Tag Archive | conformal coating inspection

Come and see our Conformal Coating Automated Optical Inspection (CCAOI) systems demonstrated at Electronica in Bangalore and make your conformal coating inspection process reliable

Conformal Coating Automated Inspection System

Conformal Coating Automated Inspection System

SCH Technologies are working as a partner with German company, Modus, to provide a range of  Automated Conformal Coating Inspection Systems (CCAOI).

These modular systems provide optimised UV inspection of conformal coatings and defect detection on a printed circuit board production line.

The success of the design lies in integrating Modus’s state of the art software and lighting system with SCH’s equipment designs.

This partnership provides modular  inline and batch solutions which are elegant, flexible, cost-effective and efficient Conformal Coating Inspection Systems.


 

Why use automated inspection in Conformal Coating?

Conformal Coating defects like bubbles can be detected using UV Automated Inspection Systems like CCAOI

Conformal Coating defects like bubbles can be detected using UV Automated Inspection Systems

Conformal Coating Inspection is a critical and often neglected stage of the conformal coating process.

The standards such as IPC A 610 are explicit in their requirements for conformal coating inspection yet few companies actually inspect to that level.

The reality is most operators cannot meet these stringent requirements on a repeated basis and therefore automating the process is the logical next stage. 


Do you want to improve your conformal coating inspection process and get a viable return on your investment?

If the answer is yes then come and talk to us at our STAND 3125 at Electronica Bangalore and see how you can save money and improve your process.

Or contact us

UK:

Tel: +44 1226 249019

Email: sales@schservices.com.

India:

Technical Manager: Madhusudan Marepalli

Email: madhusudan.m@schservices.com

Ph1: +91-889 707 6489
Ph2: +91-880 137 9949

 

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

 

 

How do I avoid Parallax in my conformal coating inspection process?

To achieve parallax free processing you have to use a specialist lens which removes the parallax issues from the scanning process and eliminates shadows down the sides of high components.

Fixed camera solutions or scanners with a fixed camera system at the centre can suffer from parallax where high sided components can cause shadows in image processing.

Modus have made unique technological advances in parallax-free image capturing for conformal coating processing. They use a specialist lens on their scanner based system that adjusts the lens focus so the image appears to be viewed from above at all points along the scan.

In conformal Coating AOI Fixed camera solutions or scanners with a fixed camera system at the centre can suffer from parallax

In conformal Coating AOI Fixed camera solutions or scanners with a fixed camera system at the centre can suffer from parallax

Click Automated Conformal Coating Inspection System for further information on the Modus system.

What is parallax and why is this important in my inspection of conformal coated circuit boards?

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.

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.

Camera directly above image with the image showing all detail down the side of the components

Camera directly above image with the image showing all detail down the side of the components

 

 

 

 

 

 

 

In figure 1 some components are obscured by others since the camera is not vertically above the board. In figure 2 the image shows the components directly from above and no components are hidden by others.

Click Automated Conformal Coating Inspection System for further information on how to avoid parallax.

What is a Conformal Coating Automated Optical Inspection (AOI) System?

An AOI system for inspecting conformal coated circuit board is there to replace a manual operator who physically has to sit and inspect every single board at the end of a line.

Conformal Coating Inspection is a critical and often neglected stage of the conformal coating process. It is the last area of the assembly line that is 95% manually operated around the world yet it is one of the most critical factors.

There have been several challenges to be met in AOI for inspecting conformal coating. The fact that the coating is transparent so everything under the coating can be seen , the coating fluoresces under UV light and the PCBs are 3 dimensional means that the process offers a lot of challenges.

Click Conformal Coating Automated Optical Inspection (AOI) System to find out more.

How do I measure the thickness of a conformal coating on a Printed Circuit Board?

Positect 6000 Thickness Test System

Positest 6000 Thickness Test System cure and measure the test coupon again at the same point. The difference gives you the coating thickness.

The low cost method is using a calibrated micrometer screw gauge that can measure down to ± 10 um. First measure a point on the board or test coupon, apply the coating,

A couple of pitfalls to avoid are ensuring the coating is cured hard enough since if it is soft it could compact and give a false reading. Also, do not measure one point. Take an average of at least 3 or 4 points since this will give a better result statistically.

Test coupons are the ideal method for measuring the coating thickness, whether is it spraying or dipping, and can be kept as a physical record of the performance.

An alternative method is using a non contact technique using eddy currents. A system like the Positest 6000 offered by SCH is extremely quick and accurate to ±1 um.

A final method is a wet film measurement technique which is very cost effective. This uses a comb with different size patterns which is placed in the wet coating and the imprint left indicates the wet film thickness. Knowing the solids content of the material means that the material

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.