Daniel,
I suggest one of the first things you try is switching over to metal
squeegee blades. It sounds like you're getting a lot of "scavenging" from
the rubber squeegee blades (where the blade is conforming down into the
stencil aperture and scooping paste out).
From personal experience I would recommend "Permalex" metal blades.
Regards,
Martin
===== Original Message from [log in to unmask] (TechNet E-Mail Forum.) at
3/10/00 13:13
>Hi Technetters,
>
>We are now starting the fine pitch printing (20 mils pitch). Previously,
>the smallest pitch size is 25 mils. However, we encountered paste printing
>problem.
>
>We do not have problem with the paste deposition on the pads which parallel
>to the squeegee flow direction. However, we found insufficient solder
>paste on those pads which are perpendicular to the squeegee flow direction.
>
>We are using a semi-auto screen printer with rubber squeegee (durometer
>#90). Stencil thickness is 5 mils.
>
>May I know the remedy action for such process problem?
>
>Many thanks in advance
>
>Best regards,
>
>WW Woon
>email: [log in to unmask]
>
>
>
>Daniel Woon
>Assistant Manager, PCBA Department
>Comacraft Sdn Bhd (A Subsidiary of Dynavest Group-Asia)
>2033, Jalan Bukit Minyak,
>Kawasan Industri Ringan Asas Jaya,
>14100 Bukit Mertajam,
>Penang, Malaysia.
>Tel : 60-4-5889933
>Fax : 60-4-5889953
>H/P : 60-19-4706083
>Email : [log in to unmask]
>Website: http://www.dynavest.com.sg
>
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Best regards,
Martin Christie
Process Engineer
ACW Technology Ltd.,
Hylton Road,
Petersfield,
Hants.
GU32 3XX
Tel: 01730 300000 ext 146
Fax: 01730 266045
e-mail: [log in to unmask]
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