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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Squeegees for Step-Down stencil

#22500

Squeegees for Step-Down stencil | 24 November, 2002

Hello!! I have a questions about what kind of squeegee blades i need for any step-down stencil in order to get the better results in my process.

I have stencils with step-down from 10 mils to 6 mils. Thanks in advance.

reply »

#22501

Squeegees for Step-Down stencil | 24 November, 2002

Hello!! I have a question about what kind of squeegee blades i need (this is not about lenght) for any step-down stencil in order to get better results in my process.

Thanks in advance.

reply »

#22510

Squeegees for Step-Down stencil | 25 November, 2002

Now that is a BIG step.

Stencil type: * A metal squeegee is fine with stepped stencils. * A rubber squeegee is fine with stepped stencils.

Comments on step stencil "keepouts" are: * Use an ample space around the stepped down component pads that is stepped down to allow proper contact with the paste. * If you can accomplish it, placing the step on the board side of the stencil is better when using metal squeegees. * In your case, keep the step 120 [some would argue 160] thou from the pads of the component that is stepped .

Going back to the BIG step comment. Consider reducing the overall thickness of your stencil, while maintaining the 6 thou step.

reply »

#22534

Squeegees for Step-Down stencil | 27 November, 2002

In my haste to respond, I neglected to ask THE QUESTION.

What is it about your current process that you would like to improve?

While we're at it, tell us more about your: * Stencil * Paste * Printing process and set-up

reply »

Daan

#22612

Squeegees for Step-Down stencil | 6 December, 2002

I wouldn't recommend a metal squeegee, because if you can't wipe the step-etched area completely clean (that's the problem with metal) you'll have problems with the definition of the fine-pitch (it may stick in the holes). Best is a 70 Shore polyurethane squeeguee, or 90 if you have too much scooping out of the bigger apertures.

Daan Terstegge http://www.smtinfo.net

reply »

MA/NY DDave

#22624

Squeegees for Step-Down stencil | 9 December, 2002

Hi

I can image too many images for what your product or your process looks like.

Think about hiring a consultant to come in and really look at things.

YiE, MA/NY DDave

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

#22627

Squeegees for Step-Down stencil | 9 December, 2002

You want to use a rubber squeegee with as high as a durometer as you can get away with, order two or three sets of blades starting with the softest and then progress up the the hardest, the reasoning behind this is the softer squeegees will wear out quicker while scooping paste out of the aperatures all the while. Always have your squeegees .5 inches wider per side than the outermost aperatures you are printing.

reply »

Mark

#22892

Squeegees for Step-Down stencil | 2 January, 2003

Hello. Sometimes metal squeegees DO work with stepped stencils. You will always get much better results with metal squeegees compared to polymer blades.

The only requirement for the metal squeegee to work, you need about 0.06 in clearance for every 2-mils of step-down. In your case, you need about 0.13" clearence between the edge of the step and the aperature inside the step.

This spec is required on the edges of the step which are paralell to the print stroke.

Good Luck, Mark

reply »

PCB Soldering Tools

Used PCBA Equipment