Post by thread:EE Re: Solder Paste Printing, was Re: [EE] Fab@Hom

On 1/15/07, Sebastien Bailard <spam_OUTpenguinTakeThisOuTsupermeta.com> wrote: {Quote hidden}> On Monday 15 January 2007 23:11, Forrest W Christian wrote: > > Sebastien Bailard wrote: > > > I lurk on this list. Are you interested in building one? > > > > Actually, I'm wondering..... > > > > Could I use this to syringe print solder paste on a SMD board? > > > > I'm in the process of converting to SMD and really would like to avoid > > the stencil acquisition and use issues. Sticking a syringe on a "mill" > > with a mechanical plunger provides some intriguing ideas about how I > > could avoid the whole stencil thing altogether.. > > > > -forrest > > In theory this should work. Eventually we'd like to make all our boards that > way, putting down a layer of conductive material onto and into some > nonconductive block. (Literally printing circuit boards.) We haven't gone > very far with this: > reprap.blogspot.com/2005/05/first-successful-silver-paint-circuit.html > It's one of those "after the 1.0 release" features. This is not a real circuit, but could be a good joke. :) Vasile

On Wednesday 17 January 2007 00:27, Vasile Surducan wrote: {Quote hidden}> On 1/15/07, Sebastien Bailard <.....penguinKILLspam@spam@supermeta.com> wrote: > > On Monday 15 January 2007 23:11, Forrest W Christian wrote: > > > Sebastien Bailard wrote: > > > > I lurk on this list. Are you interested in building one? > > > > > > Actually, I'm wondering..... > > > > > > Could I use this to syringe print solder paste on a SMD board? > > > > > > I'm in the process of converting to SMD and really would like to avoid > > > the stencil acquisition and use issues. Sticking a syringe on a > > > "mill" with a mechanical plunger provides some intriguing ideas about > > > how I could avoid the whole stencil thing altogether.. > > > > > > -forrest > > > > In theory this should work. Eventually we'd like to make all our boards > > that way, putting down a layer of conductive material onto and into some > > nonconductive block. (Literally printing circuit boards.) We haven't > > gone very far with this: > > reprap.blogspot.com/2005/05/first-successful-silver-paint-circuit. > >html It's one of those "after the 1.0 release" features. > > This is not a real circuit, but could be a good joke. > > :) > > Vasile It's "Hello World". We were discussing rapid prototyping in the taigtools mailing list, and "griffin1913" had an interesting approach: to use compressed air and pulse-width modulation: --- Subject:[taigtools] Re: Check this out RAPID PROTOTYPING on a budget From: "griffin1913" <griffin1913@--redacted-to-keep-away-from-spambots-> To: taigtoolsKILLspamyahoogroups.com Date: Yesterday 08:35:51 pm I have designed automation equipment that does this in the past. You would be surprised how easy it is to keep extreme consistency with very low-tech systems. No metered syringes necessary. We used solenoid actuated nozzles, and simply controlled the opening times. The viscous liquid was kept at a constant pressure (in our case from from a regulated air source). There was no need to pre-measure it. Just put however much you will use in a sealed vessel and let the air or other constant force displace it. This allowed a lot of material to be available to the machine without constantly stopping to refill a metering device like a syringe. Fixed viscosity + fixed orifice size + fixed pressure = fixed flow rate. The only variable is the triggering time for opening the nozzle. Amazing accuracy is possible. This is actually the same principle your cars fuel injection system uses. Other variations of this are possible. As long as only ONE of the variables changes, you can get very accurate displacements, without needing to go as far as physically metering the mechanical displacement itself. (-griffin1913) ---

On Jan 16, 2007, at 9:27 PM, Vasile Surducan wrote: >> We haven't gone very far with this: >> <http://reprap.blogspot.com/2005/05/first-successful-silver-paint- >> circuit.html> >> It's one of those "after the 1.0 release" features. > > This is not a real circuit, but could be a good joke. > http://www.instructables.com/id/EBLX9QZU86EWH0ULQX/ But I think the original poster had in mind laying down solder paste on a REAL PCB; a sort of CNC solder-paste dispenser. It might work OK for that; I'd be concerned that it would be unable to put down sufficiently small amounts of paste; with a stencil, you're talking about putting down a very thin layer of paste. (but it ought to be as good as using a syringe by hand.) BillW