recommendation for small volume SMT assembly - Page 1
Forum section: electronics / general

author: EngF
author_rank: Newbie
timestamp: October 28, 2019, 04:13:26 pm
content: Good Morning/Afternoon Gentz,I am planing to start-up an small volume smt assembly for own developed products. I have been searching a lot for suitable machines and you know how many copycat and bad quality machines available. while searching a come cross this forum and red couple of threads and I hope you can help find a reliable machines supplier. here are what I'm looking forStencil machine/ automatic solder dispenser (not sure if dispenser is reliable technique)PnP Machine (red about Yvi110 but not sure if there are any problem with custom)re-flow ovenconformal coating machine (to be specific also with chemical should be good with high relative humidity some time reaches 83% and temp 50+ under sun and 49- in shadow)I know china services is cheap for low/mid volume but lead time is highly important for me. looking forward for your replaysFahad

author: SMTech
author_rank: Frequent Contributor
timestamp: October 28, 2019, 10:42:22 pm
content: Realistically dispensing is not an option unless you want to spend a LOT of money.PnP - you need to define your interpretation of low volume both in terms of how many boards and how may components are on those boards. You also need to work out what is important to you on the machine - easy to use software, size, price, feeders, capability, face to face support because these things affect what you should even be considering.Printing- you still need some of the answers from above, basic manual printers are what they are, there's a few differences in the shrinking semi-automatic range and lots of old or new fully automatic.Reflow - yeah still questions, although most low volumes should be quite well suited with Vapor Phase which can be both compact and effective.Conformal coating - well there a couple of brands out there that are pretty big in that department but before you get into automated machines, plenty of things can be done using a spray gun and suitable masking but this is a complex subject with all sorts of options and requirements like cleaning, ventilation, curing etc. Read some white papers, check out what other people who offer the service tell you on their websites etc etc.

author: Mangozac
author_rank: Frequent Contributor
timestamp: October 28, 2019, 11:00:09 pm
content: Indeed, "small volume" means very different things to different people! More specifically you need to indicate number of boards per year, number of components per board and number of unique components per board. Rough ballparks are good enough.

author: Psi
author_rank: Super Contributor
timestamp: October 28, 2019, 11:19:19 pm
content: I did very small volume SMT assembly myself at home over a period of 3 years or so.I needed around 10-20 units a week which took about 1 day or so to complete.Depending how much youtube/music i had running while i worked- I applied solder paste using a stencil and squeegee.It does take some practice to get good, but once you know how it's pretty easy to get a nice sharp solder paste image applied.This step is very quick once you're setup with a place to sit the pcbs and the stencil hinged down from one side.It would take like 2min to do 10 boards.One thing i learns was to use good quality solder paste. I always had random results with chipquik but when i switched to a more expensive brand that went away. (before someone asked, yes, i kept it in the fridge). Getting the paste to the right consistency where you get sharp images is probably the most tricky part of the process. Alignment is tricky but totally find once you get the hang of it.- Placing parts.I setup a vacuum pickup tool by plumbing a syringe into the solder fume extractor port on my Aoyue 968 soldering station.I added a T valve into the line where i could adjust the suction on it by closing/opening one of the ports.I had no real time control over the suction while picking and placing. I just set it so it could pickup small parts 0805/small chips etc.. and left it set to that. It worked great. The solder paste was sticky enough to overcome the vacuum and hold the part to the PCB.I had a lazy susan (rotating table) setup where i had PCBs placed around the edges and bigger/unique parts placed behind them.This meant i could work under the microscope on each PCB, placing its parts and then just rotate the lazy susan to the next PCB and its parts.For passives i used the vacuum tool to pull parts out of cut tape. Doing all of one value on all boards then grabbing a new value and rotating the table around again etc..-Reflow i did in a toaster oven.This worked fine, never had any problem with it.Used DMM temp probe and set variac to correct voltage to get 215 degCTimed 4min and they were done.

author: Alicelllly2020
author_rank: Contributor
timestamp: October 29, 2019, 01:54:55 am
content: Hi Fahad，Greetings, this is Alice from Neoden.What is your smallest component size and max PCB size?For small volume SMT assembly, Neoden3V or Neoden4 SMT lines might be suitable:Stencil machine/manual high precision solder printer FP2636PnP Machine/Neoden3V or Neoden4re-flow oven/ IN6Attached 2 photos for your reference. No hesitate to contact if you have any requirement.Best regards,AliceEmail: sales4@neodentech.comWhatsapp:+86 13588176839Skype: Alice-Neoden

author: EngF
author_rank: Newbie
timestamp: October 29, 2019, 02:01:44 pm
content: Quote from: SMTech on October 28, 2019, 10:42:22 pmFirst and for most thank for replayin term of PnP:Number of boards 5 - 10 packages per month (1 package = 15-17 boards) note:there is expected increaseNo. of components: not finalized yet but one thing in mind is bulky components (Relays)proper support and warranty servicesQuality and less failure ratePrinting I am already consider the manual and just needed to confirm what you said about dispenserReflow Vapor phase more please (Just search for it and basically provide more uniformity than IR reflow).

