thickness measurement and solvent exposure monitoring can all be undertaken to give the maximum experience to the candidate.

Whether you plan to install a conformal coating process or currently use conformal coatings such as Humiseal we can help to develop or optimise your conformal coating process, to ensure you achieve the best performance. SCH can offer expert training in all areas of conformal coating including conformal coating application techniques, conformal coating material selection, optimisation, conformal coating health & safety and trouble shooting conformal coating problems.

Click here for conformal coating training page.