Best Conformal Coating Method to use for Low Volume Production

ANDA AUTOMATIONhttp://www.anda-automation.com

W h at i s t h e B e s t W h at i s t h e B e s t C o n fo r m i n g M e t h o dC o n fo r m i n g M e t h o d

t o u s e fo r t o u s e fo r l o w vo l u m e l o w vo l u m e p ro d u c t i o n ?p ro d u c t i o n ?

Anda AutomationAnda Automation

Presented byPresented by


Conformal CoatingConformal Coating

Conformal coatings are very thin dielectric coatings to protect the surface of a printed circuit board (PCB).



An operator applies layers of coating onto the PCB to protect the substrate and circuitry from the elements that could harm them.



Conformal coating acts to extend the longevity of the PCB and shields the board from corrosion and mechanical damage.


Loctite 3900 Aerosol CoatingLoctite 3900 Aerosol Coating

One of the simplest One of the simplest methods of conformal methods of conformal coating for PCB coating for PCB assemblies involves the assemblies involves the use of LOCTITE 3900. use of LOCTITE 3900.

It is an air-dry coating It is an air-dry coating material that is designed material that is designed specifically for small specifically for small volume runs. volume runs.



It can be applied to the It can be applied to the PCB by dip or spray PCB by dip or spray method, and you don’t method, and you don’t have to invest in any have to invest in any coating equipment other coating equipment other than what is necessary to than what is necessary to remove coating and keep remove coating and keep operators safe from operators safe from inhaling the fumes from inhaling the fumes from the material. the material.



When you apply to the When you apply to the PCB, the coating is PCB, the coating is applied by precision spray applied by precision spray from an aerosol can. from an aerosol can.

After the material is After the material is sprayed on the PCB, it will sprayed on the PCB, it will air dry tack-free in about air dry tack-free in about five minutes. five minutes.



The coverage applied The coverage applied provides a durable and provides a durable and solvent-resistant shield solvent-resistant shield with a high dielectric with a high dielectric strength. strength.



LOCTITE 3900 is used in LOCTITE 3900 is used in applications with an applications with an optimal temperature range optimal temperature range of -40 °Celsius to +125 of -40 °Celsius to +125 °Celsius. °Celsius.

Although it is an aerosol Although it is an aerosol spray, it contains no spray, it contains no chlorofluorocarbons or chlorofluorocarbons or chlorinated solvents. chlorinated solvents.



Here are the directions for Here are the directions for conformal coating printed conformal coating printed circuit boards with the spray circuit boards with the spray method:method:



1. Clean all surface 1. Clean all surface contaminants from contaminants from PCB--material such as PCB--material such as grease, silicon, and grease, silicon, and ionic residues can ionic residues can cause adhesion issues cause adhesion issues and wicking.and wicking.



2. Mask board keep out 2. Mask board keep out areas of the PCB as areas of the PCB as required. required.

3. Shake the aerosol can 3. Shake the aerosol can thoroughly before thoroughly before using.using.



4. Use an even motion to 4. Use an even motion to spray the PCB from spray the PCB from approximately 6 to 8 approximately 6 to 8 inches from the inches from the surface. Spray at about surface. Spray at about a 45° angle.a 45° angle.



5. Rotate the PCB and 5. Rotate the PCB and then repeat the then repeat the application 2-3 times to application 2-3 times to get the best coverage.get the best coverage.

6. Apply the spray to the 6. Apply the spray to the PCB in a horizontal PCB in a horizontal position to get an even position to get an even amount of coating.amount of coating.



7. A coating of 0.002 7. A coating of 0.002 inches to 0.003 inches inches to 0.003 inches (0.05 to 0.07 mm) will (0.05 to 0.07 mm) will dry tack-free within 5 dry tack-free within 5 minutes at 22 °Celsius minutes at 22 °Celsius and 40 to 60 % relative and 40 to 60 % relative humidity.humidity.

8. The PCB should air 8. The PCB should air dry for 24 hours at 22 dry for 24 hours at 22 °C to get a full cure °C to get a full cure effect.effect.


Dip CoatingDip Coating

Dip coating works extremely Dip coating works extremely well in applications where well in applications where most of the areas that are most of the areas that are not to be coated are on the not to be coated are on the same edge of the assembly.same edge of the assembly.



You can then dip up to You can then dip up to these keep out areas and these keep out areas and eliminate much of the eliminate much of the masking that is required.masking that is required.



One conformal coating type One conformal coating type that is good for dip coating that is good for dip coating applications is HumiSeal applications is HumiSeal 1B31 Acrylic Conformal 1B31 Acrylic Conformal CoatingCoating

Like Loctite 3900, it can also Like Loctite 3900, it can also be used for both spraying or be used for both spraying or dipping PCBs. dipping PCBs.



Any components that are Any components that are not supposed to be not supposed to be coated must be masked in coated must be masked in the dipping process; the dipping process; otherwise the immersion otherwise the immersion of the PCB into the of the PCB into the coating will get into the coating will get into the keep out area and require keep out area and require extensive repair. extensive repair.



The area should be The area should be thoroughly taped or thoroughly taped or masked with liquid latex masked with liquid latex materials or rubber materials or rubber masking boots to keep the masking boots to keep the coating out of these coating out of these sensitive areas.sensitive areas.



Dip coating is a time-Dip coating is a time-consuming process for consuming process for conformal coating PCB conformal coating PCB assemblies, and if done assemblies, and if done improperly will cause a improperly will cause a significant amount of significant amount of rework. rework.



When dipping by hand, it is When dipping by hand, it is best to add up to 50% of best to add up to 50% of thinning material to reduce thinning material to reduce the viscosity of the material the viscosity of the material to the level it is needed. to the level it is needed.

The immersion rate to dip The immersion rate to dip the boards is determined by the boards is determined by the population density of the the population density of the PCB that is being dipped. PCB that is being dipped.



If your facilities have If your facilities have medium scale throughput, it medium scale throughput, it will probably be a better idea will probably be a better idea to invest in spray gun to invest in spray gun equipment and other equipment and other supporting equipment supporting equipment needed. needed.


Conformal Coating MachineConformal Coating Machine

For high volume shops, For high volume shops, such as those that service such as those that service the auto industry, it is the auto industry, it is usually better to invest in a usually better to invest in a conformal coating machine.conformal coating machine.


Conformal Coating MachinesConformal Coating Machines

Conformal coating machines Conformal coating machines handle a higher volume handle a higher volume excellently, and its excellently, and its throughput justifies the throughput justifies the expenditure on equipment, expenditure on equipment, labor, and special material. labor, and special material.


Brought to you byBrought to you by

Anda AutomationAnda Automation

anda-automation.comanda-automation.com

Best Conformal Coating Method to use for Low Volume Production

Engineering

Transcript of Best Conformal Coating Method to use for Low Volume Production