author: EngF
author_rank: Newbie
timestamp: October 30, 2019, 03:11:37 pm
content: Quote from: Psi on October 28, 2019, 11:19:19 pmi salute youcouple of questionhow long did it take you to do it righthow many failed attempted board did you get?all your doing is amazing but thing what if there is increase in volume ?

author: jmelson
author_rank: Super Contributor
timestamp: October 30, 2019, 07:16:07 pm
content: Quote from: EngF on October 30, 2019, 03:11:37 pmI bought a used Philips P&P machine in 2007. I had it up and running in a week, having never seen a P&P machine in person before. I did ask a lot of questions on SMTNET and got useful info from a number of people. The more complex issue was learning how to make my own solder stencils using essentially PCB manufacturing equipment. Dry film resist, FeCl etching.QuoteWell, very few, actually. The first board was smoked before I figured out to put the thermocouple into a plated-through hole in the board, so as to measure actual board temperature, not the air in the oven.Then, it took a while to learn the secrets of solder aperture sizing. For 0805 parts, you can use a stencil aperture equal to the pad size. For anything smaller, you want to reduce the aperture to be smaller than the pad. As the pads and spacing get smaller (like TSSOP) you have to reduce apertures to about 60% of the pad area, or more. And, I use .003" (.075mm) stencils.If you put too much solder paste on the board, you get bridges, and even more causes the chips to float away on lakes of solder. This was the hardest thing do get up to speed on. But, I was making usable boards, they just needed a little rework after reflow to fix the solder bridges.Good solder is extremely important. I have only found two that are very good. I was referred to Warton Metals, and imported a jar from the UK to the US at great expense. Now, I can get Henkel GC10 in the US under the Loctite brand. This works so much better than a number of other brands (Chip_Quik, AIM, Kester, Indium, etc.) I pretty much only do lead-free, so that is a bit more demanding than leaded solders.I have done over 2000 boards with hand-applied stencil, P&P and toaster oven reflow.QuoteWell, if volume increases, you can buy a conveyorized reflow oven and whatever level of stencil printer fits your needs, and maybe upgrade the P&P too.Jon

author: EngF
author_rank: Newbie
timestamp: October 30, 2019, 08:28:41 pm
content: Quote from: jmelson on October 30, 2019, 07:16:07 pmvery informative. I see alot of people mentioning old PnP Yamaha Philips and GSM which something good business wise but with old comes alot of risk. For example in the Industry that I currently work in we will look for (probability of failure on demand, Mean time between failure, and spare part availability) of the equipment. second to me is inspection as most used PnP is overseas which is a challenge.Fahad

author: jmelson
author_rank: Super Contributor
timestamp: October 31, 2019, 08:22:41 pm
content: Quote from: EngF on October 30, 2019, 08:28:41 pmWell, we only run our P&P machine a few times a month, doing relatively small runs of boards. Anywhere from 12 to 60 boards one run. Our machine has been pretty reliable. We had a conveyor optical sensor go bad early on, and it caused it to drop a few completed boards on the floor. That was hard to diagnose until it went to a near-solid failure. Then it was easy to be sure the sensor, itself was the bad unit. I've had a few sticky air cylinders, the vacuum/suction valves on the nozzles need to be cleaned yearly as they suck up the lube oil. Then I had the rotation motor's commutator getclogged with copper dust. That took some diagnosing and guesswork, as the machine's error message was VERY vague. And, I've had a few air hoses break, but these were VERY easy to diagnose.Anyway, none of these problems really shut down the production line for very long, just caused some worrying, until the problem was understood.Jon

author: GerardG
author_rank: Regular Contributor
timestamp: November 01, 2019, 03:45:15 pm
content: Hello Fahad,If you WANT to do some dispensing it is possible to use the Voltera V-One.No hassle to make or buy a stencil. You just downsize the pads of the gerber and start production.You can ask some information from voltera.ioI used both methods, for prototyping use dispensing and using metal stencils in an fp-2636.