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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Using an air hose to clean stencils

Views: 4538

#63063

Using an air hose to clean stencils | 4 November, 2010

I need a second opinion.

My operators us an air hose to clean out the aperatures in our stencils. It is my contention that this puts solder into the air, and could be harmful to us. It is the operators contention that I am crazy, and cite as proof that none of us are dead yet.

Who is right?

reply »

#63064

Using an air hose to clean stencils | 4 November, 2010

You got my vote. I would not want to be on the other side of that stencil. Maybe your operators are just trying to save the company some money by collecting the excess solder paste and resuing it for future builds? I hope there are no bean counters reading this forum. Don't want them to get any ideas.

reply »

#63065

Using an air hose to clean stencils | 4 November, 2010

It would depend on the solder paste but the stuff we use is heavy enough that it wont go airborne. and theres really no other way to clean the apertures on a 0402 or similar part.

reply »

#63072

Using an air hose to clean stencils | 5 November, 2010

The smallest particle sixe for type 3 paste in 25 microns. This is far to big to remain airborne.Therefore I would suggest to continue to use air to clean stencils as it does clean the apertures effectively.What solvent is used to clean the stencils?

reply »

#63074

Using an air hose to clean stencils | 5 November, 2010

I agree with the others - I just don't see the danger. We've been using air to help clean stencils for decades.

reply »

#63075

Using an air hose to clean stencils | 5 November, 2010

What about trying to clean these stencils with a proper stencil cleaner? This way you wouldn't have to worry about sending anything airborne.

reply »

#63082

Using an air hose to clean stencils | 5 November, 2010

I think you are right. According to IPC-7526 section 6.2 says that using compressed air to blow out paste will damage the stencil, especially between fine pitch apertures. It can also broadcast solder paste onto other surfaces or personnel.

I recommend you download the free IPC-7526 Stencil and Misprinted Board Cleaning Handbook at http://www.ipc.org. It covers a wealth of information about cleaning stencils and boards. The proper way is by using a stencil cleaning machine.

reply »

#63084

Using an air hose to clean stencils | 5 November, 2010

I agree that the tines (webs between apertures) can become damaged on fine pitch stencils from a blast of air. If they get bent, the stencil won't seat and gasket properly allowing bleed out of paste. Of course we all know that the air being blasted from that air gun will be oil and water free by passing thru filters right?

reply »

#63121

Using an air hose to clean stencils | 12 November, 2010

I would also be concerned about spreading solder paste on the walls/floor/equipment downstream of the air. This would then get transfered to hands, clothing and shoes. In turn, tracked out to the rest of the floor/building or even to the home of employees.

reply »

PCB Soldering Tools

Used SMT Equipment