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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Kevin Hussey

#11568

Printing Adhesive | 5 May, 1999

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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Mark Lessig

#11569

Re: Printing Adhesive | 5 May, 1999

Hello Kevin, I work for a leading manufacturer of paste and adhesives and have alot of experience with printing smt adhesives. We also have publications that can lead you to better understand the process. Printing of adhesives are as easy as printing solder paste. If your printing process is up to par adhesives will print very easily. We have done it using a hand squeegee methode but I would recommend using a screen printer. I will be happy to send you information of printing adhesives, if you will provide me with a mailing address. As you mentioned, " what are the pitfalls". I think the only pitfalls that exist are cleanup. Printable adhesives are somewhat hard to clean and should be cleaned using a chemical with the strength of acitone. There are many available and we could recommend some. If you would like to discuss this call me at 610 825 6050 x249 Thanks

| 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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Dean

#11570

Re: Printing Adhesive | 5 May, 1999

| 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). | There is only one advantage to printing epoxy. Process speeds can dip as low as 10 seconds when printing epoxy with a stencil. There are far more "cons" associated with printing adhesives than dispensing machines. 1. The chemicles used to clean stencils are generally considered hazardous material (acetone, xylol, Methyl ethyl detone MEK, ) This adds a safety concern to cleanup. 2. Material waste. Epoxy is hydroscopic. Unnecessary exposure to the atmosphere can cause problems in reflow (steam cavities causing brittle bonding and solder entrapment) This will require process exposure evaluation. Exposed material should never be "recycled". This increased waste adds cost to your process. 3. The foil thickness partially determines deposition volumes and can not be altered. This limits the range of components (stand-off height) which can be reliably epoxied with a stencil. (not an issue if chips only). 4. Release characteristics of epoxy differ from solder paste. Aperture dimensions and shape must be considered. The smaller the aperture the greater the difficulty in release (especially with aspect ratios greater than 3 to 1).

I have used both dispensing machines and stencil printing epoxy and perfer the flexibility associated with dispensing machines and ease of cleanup. In addition, the safety and prevention of exposure to solvents is paramount to the operator staff. However, if process times and product suitability are the driving factors I would (begrudgingly) return to printing epoxy.

Dean

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Sokkhon Ou

#11571

Re: Printing Adhesive | 6 May, 1999

| Hello Kevin, I work for a leading manufacturer of paste and adhesives and have alot of experience with printing smt adhesives. We also have publications that can lead you to better understand the process. | Printing of adhesives are as easy as printing solder paste. If your printing process is up to par adhesives will print very easily. We have done it using a hand squeegee methode but I would recommend using a screen printer. I will be happy to send you information of printing adhesives, if you will provide me with a mailing address. | As you mentioned, " what are the pitfalls". I think the only pitfalls that exist are cleanup. Printable adhesives are somewhat hard to clean and should be cleaned using a chemical with the strength of acitone. There are many available and we could recommend some. | If you would like to discuss this call me at 610 825 6050 x249 | Thanks | | | | | | 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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Joe Manzur

#11572

Re: Printing Adhesive | 6 May, 1999

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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JohnW

#11573

Re: Printing Adhesive | 6 May, 1999

| 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). |

Kevin,

We've been screen printing glue for a while, on comps from 0402's rightt up to SO20's and even managed a QFP! not to be done on a regular basis tho!. Anyway's we're using a varidot process where you've basically got a circular hole in the stencil the size of the dot determin's the hieght of the glue deposited. Normally it's an on contact method although you can do a snap off version. Print speed's are comparable with paste printing, some are even faster. Decent printing glue has got a pretty good stencil life but the killer is cleaning it. It cure's in air over a long time..typically 3hrs or there about's and after that it's a bitch to move. So the key is to rememebr to clean the screen after it. I'm running metal blades as well and getting real good quality. Gluing melf's aint fun but the trick is to use either 2 dot's or a bar of glue in the centre to stop it rolling around - did you know that there are direct 1206 & 0805 alternatives to melf's that just drop in ? worth looking them out makes life so much easier.

talk to your stencil manufacturer and the glue supplier for technical help, they generally are keen to get in there and lend a hand.

John

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John Staley

#11574

Re: Printing Adhesive | 7 May, 1999

| Kevin, I also work for a major adhesive manufacturer and would be pleased to send you several technical papers and some basic equipment settings for printing adhesives. If you will leave you name and mailing address on my voice mail (800)323-6106 ext 6165 I send the information on to you.

