How to Calculate the Cost of Conformal Coating on a PCB?

One of the most basic and common questions we at HumiSeal^® are asked by both existing and potential new customers is,

“How much does it cost to conformally coat my printed circuit boards?”

Since conformal coatings are usually sold in liquid form by the liter or gallon, it is necessary to go through a fairly basic calculation that we will present here.

The simplest and most common way to evaluate cost is by determining the cost in dollars of coating per PCB.

Units, units, units!

Those of you familiar with engineering or scientific education are probably quite aware of the absolutely critical issue of using the proper units.

For those of other backgrounds, the term “units” is just a word for the little words that come after the numbers. When we ask how much you weigh, we expect more than just a number answer; we expect a number and a word denoting the unit of measure or units. In this case it would be pounds, kilograms, stone, or possibly others if you choose to get creative.

In order to get to the final number, we want, which is the dollars-per-board cost for conformal coating, we must choose and be consistent with our units. It is possible to do this calculation with any set of consistent units, but we have tried to choose the most common for this application.

They are as follows:

• Prices will be in decimal dollars (e.g., $60.46 would be entered as 60.46).
• Thicknesses will be in mils, which are thousandths of an inch (e.g., 1.5 mils would be entered as 1.5).
• Percentages will be entered as decimals (e.g.,13% as 0.13 and 100% as 1.0).
• Lengths will be in millimeters.
• Volumes will be entered in decimal liters.

What information do I need in order to calculate my cost?

Just like when you sit down to file your taxes each year -- and just about as enjoyable -- you will need a few key pieces of information in order to complete the calculation.

They are

• the coating price per liter (decimal dollars, so for example $40.27= 40.27),
• the solids percentage (decimal) of your coating AS APPLIED (This is usually found on the technical data sheet. If adding additional thinner, see below.),
• the dimensions (in millimeters) of the COATED AREA ONLY of your PCB,
• the conformal coating thickness dry in mils (If unsure, use 3.0), and
• the mix ratio of coating to thinner, if used.

What if I add thinner before applying my conformal coating?

Note: If you use your conformal coating exactly as it comes from the manufacturer with no additional thinning, you can skip ahead to “Finally the calculator for your cost per PCB” and start entering your numbers.

If you are adding additional thinner as a processing aid before coating, your life has just become a little bit more complicated. The use of thinner will affect both the calculated price for your coating as well as the solids percentage used in the formula.

Below is a calculator for getting the numbers you need (the numbers in green)

Finally, the calculator for your cost per PCB!

Once you have the key numbers noted above, such as solids percentage, prices, and dimensions of your board, you are finally ready to enter them into the chart and calculate a number.

As a supplier of electronics protection polymers and coatings, Chase Corporation and our employees can help you with an unbiased approach to evaluating your application and process. We’ll show you how to maximize efficiency, minimize cost, and improve product reliability. Our outstanding manufacturing and technical support groups can provide your organization with reliable global supply, unmatched quality, and superior technical support.

Please contact us today to discuss your application.