Daan’s Tips & Tricks

Stencil cleaning

My name is Daan van Hoogstraten, I recently started at Partnertec as customer process support manager. I have 20 years of experience in the electronic assembly industry in both sales and service jobs. In my new role I want to help you, as our customer, to improve your production processes.

In our previous newsletter, Pieter Verheggen shared information about how to create a correct stencil printing program. Today I would like to share some tips and tricks on stencil cleaning. To achieve a good Printing result, correct handling of stencils is very important. Stencils that are damaged or dirty will have a big impact on how accurate the paste will be applied on the board. This will directly influence the
quality of the solder joints on your PCB’s.

The best stencil cleaning results is achieved using automated stencil cleaningequipment, such as MBtech N29 series. If you don’t have a machine available, you need to clean the stencils manually after each production run. I recommend to use DEK saturated stencil clean wipes. These lint-free wipes contain a special cleaning agent that easily wipes of remaining paste, without being too aggressive. Best result is achieved by simultaneously wiping the top side and bottom side; press your hands with wipes together and make circular moves
over both the surfaces.

You can clean and dry the stencil afterwards using compressed air, but you need to be careful not to damage the stencil with too high pressure. Keeping the stencil tensioned in the frame reduces this risk. If wipes and air cleaning does not sufficient clean the stencil, you could consider to clean the stencils with a manual ultrasonic cleaner, such like the GEN3 Gensonic. Stencil cleaning agent is sprayed on the stencil and the 40Hz ultrasonic head is manually moved over the surface. Even the most difficult particles stuck in corners of small apertures will be removed this way.

Don’t hesitate to contact me, if you need more recommendation or support on any of your assembly processes.

Daan van Hoogstraten