Hello Kevin, I work for a leading manufacturer of paste and adhesives and have alot of experience with printing smt adhesives. We also have publications that can lead you to better understand the process. | | Printing of adhesives are as easy as printing solder paste. If your printing process is up to par adhesives will print very easily. We have done it using a hand squeegee methode but I would recommend using a screen printer. I will be happy to send you information of printing adhesives, if you will provide me with a mailing address. | | As you mentioned, " what are the pitfalls". I think the only pitfalls that exist are cleanup. Printable adhesives are somewhat hard to clean and should be cleaned using a chemical with the strength of acitone. There are many available and we could recommend some. | | If you would like to discuss this call me at 610 825 6050 x249 | | Thanks | | | | | | | | | | | 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). | | | | | | | | |

reply »

#11575

Re: Printing Adhesive | 7 May, 1999

Just a note about cleaning SMD adhesives. Cleaning does not need to be hazardous. Smart Sonic has a non hazardous process that has been used for over 9 years using a non hazardous detergent that has been certified by the AQMD as a clean air chemistry and verified safe by the U.S. Environmental Protection Agency as part of their Environmental Technology Verification (ETV) Program. Call me or e-mail me and I will send you a copy of our Applications Update for cleaning SMD adhesives. Bill Schreiber Tel: (800) 806-440-R E-mail: bill@smartsonic.com

| | 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). | | | There is only one advantage to printing epoxy. Process speeds can dip as low as 10 seconds when printing epoxy with a stencil. There are far more "cons" associated with printing adhesives than dispensing machines. | 1. The chemicles used to clean stencils are generally considered hazardous material (acetone, xylol, Methyl ethyl detone MEK, ) This adds a safety concern to cleanup. | 2. Material waste. Epoxy is hydroscopic. Unnecessary exposure to the atmosphere can cause problems in reflow (steam cavities causing brittle bonding and solder entrapment) This will require process exposure evaluation. Exposed material should never be "recycled". This increased waste adds cost to your process. | 3. The foil thickness partially determines deposition volumes and can not be altered. This limits the range of components (stand-off height) which can be reliably epoxied with a stencil. (not an issue if chips only). | 4. Release characteristics of epoxy differ from solder paste. Aperture dimensions and shape must be considered. The smaller the aperture the greater the difficulty in release (especially with aspect ratios greater than 3 to 1). | | I have used both dispensing machines and stencil printing epoxy and perfer the flexibility associated with dispensing machines and ease of cleanup. In addition, the safety and prevention of exposure to solvents is paramount to the operator staff. | However, if process times and product suitability are the driving factors I would (begrudgingly) return to printing epoxy. | | Dean |

reply »

#11576

Re: Printing Adhesive | 7 May, 1999

Just a note about cleaning SMD adhesives. Cleaning does not need to be hazardous. Smart Sonic has a non hazardous process that has been used for over 9 years using a non hazardous detergent that has been certified by the AQMD as a clean air chemistry and verified safe by the U.S. Environmental Protection Agency as part of their Environmental Technology Verification (ETV) Program. Call me or e-mail me and I will send you a copy of our Applications Update for cleaning SMD adhesives. Bill Schreiber Tel: (800) 806-440-R E-mail: bill@smartsonic.com

| | 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). | | | There is only one advantage to printing epoxy. Process speeds can dip as low as 10 seconds when printing epoxy with a stencil. There are far more "cons" associated with printing adhesives than dispensing machines. | 1. The chemicles used to clean stencils are generally considered hazardous material (acetone, xylol, Methyl ethyl detone MEK, ) This adds a safety concern to cleanup. | 2. Material waste. Epoxy is hydroscopic. Unnecessary exposure to the atmosphere can cause problems in reflow (steam cavities causing brittle bonding and solder entrapment) This will require process exposure evaluation. Exposed material should never be "recycled". This increased waste adds cost to your process. | 3. The foil thickness partially determines deposition volumes and can not be altered. This limits the range of components (stand-off height) which can be reliably epoxied with a stencil. (not an issue if chips only). | 4. Release characteristics of epoxy differ from solder paste. Aperture dimensions and shape must be considered. The smaller the aperture the greater the difficulty in release (especially with aspect ratios greater than 3 to 1). | | I have used both dispensing machines and stencil printing epoxy and perfer the flexibility associated with dispensing machines and ease of cleanup. In addition, the safety and prevention of exposure to solvents is paramount to the operator staff. | However, if process times and product suitability are the driving factors I would (begrudgingly) return to printing epoxy. | | Dean |

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