I am new to SMT Production Lines and was hoping to benefit from expert advice.
I currently have but still need to install:
manual essemtec stencil printer
old juki laser pick n place x2
IR T962c reflow oven
Dreaming about a fully automatic setup where pcb goes in and completed pcba comes out. The old jukis are running cheap because they dont have conveyors and are slow 4000cph. The conveyor model runs $10k and is only twice the speed but 10x the price.
Do I need to worry about manually handling a pcb array with 3000 smt parts when placing in desktop reflow oven? Do the parts shift easily? I have 75 QFN and 1250 0402 parts on 1 board which should take 1 hour to do. I plan to run 25 boards a day.
No problem. As long as you don't drop the board on the floor, it is VERY unlikely any part will shift. Umm, wait! ONE hour per board, and you want to do 25 per day? Will that really work? (Ahh, below, you say more machines.)
3000 total parts? So, about 45 minutes/board. However, if the machine has multiple nozzles, it may be able to pick and place several components at a time. My Philips can do that. It doesn't double the speed of the machine, but does speed it up a bit. Remember, you have to hand feed all this stuff, keep up with tapes running out and feeders jamming. Maybe it is because my machine is quite "old school" but there is a LOT of fooling around required to keep it running. Feeders jam, parts jump out of the pockets, nozzles get gummed up with paste, the machine can't find the fiducials because there's paste on them, and on and on. Running one machine it is not such a big deal, but if I had several machines in parallel, I'd never have them all running simultanously!
My Philips machine does have a conveyor, and I like it, but without a totally automated line it may not save a whole lot of time over hand feeding.
If its not an issue, I would prefer to buy 10 small jukis. Any insight appreciated.
TEN Juki machines? How many people will you hire to run all this? Compute the stencil print time and the oven time with the P&P time and figure out the optimum throughput. I doubt with one stencil printer and one oven you could keep 10 P&P busy. Unless I'm misunderstanding your 1 hour build time, I don't think you need more than, MAYBE, 2 or 3 P&P machines. This desktop oven is a BATCH oven? Then, it will be even slower. Probably runs close to 10 minutes/ board. Unless you are REAL careful, you will have MUCH bigger problems touching the board until it has cooled than worrying about the board BEFORE reflow.
Unless I am misunderstanding what you are wanting to do, it sounds like a recipe for madness. There are machines more suited for this level of production, such as some of the Assembeon GEM machines. They have 8 to 20 nozzles, and go over to the feeder rail and pick up a full "rack" of parts, then go to the board and drop all of them in a couple seconds. What I'm saying is that ONE machine that can plant a bunch of passives quickly may be a MUCH better way to go than a whole room full of slow machines that you have to babysit all day long.
Jon