Kevin,
We are also looking at printing adhesive. Our application involves printing glue on the underside of the board, once it has gone through the dip, axial & radial process. In otherwords, there are leads cut and clinched and we have to mill out channels so that these leads can sit into.
HOW?
Well, we are using a stencil, made out of a material called asotal. For our application the stencil is 1.5mm thick. The areas where there are leads clinched are milled out. The stencil can be upto 4 OR 5 mm for certain applications.
Were putting down bread and butter items. 0805's, 1206's, SOIC's, Melf diodes etc. The difference in speed is incredible. Like the other reply's to your question, if speed is needed, printing is quicker than any dispenser out there. We are seeing a complete cycle time of 30 seconds a panel compared to minutes in our dispenser.
Cleaning was a concern. It's a nightmare to clean by hand. You have to get every bit of glue out. \We have just invested in a cleaning machine and are using Vigon SC200. We intend using it for both cleaning paste and glue in the same solution. A couple of companys are using it for this appliaction already, and extensive trials have been done to say there are no concerns.
As for environmetal and glue exposure, I have managed to get some technical papers from Heraus who are our adhesive suppliers, which detail there humidity tests, exposure in terms of days and weeks, shear rates and rehology caluculations. All the good technical stuff that somebody somewhere understands.........I'm not claiming to!
We have trialled the stencil and it looks good. We are about to start production with it. The results look very promising and we will certainly be persuing this as a concept. If you need more info OR copies of information that I have found, please contact me.
Regards,
Joe.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ | OK, my manager read an article on printing glue (aaargghh!)and wants to know why we aren't doing it. We currently use Fuji GLs and GDMs to dispense glue. I've never done it, but have seen it done at NEPCON and other shows. It looks OK, BUT what are the pitfalls? Is it as easy as printing paste? Any info would be greatly appreciated (about the process, not how to keep technical magazines from my bosses hands). |
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