Hi Bill! Here's a old post from one of the dispensing "Gurus", Paul Klasek. They don't own a single stencil and have been doing all their SMT with dispensing solder paste...wish Paul was back up on the list... -Steve Gregory- Zoran Raich[SMTP:[log in to unmask]]> Sent: Wednesday, 3 February 1999 9:04> To: [log in to unmask]> Subject: Re: [TN] SMT dispensing systems Hi Wade, We are using a Camalot Gemini dispensing system. I being the most sceptical out of Paul Klasek and myself am now very much sold on dispensing systems for Sodder Paste as you guys call it. It has totally blown away my theories a had about screen printing. To give you some of the Benefits, The good Points 1: Solder Paste Wastage calculated at 4% (Call me inefficient but we had approx 30% with screen printing in past lives).Can be less still with better syringe (individual light (4 pumps) monitoring 2: Safety, operators prefer handling the tubes and is very clean with no mess.We went with 55cc EFD barrels , 2 mounted on back plane (on 644 pump 2inback , 2 in front ) ,200gr each ; 2 of them on back plane last a shift . Paradise . 3: Deposition Control. Ever had the problem where you wanted to control the amount paste using stencils but could not or were limited due to fine pitch constraints and aspect ratios (Stepped stencils can be a nightmare). It is interesting to note that coplaniarity issues with finer pitch devices and other IC's are negated dut to the dot height which eliminates dry joints due to coplaniarity issues.This was one of major considerations (fill in hole) for example pth anchoring of SMD connectors ;(those which should be on Steve's toshiba's mother of all boards ) ;the flexibility of tuning (hunting down the illusive balls) is tremendous ;you can dispense even on solder mask to let it creep up the fillet . 4: Flexibility with regards to frequent design changes, no need to buy multiple stencils through alpha, beta and production stages. 5: No cleaning of stencils or blocked apertures. 6: Paste rheology does not play a large role in dispensing negating the need to constantly work the paste during screen printing to achieve a consistant deposit (Mainly concerned with fine pitch) 7: Change over time between one product and another is as quick as loading another program and changing the Conveyor width (Again no need for stencil maintenance). The Not so Good Points 1: The solder paste is more expensive for -400 to +500 Mesh (Negated somewhat buy the wastage and waste handling but unfortunately the accountants do not see this, I suspect it has something to do with the personality bypass operation they have after certification) I think he says in the end it's the same on paste cost . 2: Programming can take a couple of hours to do depending on how many components there are but compared to stencils if you take into account the time taken to do aperture reductions and adjustements creating gerbers emailing them to stencil suppliers liasing with stencil suppliers creating purchase orders la di da etc etc programming time is not as bad as you first imagine. (Gosh ; he's really picky ; how often do you run new board in ?And 2 hours beats 2 days on stencil if yo're that fast , (+ COST ; and pray you dead right on those apertures ) . 3: You do sometimes get a missing dot here and there but nothing of major concern a little process control fixes this.We started with 325-500 mesh stock ; which we still unfortunately have touse up ;the 400-500 ind NC-SMQ90 is faultless (running a week on three shiftswithout cartridge and needle clean)We did validate it already ; did not implement in production yet . 4: It is slower than screen printing, you can not put them in front of fast chip shooters and utilise SMT machines effectively. We are on our boards getting approximately 70% of tact. So please note it depends on your production requirements, we are currently looking at buying the fastest dispenser on the market to take up this issue.This one is again in the take-off stage :We have here My19 with hydra and getting one more as it's from our opinionideal (almost 300 feeders) for a real bad mix as we have ;and once we deploy dual needles ( on 0805's or 603's ; 1206's ; you name it keep them in parallel orientation on design) ; the Gemini will comfortably keep up with My . Presently because this place is for god (chairman) knows what reason going through the stratosphere;we have little time to tingle the toys ; we can't get on them because production sits on it 24 hours 7days almost .That should change this year as Zoran goes to NW (kick tyres as he says) of XYFlex for this application .With him around I have more time for battles with R&D's dreams (they call it manufacturable designs) . These are some of the more obvious things which may be food for thought and help in the decision making process. Regards Zoran Raich ResMed Ltd www.resmed.com.au To sum it up Wade ; yo're on perfectly right line ; local subs think the same way ; on small runs the stencil pains are unbearable ;and with US market ; as Steve said ; I'm surprised you don't have dispensing lines by dozen's . Resent this mail to Indium guys ; (William Jackson . MD ;[log in to unmask] ; <A HREF="http://www.indium.com/">http://www.indium.com</A> ; ) ;if you don't get reply from Bill this week ;ask for resmed's 55cc 400-500 mesh ' ( I can not fault that paste, and did I try !) ; get from camelot (speedline mayhem now) the 644 head (last quoteI've heard was US $ 16K) ;with 4 extra cartridges ( $ 6+K more ) to rotate in maintenance cycle and yo're in business As you have likely already 642 head you can start with that ( no room for dual needles ) ;on mostly single 21 gauge we do , ( buy few of them operators will shear few of them on learning curve ) .Once you gain experience and establish dot sizing and spreads and component library the programming of new board should be less than 2 hours .To get there will take you about a month of clean time .If you have $ 5K spare I can send you a fellow with more than decade experience on Gem's ; or come myself ; or send another wise guy who started it all up with me .That is for ticket; food and place in the garage for sleepin' bag .See you Wade Paul Klasek <A HREF="http://www.resmed.com/">http://www.resmed.com</A> PS good to see subs waking up ; I'll try to dig up for you old camelot's charts of savings, line by line dispensing X printing .It's an eye opener I validated and verified last year as factual ( no wool ;no bull ) PPS Bill , any chance to "lend" Wade few of those 55cc barrels (400-500) for all of this good will ? Please .They go usually to Advaced Material Technologies - Aust .Thanks A lot PPPS If you've read the article from Chuck Bauer (smta) in Advanced Packaging (I think Steve's got a copy) ; I'd have to clarify it as Chuck painted it with bit to loose brush strokes ;some less correct than others ; let me know if you need any details (lets digitize) . NB almost forgot ; auger is the only way .As far as I see it ; there's only one on top = you got it ; II with stated 45K speed it is .When I calculated the balance you need on average mix 4x dispensing speed than p&p .That is apples with apples = stated x stated ; or actual x actual .the dual needle will get you to 60K with 644 ; design plays a role . From: Wade Oberle[SMTP:[log in to unmask]] Sent: Wednesday, February 03, 1999 3:13 AM To: [log in to unmask] Subject: [TN] SMT dispensing systems> Dear Technetters, I'm interested in who are the 'major players' in the SMT dispensing business. In my opinion, Camalot and Asymtek are on the top tier. I'd be interested to here other opinions and experience. Regards, Wade Oberle 414-947-3477 [log in to unmask]