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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Clint Meech

#16302

Plastic Stencils for screen printing ahesive | 8 April, 1998

We currently screen print glue for our bottom side components. We are looking to get the bottom side of one our boards screened with a solder resist (to cover mounting holes, etc, for the wave-soldering process). This would create an uneven surface for us to screen our glue on. I understand that plastic stencils are available, which could compensate for any solder resist material already deposited on the board. Who supplies such stencils, and has anybody had any experience (good or bad) with them? Thanks, Clint Meech

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Alan Pestell

#16304

Re: Plastic Stencils for screen printing ahesive | 8 April, 1998

We currently use the Loctite system of Glue/stencils and are getting very good results. You may still have a height problem is you solder resist is too thick. The UK sales person is Bob.goss@loctite-europe.com & he may give you more help. The only other point about plastic screens and glue is that you have to clean them in the suppliers cleaner (cost), or the screen retaining tape unsticks and your stencil & fraame part company ! And you must use plastic squeeges. Previously we did use a pealable solder resist from the pcb manfacturer to help us with wave soldering & masking, but the resist became soft and stuck to our belt in Reflow!! so watch out for this. Alan | We currently screen print glue for our bottom side components. | We are looking to get the bottom side of one our boards screened with a solder resist (to cover mounting holes, etc, for the wave-soldering process). | This would create an uneven surface for us to screen our glue on. | I understand that plastic stencils are available, which could compensate for any solder resist material already deposited on the board. | Who supplies such stencils, and has anybody had any experience (good or bad) with them? | Thanks, | Clint Meech

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mpark

#16303

Re: Plastic Stencils for screen printing ahesive | 8 April, 1998

Clint, You may want to call KJ Marketing Services, a Canadian company that fabricates plastic laser cut stencil. They call it "Kepoch stencil" This material was originally developed by Dupont, and patented and marketed by KJ. It was available for last 2 years. I performed some sample testings of the material. It feels, smells and looks like any other semi-transparent plastic material. It is extremely heat and wear resistent however if you scratch it with a pointed mechancial object, it will leave a good scratch mark. The price of stencil is same as getting a stainless laser cut stencil. You will find Kepoch stencil works better printing glue than using stainless stencil with rubber squeegee. I personally don't use it mainly due to that it is not compatible with metal squeegee and it offers no significant price reduction. However price is heck a lot better than Loctite plastic stencil. regards Matthew Park NII-Norsat International Inc. Contact: KJ Marketing Serivces Jerry Blatchford 115-30th St. Toronto, ON. Canada M8W 3C1 tel: 416-252-1061 fax: 416-253-1687 | We currently screen print glue for our bottom side components. | We are looking to get the bottom side of one our boards screened with a solder resist (to cover mounting holes, etc, for the wave-soldering process). | This would create an uneven surface for us to screen our glue on. | I understand that plastic stencils are available, which could compensate for any solder resist material already deposited on the board. | Who supplies such stencils, and has anybody had any experience (good or bad) with them? | Thanks, | Clint Meech

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