Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

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Tony A

#12084

squeegee angle | 2 April, 1999

Anyone knows what is the optimum squeegee angle for screen printers.

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Dean

#12085

Re: squeegee angle | 2 April, 1999

| Anyone knows what is the optimum squeegee angle for screen printers. | | 45 Degrees. The forward velocity creates a downward pressure equal to the vector pressure (equalibrium). This is commonly known as paste "rolling action". Too obtuse an angle causes poor roling or "plowing" (insufficient filling action). Too acute an angle causes the paste to ride up on the blade and cause poor (if any) rolling. This rolling action also mixes the paste and helps to keep the solder paste useable. Regards, Dean |

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Scott Davies

#12086

Re: squeegee angle | 6 April, 1999

Tony

Although I agree in principle with Dean that 45 Degrees would be ideal, most of the squeegees I have worked with have been 60 Degrees to the stencil surface. This seems to work best with metal squeegees when printing HASL boards, because the slightly uneven pad surface can lead to the paste "bleeding" if the printing pressure is too high (i.e. you don't get a good seal between the edge of the stencil aperture and the pad surface).

Also, check out Dek's ProFlow and MPM's RheoPump systems.

Regards Scott Davies

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Tony A

#12087

Re: squeegee angle | 7 April, 1999

| Tony | | Although I agree in principle with Dean that 45 Degrees would be ideal, most of the squeegees I have worked with have been 60 Degrees to the stencil surface. This seems to work best with metal squeegees when printing HASL boards, because the slightly uneven pad surface can lead to the paste "bleeding" if the printing pressure is too high (i.e. you don't get a good seal between the edge of the stencil aperture and the pad surface). | | Also, check out Dek's ProFlow and MPM's RheoPump systems. | | Regards | Scott Davies | Thanks for the feed-back Scott and Dean, I will be doing a DOE using these two angles.

Thanks again I will keep you posted on my results.

Tony A

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