Tag Archive | process

Five Reasons Why Conformal Coating Dipping can be One of the Most Effective Production Processes

Dipping a circuit board in coating can be highly effective. Here are five reasons why:

  1. You can dip many boards at once. It can be the fastest conformal coating process of all the methods.
  2. It is an extremely simple process. Hang the circuits, press a button and the boards are coated.
  3. The process is very repeatable. Once set up the conformal coating thickness will be constant with very few process controls.
  4. The conformal coating penetrates underneath components. This gives complete coverage.
  5. The boards are coated both sides simultaneously. This halves the process time.

For further information click conformal coating dipping

Or contact us now at Sch technologies. Conformal Coating made simple….

How to Select a Conformal Coating Process – The Holistic Approach

Choosing a conformal coating process is a complicated and involved process usually balancing a number of trade-offs and compromises.

This is because of three major parts of the complete process that can offer different options and create difficult choices.

These parts are:

  1. The Conformal Coating Material Requirements
  2. The Application Method Selected
  3. The Circuit Board Design

When you consider these three points you have to balance them to create the best compromise solution that suits your requirements.

This is the Holistic Approach to conformal coating.

Find out more by click Nexus Ebook: How to Select a Conformal Coating Process

What is capillary flow in conformal coating and why does it occur?

Capillary / Scavenging on a printed circuit board where the coating has run away from an area around a component.

Capillary / Scavenging on a printed circuit board where the coating has run away from an area around a component.

Capillary flow (also known as scavenging) in conformal coating is where the conformal coating pulls or runs away from certain areas of a PCB to more favourable sectors due to a combination of effects. This can leave a patchy finish on the surface of the board.

Factors that influence the capillary effect during processing include:

  1. low viscosity of the conformal coating
  2. an abnormally high amount of coating applied
  3. a low surface energy of substrate
  4. the high surface tension of the conformal coating.

For further information Click capillary conformal coating failure mechanism technical bulletin

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How to verify the conformal coating thickness on a printed circuit board in production for a dip coating system

When using a conformal coating dipping system it is important to know that the dry film conformal coating thickness is correct on the circuit board. Ultimately, the conformal coating will only be protective if applied at the right thickness so control of the process is crucial.

First, when we are coating PCBs we must assume that the variables for the conformal coating dip coating process are set up correct for the PCB. That is that

  1. The viscosity of the conformal coating is correct
  2. The withdrawal speed of the dip system is correct
  3. The temperature of the conformal coating is stable

These three parameters ultimately control the final thickness of the conformal coating on the circuit. Change one of the these and you can change significantly the conformal coating thickness.

Once this is set up and everything is in order we now want to monitor the coating thickness.

There are two options:

Positester conformal coating thickness measurement system roundedOption one: Measure the circuit board directly.

This can be done with a micrometer or a conformal coating eddy current system such as  a Positector. However, this assumes that there is enough room for the probe or micrometer on the circuit board and (ii) there is metal in the PCB at the point of measurement for the Positector. Using this system after the coating is cured hard enough to test gives excellent readings

If this is not the case there is an alternative solution.

Option 2: Measure a test coupon

If the conformal coating thickness is correct on a circuit board when qualifying the process then it is possible to dip a test coupon to measure the equivalent coating thickness. This then allows you to use a test coupon at the start of the day’s production process to confirm everything is in order and no parameters have changed.

The process is the same as with measuring the circuit board. Dip the coupon. Dry it sufficient to measure the coating thickness and verify that the process is stable and there is no significant variation.

This is an easy method that is reliable. It also backs up your viscosity control measurements for your conformal coating and ensures your conformal coating dip process is in control.

Click Conformal Coating Thickness Measurement for further information.

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

 

 

Can you use a moisture cure silicone conformal coating in a dipping machine?

Conformal Coating Dip System with PCBs hung ready to be coated

Conformal Coating Dip System with PCBs hung ready to be coated

The answer is yes. It is done regularly and we have dip coating systems filled with moisture sensitive silicone materials that function perfectly.

The key is the way the conformal coating and the process is set up. Follow these steps to ensure your silicone dip conformal coating process is successful.

  1. The coating may skin on the surface. Remove this whenever it occurs.
  2. Use a catch tray in the weir of the dip tank. When the congealed coating drops into the catch tray the lumps will be caught.
  3. Apply a moisture free gas across the surface of the tank. This inhibits the moisture in air prematurely curing the coating.
  4. Minimise the pumping of the coating. Turn the speed down to a minimum and only pump the coating when in use. turn off the pump there are long periods of no coating.
  5. Apply proprietary thinners over the top of the coating during long periods of shut down

Contact us now to discuss your conformal coating dipping process and how we can help you.

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

Want to reduce your outsourcing costs of your conformal coating process or check just what it will cost to subcontract?

Conformal Coating PCB inspected in IB101 Inspection Booth 2Conformal Coating Services FREE TRIAL

We guarantee to offer the lowest price solutions on a like for like basis for our subcontract coating services through our North America, Europe and Asia facilities.

How can we say guarantee this?

  • We are experts in what we do! that means you get the best prices
  • We provide conformal coating services at source to the customer where we can
  • This means we benefit from lower costs in our facilities which we can pass on as savings
  • We have the full range of conformal coating processes and materials to offer so the customer gets the right application method and not a process which is isn’t fit for purpose.

This helps SCH provide the lowest cost solution without compromise to the customer.

FREE TRIAL

Let us prove to you we can coat your printed circuit boards and save you money.

Click here for your FREE TRIAL of Conformal Coating Services

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Links of Interest

Conformal Coating Parylene Services

Why Use Parylene?

Parylene Equipment

Parylene Removal

Global Subcontract Conformal Coating Services

SCH Technologies provide Global subcontract liquid Conformal Coating and Parylene Coating Service Solutions across North America, Europe and Asia.

We are the number one complete conformal coating solution supplier within these markets. Our aim is provide the same level of conformal coating service for application of all types of coatings wherever the customer is in the world without compromise.

This allows our group to work with customers to offer the best level of service when qualifying or coating products without concern about where the printed circuit boards (PCBs) may eventually finish up being manufactured.

In short

  • We are conformal coating solution providers in North America, Europe and Asia.
  • We apply Parylene, Conformal Coating and RFI Shielding Paints using all manner of the standard methods
  • We aim to provide the same level of service wherever we process your circuit boards in the world

Check out our conformal coating and parylene service pages here.

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