PROBLEMS WHILE GLUE PRINTING

Using an enclosed pressurized printhead system will significantly reduce the waste produced compared to printing glue using squeegees. In trying to stay with the 0201 theme here, I will add that printing glue or adhesive for 0201s continues to be a challenge and a robust process still has yet to be defined. I recognize that you are looking for general recommended process guidelines. I can refer you to applications engineers who specialize with the glue/adhesive printing process to address this. Please click on my name to send me an e-mail if you are interested in pursuing this further.

-Jeff

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We use glue for all kinds of purposes. [See, first we glue the lock on the office door. Then, we glue dadour locks on dakah. Next, we glue the ignition of the Benz. Now, webee gon stylin�, uh huh!] Oooops, sorry got lost there for a minute, the dark side caught-up with me.

Assuming you�re talking about using glue to maintain component positioning during wave solder and solder reflow processes.

MESSY: Messy??? Messy. Well, the stuff IS epoxy. And epoxy is, um er, epoxy. [I think finger nail polish is messy, but my wife has never dripped a drib of the stuff in the ninety scadzillion times she�s done her nails over the 345 trepdillion years webin married. Now, THAT�S process control.]

GLUE SUPPLIERS: Loctite, Heraeus, Ciba Giegy, Emerson & Cuming Amicon, etc

CLEANING SQUEEGEES AND STENCILS BY HAND: We use our supplier�s recommended adhesive cleaner [solvent]. We also purchased a hand held ultrasonic stencil cleaner that works very well. Yasee, it's very important to keep the glue from curing in the apertures. Most certainly, cured glue will inhibit application of the proper amount of adhesive the next time you run that job. The stencil cleaner was a little expensive [$8k], but it has paid for itself in better placements and less rework.

STENCIL CLEANING MACHINES: The fine SMTnet Archives are rift with suppliers of expensive stencil cleaning machines. [At this precise moment, the trumpets are heralding the untold numbers of stencil cleaner sales-types to exclaim the virtues of their machines. Yano, they are virtually the only people that sell on SMTnet. I don�t get it!!!! They must have too much margin.]

See, these machines are made for BIG assembly shops and are priced to keep small shops out of the business. Smart, eh?

CLEANING CURED GLUE: Hammer and screwdriver from McMaster-Carr, Sears, Wal-Mart, etc

PROCESS: Most glue suppliers don�t get real excited about process development for printer, because the company that wants to print is chump change. Now dispensing, they�d like to talk dispensing. The people that want to talk printing adhesives are the printer people, because it extends their product line, keeps the dispensers from penetrating, etc. Check back issues of "SMT", "Circuits Assmebly", and "EP&P" magazines.

OK. So, let�s run with your supplier that �told us not to go for this process as it is too 'messy'�, what was this person�s suggestion? �Suppliers� that do not provide solutions are not suppliers.

Finally, there is a particularly insightful comparison of dispensing and printing in the fine SMTnet Archives, although it does come from a paste, as compared to the glue perspective, here.

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